The introduction to Model Context Protocol starts out with: MCP is an open protocol that standardizes how applications provide context to LLMs. Think of MCP like a USB-C port for AI applications. Just as USB-C provides a standardized way to connect
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By Thomas Ptacek
16 min Read
Tech execs are mandating LLM adoption. That’s bad strategy. But I get where they’re coming from. Some of the smartest people I know share a bone-deep belief that AI is a fad — the next iteration of NFT mania. I’ve been reluctant to push back on the
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By Sam Ruby
3 min Read
Agile Web Development with Rails 8 is off to production, where they do things like editing, indexing, pagination, and printing. In researching the chapter on Deployment and Production, I became very dissatisfied with the content available on Kamal. I
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By Peter Cai & Pavel Borzenkov
22 min Read
The basic idea is simple: customers give us Docker containers, and tell us which one of 30+ regions around the world they want them to run in. We convert the containers into lightweight virtual machines, and then link them to an Anycast network. If y
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By Ben Johnson
8 min Read
Nearly a decade ago, I got a bug up my ass. I wanted to build full-stack applications quickly. But the conventional n-tier database design required me to do sysadmin work for each app I shipped. Even the simplest applications depended on heavy-weight
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By Sam Ruby
4 min Read
The Model Context Protocol is days away from turning six months old. You read that right, six months old. MCP Servers have both taken the world by storm, and still trying to figure out what they want to be when they grow up. There is no doubt that M
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By Sam Ruby
6 min Read
On Monday, I created my first fly volume using an MCP. For those who don’t know what MCPs are, they are how you attach tools to LLMs like Claude or Cursor. I added support for fly volume create to fly mcp server, and it worked the first time. A few h
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By Kurt Mackey
4 min Read
well, Cursor built I built the most basic MCP server for flyctl I could think of. It took 30 minutes. MCP, for those unaware, is the emerging standard protocol for connecting an LLM (or an app that drives an LLM in the cloud, like Claude Desktop) to
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By Kurt Mackey
10 min Read
It’s weird to say this out loud! For years, one of our calling cards was “developer experience”. We made a decision, early on, to be a CLI-first company, and put a lot effort into making that CLI seamless. For a good chunk of our users, it really is
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By Thomas Ptacek
15 min Read
1 We’ve spent too much time talking about security tokens, and about Macaroon tokens in particular. Writing another Macaroon treatise was not on my calendar. But we’re in the process of handing off our internal Macaroon project to a new internal owner
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By Peter Cai
7 min Read
The basic idea of our service is that we run containers for our users, as hardware-isolated virtual machines (Fly Machines), on hardware we own around the world. What makes that interesting is that we also connect every Fly Machine to a global Anycas
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By Kurt Mackey
10 min Read
A couple years back, we put a bunch of chips down on the bet that people shipping apps to users on the Internet would want GPUs, so they could do AI/ML inference tasks. To make that happen, we created Fly GPU Machines. A Fly Machine is a Docker/OCI
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By Thomas Ptacek
13 min Read
Question 1: Why, JP? Just why? LOL. When I looked at what I wanted to see from here in the next 3-4 years, it didn’t really match up with where we’re currently heading. Specifically, with our new focus on MPG [Managed Postgres] and [llm] [llm]. Edit
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By Thomas Ptacek
4 min Read
This whole paragraph is just one long sentence. God I love just random-ass blogging again. This bit by Geoffrey Huntley is super interesting to me and, despite calling out that LLM-driven development agents like Cursor have something like a 40% succe
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By Thomas Ptacek
4 min Read
Over the last 5 years, we’ve done pretty well for ourselves writing content for Hacker News. And that’s mostly been good for us. We don’t do conventional marketing, we don’t have a sales team, the rest of social media is atomized over 5 different sit
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By Thomas Ptacek
3 min Read
We’re interested in getting integrated into the flow VSCode uses to do remote editing over SSH, because everybody is using VSCode now, and, in particular, they’re using forks of VSCode that generate code with LLMs. ”hallucination” is what we call it
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By Chris McCord & José Valim
8 min Read
Let’s begin by introducing our cast of characters. Livebook is usually described as Elixir’s answer to Jupyter Notebooks. And that’s a good way to think about it. But Livebook takes full advantage of the Elixir platform, which makes it sneakily powe
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By Thomas Ptacek
8 min Read
Public cloud billing is terrifying. The premise of a public cloud — what sets it apart from a hosting provider — is 8,760 hours/year of on-tap deployable compute, storage, and networking. Cloud resources are “elastic”: they’re acquired and released
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By Kurt Mackey
6 min Read
We just lowered the prices on NVIDIA L40s GPUs to $1.25 per hour. Why? Because our feet are cold and we burn processor cycles for heat. But also other reasons. Let’s back up. We offer 4 different NVIDIA GPU models; in increasing order of performanc
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By Thomas Ptacek
18 min Read
At the heart of our platform is a systems design tradeoff about durable storage for applications. When we added storage three years ago, to support stateful apps, we built it on attached NVMe drives. A benefit: a Fly App accessing a file on a Fly Vo
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By Moss Lilley
10 min Read
Let’s hypopulate you an app serving generative AI cat images based on the weather forecast, running on a g4dn.xlarge ECS task in AWS us-east-1. It’s going great; people didn’t realize how dependent their cat pic prefs are on barometric pressure, and
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By Nolan Darilek
14 min Read
Picture this, if you will. You’re blind. You’re in an unfamiliar hotel room on a trip to Chicago. If you live in Chicago IRL, imagine the hotel in Winnipeg, the Chicago of the North. You’ve absent-mindedly set your coffee down, and can’t remember w
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By Lillian Berry
10 min Read
One of many odd decisions we’ve made at Fly.io is how we use WireGuard. It’s not just that we use it in many places where other shops would use HTTPS and REST APIs. We’ve gone a step beyond that: every time you run flyctl, our lovable, sprawling CLI,
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By Senyo Simpson & JP Phillips
8 min Read
Fly Kubernetes is the “blessed path"™️ to using Kubernetes backed by Fly.io infrastructure. Or, in simpler terms, it is our managed Kubernetes service. We take care of the complexity of operating the Kubernetes control plane, leaving you with the unf
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By Xe Iaso
9 min Read
There are three hard things in computer science: Cache invalidation Naming things Doing a better job than Amazon of storing files Of all the annoying software problems that have no business being annoying, handling a file upload in a full-stack a
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By Xe Iaso
2 min Read
GPUs are now available to everyone! We know you’ve been excited about wanting to use GPUs on Fly.io and we’re happy to announce that they’re available for everyone. If you want, you can spin up GPU instances with any of the following cards: Ampere
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By Chris Fidao
6 min Read
Serverless is great because is has good ergonomics - when an event is received, a “not-server” boots quickly, code is run, and then everything is torn down. We’re billed only on usage. It turns out that Fly.io shares many of the same ergonomics as s
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By Annie Sexton
12 min Read
There are many ways to delegate work in web applications, from using background workers to serverless architecture. In this article, we explore a new machine pattern that takes advantage of Fly Machines and distinct process groups to make quick work
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By Thomas Ptacek
22 min Read
1 Let’s implement an API token together. It’s a design called “Macaroons”, but don’t get hung up on that yet. First some throat-clearing. Then: Wrap text Copy to clipboard import sys impor
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By Xe Iaso
12 min Read
Hello all, and welcome to another episode of How I Fly, a series where I interview developers about what they do with technology, what they find exciting, and the unexpected things they’ve learned along the way. This time I’m talking with Yoko Li, an
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By Kyle McLaren
15 min Read
Some people daydream about normal things, like coffee machines or raising that Series A round (those are normal things to dream about, right?). I daydream about commanding a fleet of chonky NVIDIA Lovelace L40Ss. Also, totally normal. Well, fortunate
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By Sam Ruby
6 min Read
Before proceeding, a caution. This is an engineering trade-off. Test carefully before deploying to production. By the end of this blog post you should have the information you need to make an informed decision. Introduction Alpine Linux is a Linux
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By Senyo Simpson
10 min Read
Update, March 2024: FKS does more stuff now, and you can read about it in Fly Kubernetes does more now We’ll own it: we’ve been snarky about Kubernetes. We are, at heart, old-school Unix nerds. We’re still scandalized by systemd. To make matters mor
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By Xe Iaso
7 min Read
AI is pretty fly AI is apparently a bit of a thing (maybe even an thing come to think about it). We’ve seen entire industries get transformed in the wake of ChatGPT existing (somehow it’s only been around for a year, I can’t believe it either). It’s l
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By Xe Iaso
14 min Read
GPU hardware will let our users run all sorts of fun Artificial Intelligence and Machine Learning (AI/ML) workloads near their users. But, what are these “GPUs” really? What can they do? What can’t they do? Listen here for my tale of woe as I spell
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By Xe Iaso
12 min Read
Open-source self-hosted AI tools have advanced a lot in the past 6 months. They allow you to create new methods of expression (with QR code generation and Stable Diffusion), easy access to summarization powers that would have made Google blush a deca
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By Chris McCord
19 min Read
Imagine if you could auto scale simply by wrapping any existing app code in a function and have that block of code run in a temporary copy of your app. The pursuit of elastic, auto-scaling applications has taken us to silly places. Serverless/FaaS
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By Mark Ericksen
15 min Read
The topic of “AI” gets a lot of attention and press. Coverage ranges from apocalyptic warnings to Utopian predictions. The truth, as always, is likely somewhere in the middle. As developers, we are the ones that either imagine ways that AI can be use
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By Sam Ruby
6 min Read
Scaling discussions often lead to recommendations to add more memory, more CPU, more machines, more regions, more, more, more. This post is different. It focuses instead on the idea of decomposing parts of your applications into event handlers, sta
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By Xe Iaso
2 min Read
Previously when you ran fly launch, you got asked a bunch of hopefully relevant questions to help you get your app up and running. We’ve taken a lot of the guesswork out of the process and made it a lot more streamlined. It turns out that even though
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By Xe Iaso
6 min Read
I’m Xe Iaso. I’m a writer, technical educator, and philosopher who focuses on making technology easy to understand and scale to your needs. I use Fly.io to host my website and in nearly all of my personal projects now. Fly.io allows me to experiment
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By Chris Fidao
9 min Read
Fly.io has GPU Machines, which means we can finally run AI workloads with just a few API calls. This is exciting!
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By Ben Johnson
6 min Read
My favorite part about building tools is discovering their unintended uses. It’s like starting to write a murder mystery book but you have no idea who the killer is! History is filled with examples of these accidental discoveries: WD-40 was original
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By Joshua Sierles
3 min Read
We’ve been using Sentry since the dawn of the internet. Or at least as far back as the discovery of the Higgs boson. Project to project, the familiar Sentry issue detail screen has been our faithful debugging companion. Today it’s no exception: All
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By Ben Johnson
8 min Read
When we started the LiteFS project a year ago, we started more with an ideal in mind rather than a specific implementation. We wanted to make it possible to not only run distributed SQLite but we also wanted to make it… gasp… easy! There were hurdle
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By Sam Ruby
5 min Read
You’ve done everything right. You are well aware of Murphy’s Law. You have multiple redundant machines. You’ve set up a regular back up schedule for your database, perhaps even are using LiteFS CLoud. You ship your logs to LogTail or perhaps some o
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By Ben Toews
10 min Read
We built some little security thingies. We’re open sourcing them, and hoping you like them as much as we do. In a nutshell: it’s a proxy that injects secrets into arbitrary 3rd-party API calls. We could describe it more completely here, but that woul
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By Sam Ruby
2 min Read
Bun 1.0 comes out September 7th. Fly.io is making preparations. Previously, we stated that Fly.io ❤️ JS, and we understandably started with Node.js. While that work is ongoing, it makes sense to start expanding to other runtimes. Bun is the obvio
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By Darla Magdalene Shockley & Ben Johnson
9 min Read
We love SQLite in production, and we’re all about running apps close to users. That’s why we created LiteFS: an open source distributed SQLite database that lives on the same filesystem as your application, and replicates data to all the nodes in you
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By Kurt Mackey
6 min Read
This past July, we raised $25MM from A16Z and our existing investors, including Intel Capital and Dell. Recently, we raised an additional $70MM led by EQT Ventures. Why do startups write announcements like these? We went back and forth on it. There a
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By Darla Magdalene Shockley
10 min Read
Last year, while working in what was my day job at the time (before I joined Fly.io!), we had just developed a new internal tool to help an adjacent team with their work. This adjacent team wrote technical content, and they had a lot of issues stemmi
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By Sam Ruby
11 min Read
Recapping where we are to date: There are plenty of JavaScript frameworks to choose from, and fly.io loves them all. Pretty much all of the big name frameworks are delightfully weird. Picking up where we left off, this blog post will describe lite
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By Chris Fidao
7 min Read
The Fly Replay header is deceptively simple. All your app has to do is respond with a header, and the HTTP request gets re-ran somewhere else. It’s behind-the-scenes of some pretty interesting apps on Fly.io (we wrote about using it with Globally Di
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By Sam Ruby
7 min Read
Note, I’m not saying that JavaScript is weird, though it definitely is weird. But that’s not the point of this blog post. Bear with me, instead of starting with how JavaScript ecosystem is weird, I’m going to start with why the JavaScript ecosystem
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By Kátia Nakamura
14 min Read
I hear about Large Language Models (LLM) everywhere these days! Do you? 🤔 LLMs are a type of natural language processing (NLP) technology that uses advanced deep learning techniques to generate human-like language. If you haven’t heard about LLMs, y
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By Sam Ruby
6 min Read
Fly.io is a great place to run fullstack applications. For most programming languages, there is a defacto default fullstack framework. For Ruby, there is Rails. For Elixir, there is Phoenix. For PHP there is Laravel. For Python, there is Django.
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By Ben Johnson
5 min Read
In the field of computer science, the industry is represented by two separate yet equally important groups: the software developers who build Rails applications and mobile games, and the academics who write theory papers about why the problems those
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By Chris Fidao
5 min Read
Nearly all of our apps are puking output. Sometimes, it’s intentional. Often this output is in the form of structured logs. Logs are helpful for a variety of use cases - debugging, tracking, collating, correlating, coalescing, and condensing the ha
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By Thomas Ptacek
26 min Read
So, you want to build an app to rate sandwiches. Well, the world has a lot of different sandwiches. Pit beefs in Baltimore, Tonkatsu sandos in Shinjuku, and Cemitas in Puebla. You want real-time sandwich telemetry, no matter the longitude of the sand
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By Chris Nicoll
<1 min Read
Did you know that we’re in Johannesburg? There’s rugby and cricket. Hearty kota and Gatsby sandwiches. Braii under sunny skies and low-latency full-stack apps. Front end, Postgres, Redis, the works: if your users support the Springboks and Banyana Ba
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By Ben Johnson
11 min Read
By and large, SQLite is configuration-free. You can get pretty far by just using the default settings. As your application grows and you start tweaking settings, one of the first knobs you’ll come across is the journal mode. This setting determines h
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By Joshua Sierles
11 min Read
We love databases that scale globally. As an ambivalent database provider, we built a global, automated Postgres, and we tinkered with global Redis on scrappy startup weekends. But the Fly.io forecast called for integration over invention. So we part
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By Brad Gessler
2 min Read
Build real-time applications on any backend with Replicache and Fly, run Cron on Fly, two LiveWire how-tos, and learn how Fly reluctantly built its Postgres database service. Ok, it’s been longer than a week since the last update because a lot of us
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By Chris Nicoll & Shaun Davis
18 min Read
Fly.io is an ambivalent database provider—one might even use the word “reluctant”. The reasons for that are interesting, as is the way Fly Postgres works. When we relate this in conversations online, people are often surprised. So we thought we’d tak
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By Dov Alperin
8 min Read
Imagine this: you have invented the best design tool since Figma. But before you can compete with the design-industry heavyweight, you need to be able to compete on one of Figma’s main propositions: real-time collaboration. You do some research and f
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By Brad Gessler
2 min Read
Automatically deploy Elixir apps to production with Github Actions CI and troubleshoot performance issues with OpenTelemetry. Help the Python community draft Django docs. Deploy S3-compatible object storage close to your Fly apps. Last week we got im
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By Brad Gessler
2 min Read
This week Redis gets some power-ups, Elixir confesses its love for React, Fly gets real about Postgres, Livewire gifts us with a few tutorials, and a many of us in North America didn’t have to change the clocks around our house because we convinced ou
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By Chris McCord
13 min Read
It’s hard to overstate the impact React has had since its release in 2013. For me, React came with a few revelations. First was a reactive HTML-aware component model for building UIs. Second was colocated markup directly in the app code. Third, it fo
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By Brad Gessler
3 min Read
Postgres docs improvements First up, some new documentation was created to run people through how to fail over a Postgres database. Performing a Failover Performing a Regional Failover “Getting Started” was updated to show how to setup a Postgres
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By Ben Johnson
12 min Read
Full-stack developers are sleeping on SQLite, a database most devs think more suited to unit tests than production loads. That’s true enough for some apps. Most web apps are read-heavy, though, and we can use that to our advantage. With the right too
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By Dov Alperin
8 min Read
Running a Minecraft server for friends has become an archetypal first foray into the workings of the Internet. For some it’s learning to expose the tender underbelly of a home network to outside connections. For others it’s exploring the world of VMs
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By Ben Johnson
15 min Read
SQL is a weird concept. You write your application in one language, say JavaScript, and then send commands in a completely different language, called SQL, to the database. The database then compiles and optimizes that SQL command, runs it, and return
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By Ben Johnson
14 min Read
If you scour Hacker News & Reddit for advice about databases, some common words of caution are that SQLite doesn’t scale or that it is a single-user database and it’s not appropriate for your web-scale application. Like any folklore, it has some his
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By Lubien & Chris Nicoll
22 min Read
“Remote development environment!” Whether you reacted with a thrill of enthusiasm, a surge of derision or a waft of indifference, we’re not really here to change your mind. That phrase means a lot of different things at this point in history. The m
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By Ben Johnson
14 min Read
When database vendors recite their long list of features, they never enumerate “doesn’t lose your data” as one of those features. It’s just assumed. That’s what a database is supposed to do. However, in reality, the best database vendors tell you exa
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By Chris Nicoll
2 min Read
Fly Volumes are the persistent storage that makes it possible to run full stack apps entirely on the Fly.io platform, keeping your configuration, session or user data in place across deployments. Looking at them from another angle, volumes are space
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By Ben Johnson
14 min Read
Ok, I’ll admit it—I’m a SQLite shill. There are few holes that I don’t try to put a SQLite-shaped peg into. It’s not that I dislike other databases, they’re great. But SQLite is so easy to use and, more importantly, it’s simple. Simplicity leads to r
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By Chris Fidao
1 min Read
Today we’re launching Laravel Bytes - our new home for anything Laravel. We’re excited to support deploying Laravel across the globe - and we have lots to talk about! We’ve already made it easy to run Laravel on Fly, but with the possibilities unlo
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By Chris McCord
18 min Read
LiveView started with a simple itch. I wanted to write dynamic server-rendered applications without writing JavaScript. Think realtime validations on forms, or updating the quantity in a shopping cart. The server would do the work, with the client re
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By The Fly.io Balloon
7 min Read
We have some real gems in this edition. Have you ever wished you could grow the storage volume on a Fly.io app? Now you can!! What about this one: Ever wished that the $99 Pro Plan would include $99 of usage credits? OK, that one may have been a li
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By Thomas Ptacek
25 min Read
If you’re off getting your app up and running on Fly.io and finding your checkbook, great! I won’t get in your way. The rest of you, though, I want to talk to you about what SOC2 is and how it works. Spoiler: the SOC2 Starting Seven post held up pret
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By Will Jordan
20 min Read
Fly.io isn’t a “Gartner Magic Quadrant” kind of company. We use terms like “FaaS” and “PaaS” and “serverless”, but mostly to dunk on them. It’s just not how we think about things. But the rest of the world absolutely does think this way, and I want t
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By The Fly.io Balloon
6 min Read
We’ve had a lot of changelogs about our Phoenix/LiveView-based web UI in recent weeks. It’s pretty rad; we’ve been vocal about being CLI-first, but we love a first-class dashboard. Our dashboard has sprouted a lot of new capabilities, and at this poi
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By Amos Wenger
24 min Read
We have a Rust-based proxy. It was leaking memory. We fixed it, and we’ll talk about that, but to be really thorough, we’ll look at how loading a web page works. Starting with hardware interrupts. The downside of Thomas writing job postings is that t
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By The Fly.io Balloon
3 min Read
Here’s our latest changelog. This week we’re putting the in-browser UI updates a little closer to all the other ones, to see if they’ll play nicely together. [Feature] Our WireGuard peers sync a lot faster with the kernel’s wg state, by adding only
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By The Fly.io Balloon
5 min Read
Here’s our latest changelog. Looking back over the week, our forum community has been quite a driver of (logged) change. When you’re done here, head over there to be a part of it! [Feature] Created an example Node.js app to demonstrate how to expo
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By The Fly.io Balloon
5 min Read
Work leading up to the Fly Machines launch involved a multitude of changes by many of the cogs in this corporate machine, but that’s not to say the other production lines have been idle. For one thing, our web UI has been transforming before our eyes
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By Kurt Mackey
10 min Read
Fly Machines are VMs with a fast REST API that can boot instances in about 300ms. Our proxy can boot Fly Machines for you, and you can shut them down when they’re idle. Which means you can cost-effectively create VMs and keep them standing by to ha
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By The Fly.io Balloon
2 min Read
[Feature] Provisioned new servers in syd, iad, and dfw which were very full. Added capacity should mean customers should no longer get provisioning issues when trying to deploy to these regions. [Feature] The account deactivation page now asks users
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By Ben Johnson
15 min Read
The conventional wisdom of full-stack applications is the n-tier architecture, which is now so common that it’s easy to forget it even has a name. It’s what you’re doing when you run an “application server” like Rails, Django, or Remix alongside a “d
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By Chris Nicoll
5 min Read
Features and fixes are flying like dodgeballs in a school gym, and the Fly.io Changelog Enforcer could probably have done a better job patrolling—but let’s have a look at our haul of updates since our first Logbook post. There’s a fair amount of pr
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By Nolan Darilek
10 min Read
Hey, everyone. Last time we talked a bit about what accessibility is, why it’s important, and how you can incorporate it into your process. Today, using the time-travel superpowers of Git, I’ll take you along as I start making LiveBeats more accessib
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By Chris Nicoll
6 min Read
Here’s a changelog covering our most recent activity (i.e. since we started compiling updates, a bit under two weeks ago): [Feature] Added extra capacity in IAD. [Feature] Backup regions (by far our most confusing misfeature) are now disabled by de
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By Thomas Ptacek
21 min Read
We set the scene, as usual, with sandwiches. Dig if you will the picture: a global Sandwich Bracket application, ascertaining once and for all the greatest sandwich on the planet. Fly.io wants our app, sandwich-bracket, deployed close to users aroun
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By Nolan Darilek
9 min Read
Like every developer, I rely on a number of products and services to manage and promote my many side projects. But I’ve had more than one neat idea go down in flames because I simply couldn’t use the amazing, must-have service that would have made
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By Thomas Ptacek
19 min Read
WireGuard is fundamental to how Fly.io works. Along with Firecracker and Rust, it’s one of the three “interesting” technical choices we’ve made. Practically everything that talks to anything else at Fly.io does so over WireGuard. That goes for use
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By Lubien & Chris Nicoll
8 min Read
In early 2020, before we launched our VM platform, we made a little landing page called Turboku. It was a one-click launcher to deploy a Heroku app on Fly.io. It let people try us out without spending time porting an app. Many of our first customers
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By Chris McCord
12 min Read
We decided that 2022 was a good year to ship a full-stack Phoenix reference app. The “full stack” metaphor has progressed beyond its humble beginnings of some REST endpoints and sprinkles of JS and CSS. Showing off a todo app is also no longer state
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By Kurt Mackey & Chris Nicoll
4 min Read
We like building side projects and also hate paying for hosting for side projects. We also know that y'all like free stuff. And we think that when you use free stuff for side projects, there’s a pretty good chance you’ll pay for similar stuff for rea
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By Lubien
3 min Read
We’ve just introduced a self-service UI for deleting your Fly.io account. From time to time people ask us to deactivate their account. It happens! Maybe you just tried a walkthrough out of interest, or you created a new account with a different name
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By Mark Ericksen
3 min Read
The Livebook launcher was super fun to create. Everything happens in a single LiveView process. There was a problem though… it wasn’t great if we were in the middle of deploying the app for the user and one these things happened: User hits “refresh
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By Chris McCord
3 min Read
Safari 15 shipped in September 2021 and included an obscure CSS bug that broke most LiveView applications. The LiveView client operates in two modes – connected, when it can talk to the server over websockets, and disconnected when offline. When Live
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By Kurt Mackey
18 min Read
Two obvious costs of running Internet apps for users on your own hardware: hardware and bandwidth. We buy big servers and run them in racks at network providers that charge us to route large volumes of traffic using BGP4 Anycast. You probably have at
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By Chris McCord
21 min Read
LiveView strips away layers of abstraction, because it solves both the client and server in a single abstraction. HTTP almost entirely falls away. No more REST. No more JSON. No GraphQL APIs, controllers, serializers, or resolvers. You just write HTM
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By Michael Dwan
6 min Read
We’re working on super fun problems and are looking for more people to join us. In particular: we’re looking for full-stack developers. We expect this will be a good role for early-to-mid-level career developers. Some Background Fly.io’s users intera
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By Thomas Ptacek
29 min Read
This is not really a post about Fly.io, though I’ll talk about us a little up front to set the scene. The last several weeks of my life have been about API security. I’m working on a new permissions system for Fly.io, and did a bunch of researc
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By Mark Ericksen
8 min Read
As a developer, has your manager ever come and asked a question like, “How much money are we making?” If you were a line-of-business developer at a global insurance company, you’d reach for your handy, nosebleed-expensive Business Intelligence (BI) s
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By Mark Ericksen
3 min Read
The Phoenix Framework is the go-to web framework for Elixir developers. A recent PR was merged that replaces the use of node, npm, and webpack with esbuild. For those new to esbuild, it is written in Go so it compiles to native code and runs really f
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By Kurt Mackey
10 min Read
100 milliseconds is the magic number. For a backend application, a sub-100ms response time is effectively instantaneous, and people love using “instant” apps. Since we’re all dirty capitalists, we’d add: if people love your app, you’ll make more mone
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By Mark Ericksen
2 min Read
Livebook 0.2 was released. The big news here was the announcement of “Kino” (meaning “cinema”). It’s a client-side focused feature that animates data changes. José Valim created a video demonstrating some of the new Livebook features. Use this link to
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By Kurt Mackey & Kurt Mackey
13 min Read
This is a story about a cool hack we came up with at Fly. The hack lets you do something pretty ambitious with full-stack applications. What makes it cool is that it’s easy to get your head around, and involves just a couple moving parts, assembled i
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By Alexander Koutmos
9 min Read
Fly.io takes Docker containers and converts them into fleets of Firecracker micro-vms running in racks around the world. If you have a working Docker container, you can run it close to your users, whether they’re in Singapore or Amsterdam, with just
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By Mark Ericksen
6 min Read
Elixir, Erlang, and really just the BEAM has a feature called “Observer”. It’s fun showing it to people new to Elixir because it’s just so cool! It’s a WxWidgets graphical interface that connects in realtime to a running Erlang node and lets you “obs
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By Mark Ericksen
7 min Read
Every application has that core, most important thing that it does. It is the reason the application exists. It’s that central idea that everything else is there to support. A major hurdle for new developers joining a project can be understanding an
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By Thomas Ptacek
11 min Read
We’ve written a bit, for a general audience, about how Fly collects and manages metrics. If you’re just sort of generally interested in metrics and observability, go read that first. Meanwhile, if you’re a Fly user, or considering becoming such a us
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By Thomas Ptacek
13 min Read
We should talk a bit about metrics and measurement and stuff, because they’re how we all know what’s going on. There’s two reasons we’ve written this post. The first is just that we think this stuff is interesting, and that the world can always use
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By Mark Ericksen
8 min Read
One of the best things about building web applications in Elixir is LiveView, the Phoenix Framework feature that makes it easy to create live and responsive web pages without all the layers people normally build. Many great Phoenix LiveView examples
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By Thomas Ptacek
14 min Read
Even though most of our users deliver software to us as Docker containers, we don’t use Docker to run them. Docker is great, but we’re high-density multitenant, and despite strides, Docker’s isolation isn’t strong enough for that. So, instead, we tra
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By Kurt Mackey
14 min Read
The term “CDN” (“content delivery network”) conjures Google-scale companies managing huge racks of hardware, wrangling hundreds of gigabits per second. But CDNs are just web applications. That’s not how we tend to think of them, but that’s all they ar
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By Thomas Ptacek
12 min Read
But Fly is kind of an odd duck. We run hardware in data centers around the world, connected to the Internet via Anycast and to each other with a WireGuard mesh. We take Docker-type containers from users and transmogrify them into Firecracker micro-VM
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By Jerome Gravel-Niquet & Thomas Ptacek & Jerome Gravel-Niquet
12 min Read
If you’ve been keeping up with us at Fly, you may be picking up on a bit of a narrative with us. Fly launched, in the long-long-ago, with a somewhat narrow use case. We took containers from our customers and transmogrified them into fleets of Firecra
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By Jerome Gravel-Niquet
5 min Read
At Fly.io, we run a Rust-based load-balancer which handles almost all of our traffic. It stands on the shoulders of Tokio and Hyper. When the Tokio team announced 0.3 and then 1.0, we figured we’d have to upgrade sooner than later to access related cr
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By Thomas Ptacek & Dj Walker-Morgan & Thomas Ptacek
10 min Read
This is a post about the most dangerous vulnerability most web applications face, one step that we took at Fly to mitigate it, and how you can do the same. Server-side request forgery (SSRF) is application security jargon for “attackers can get you
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By Dj Walker-Morgan
4 min Read
If you missed 2020, lucky you, to get you all caught up, here’s our Previously On Fly segment. Caught up? Good. And now here is the Fly ChangeLog, covering the end of December 2020 to January 2021. 6PN Networking and IPv6 WireGuard VPNs Let your ap
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By Dj Walker-Morgan
4 min Read
TL:DR; Launch, Turboku, Custom Domains, Scaling, One-Click Apps, Persistent Storage, Private Networking and WireGuard VPNs. Fly’s had an unprecedented year, along with everyone else. For us, it was bringing our Application Platform to the world, and
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By Dj Walker-Morgan
1 min Read
There are actually two examples that make up this example. One example is a Websocket-based chat that relays its messages through that NATS cluster. The other part is that NATS cluster, configured as a global messaging cluster that you can install in
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By Thomas Ptacek
16 min Read
Assume for a second we’d like to see what happens when a web page loads in a browser in Singapore. Easy enough; Fly.io will take a container image you throw at it, transform it into a Firecracker VM, and run it in Singapore. Getting Up And Running We
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By Dj Walker-Morgan
2 min Read
The command… It started off as flyctl but we kept being asked when would the command become fly. “Why not both?” we said and now, on most platforms, you can use flyctl or fly interchangeably. Boom! Three keystrokes saved! The current app… You alread
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By Michael Dwan
4 min Read
Fly apps are typically fast to boot, and it’s relatively easy to boot new VMs. We start them up, do some health checks, and then add them to our load balancer and DNS service discovery. But what comes up must go down. We shut VMs down for any number
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By Thomas Ptacek
12 min Read
They say that when you’re starting a product company, it’s a better plan to chase down something a bunch of people will really love a lot than it is to try to build something that everyone will just like a little bit. So when Fly.io launched, it had
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By Kurt Mackey
5 min Read
We first showed Fly.io VMs to developers in early 2020. They were most interested in running CPU intensive apps doing image processing, machine learning predictions, and even video transcoding (despite what were, until recently, offensive bandwidth p
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By Thomas Ptacek
6 min Read
More often than not, modern applications are really ensembles of cooperating services, running independently and transacting with each other over the network. At Fly.io, we’d like it to be not just possible to express these kinds of applications, but
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By Kurt Mackey
5 min Read
When we launched Fly way back in March, we charged $0.085 per GB to send data out from North America and Europe, and $0.14 per GB for Asia Pacific. Our volume has increased dramatically and pushed our unit costs down, so we lowered our prices as of D
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By Dj Walker-Morgan
4 min Read
Example Applications We’ve been focussing on getting more example applications for Fly into your hands. Each guide is complete with a walkthrough of how they were put together so you can see the power of Fly in action. Or you can hop straight to the G
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By Dj Walker-Morgan
2 min Read
The latest additions to our Appkata collection of example apps have landed and they cover how to fit Fly to your selected applications and are some super useful apps anyway. So let’s dive in. Node-RED Ever wanted to be able to dive into your cloud ap
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By Dj Walker-Morgan
4 min Read
To build a modern application, you need to know how to take down your technical challenges in style. It’s a style we call Appkata! Over the coming weeks, we’ll be sharing with you the moves you need to deploy apps onto Fly that let you build faster.
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By Dj Walker-Morgan
3 min Read
Q: I’d like to park my Fly application for a little while so it isn’t consuming resources. How can I do this without destroying the application and redeploying it later? A: As you’ll have noticed, Fly applications stay running all the time ready to
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By Dj Walker-Morgan
2 min Read
Disks in Preview If your application needs to have persistent storage, then the currently in preview volumes feature is for you. The volumes command allows you to create persistent disks for your application. These persist between restarts, deployment
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By Thomas Ptacek
18 min Read
Imagine for a moment that you run a content distribution network for Docker containers. You take arbitrary applications, unmodified, and get them to run on servers close to their users around the world, knitting those servers together with WireGuard.
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By Dj Walker-Morgan
7 min Read
Since Fly launched, we’ve been collecting and managing logs for all the applications running on the Fly platform. It’s a critical but often rarely noted function of the platform. When you type flyctl logs, behind the scenes, there is a lot of comput
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By Dj Walker-Morgan
7 min Read
A Pi-Hole could be the hero of your web connection. It blocks advertising at the roots; the DNS roots that is. By setting up your own Pi-Hole, you can tip all your local network’s requests for known advertising domains down it. What is Pi-Hole? Thin
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By Dj Walker-Morgan
2 min Read
Marathons, long and hard. Personally, I wouldn’t be caught doing one, but I’m always up to help someone who is, especially when I can use a bit of Fly to do it. Steve, our global infrastructure whiz, asked if I could think of a good way to track M
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By Dj Walker-Morgan
5 min Read
Some common requests are addressed this month. One is ‘can you let us type “fly” instead of “flyctl”?’, and it is a shorter command, that is true. Another is can you ‘make updating flyctl easier?’, something we are more than happy to do. And in Septe
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By Dj Walker-Morgan
5 min Read
Heroku supports applications with no apps in them and only add-ons, like Postgres, as a way of providing those services to other applications. As we showed, you can access Heroku Postgres from Fly so it makes it a useful way to get yourself a databa
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By Dj Walker-Morgan
6 min Read
I was recently asked how the database migration in the original Turboku demo worked. For that original demo, the migration was practically automatic. We already knew that you could access a Heroku database from outside Heroku. Since then, Changes in
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By Dj Walker-Morgan
4 min Read
At Fly, you’ll have already discovered that when you create an app, it appears as http://appname.fly.dev and if you connect there, your browser switches automatically, by redirection, to https://appname.fly.dev. That’s how we do it for the fly.dev
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By Dj Walker-Morgan
4 min Read
Q: Is it ok to run non-HTTP apps on Fly? From Pier via community.fly.io A: It is, with one caveat: your applications need to have a network service of some kind. Why is that? Well, when your app deploys, we run health checks to ensure you can connec
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By Dj Walker-Morgan
5 min Read
For the latest version of flyctl, we’ve focussed on making your life fast and simple. From getting your first deployment up and running to setting up a host’s certificate. Builtins First up, we’ve got the new “builtin” builders which you can select w
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By Thomas Ptacek
18 min Read
Workload isolation makes it harder for a vulnerability in one service to compromise every other part of the platform. It has a long history going back to 1990s qmail, and we generally agree that it’s a good, useful thing. Despite a plethora of isola
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By Dj Walker-Morgan
5 min Read
Static websites are great for carrying unchanging content, be it assets, images, fonts or even, as in this case, an entire site. Well, I say entire site, but if you saw my last article, you’ll know I recently rebranded a Maker organization and needed
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By Dj Walker-Morgan
8 min Read
There I was wondering what to do about a website for a new community venture I was running where I thought, yes, let’s generate the site with Hugo, serve it with Caddy and run it all on Fly. Why Hugo and Caddy? Well, they both have good reputations as
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By Dj Walker-Morgan
4 min Read
This flyctl release brings in some big changes in the command structure as we move to an app-centric command style. What does that mean? Well, the apps subcommand is being deprecated; we’ve kept it in place for this release but now all its commands h
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By Kurt Mackey
1 min Read
I’m a newly minted GraphQL convert. We built Fly on top of GraphQL and the experience turned me into a shameless cheerleader. An API format with static typing? That’s my jam. (If you don’t care for JAMStack puns you can just go read our guide on bui
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By Thomas Ptacek
14 min Read
It’s been a hectic first couple of weeks at Fly, and I’m writing things up as I go along, because if I have to learn, so do you. This is going to be a bit of a meander; you’ll have to deal. Let’s start with “what’s Fly?” Briefly: Fly is a content del
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By Dj Walker-Morgan
5 min Read
Say hello to --json or -j for short. This new flag attempts to present all output from flyctl as JSON. If a command queries the Fly GraphQL API, you’ll get the JSON data from that call in your output. If a command shows you logs, you’ll get the logs
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By Dj Walker-Morgan
3 min Read
In this edition: a new way to install flyctl (and native Windows installers), new commands in flyctl that let you restart, list and monitor applications, an improved open command and an important update to the Deno Buildpack. Flyctl New instruction
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By Dj Walker-Morgan
1 min Read
You can get the Changelog in the blog or through an RSS feed of just changelog updates available on fly.io/changelog.xml. There’s also a dedicated ChangeLog page with all the recent updates. Most of this week’s changelog items are covered in an recen
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By Dj Walker-Morgan
2 min Read
What’s a pause for? When you start building your applications, there may come a point where you don’t want to keep your application running - mothballing while another project happens, schedule delays, or just plain wanting to manage your costs. Tha
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By Dj Walker-Morgan
8 min Read
WebSockets are powerful things for creating interactive applications. Example Zero for WebSocket examples is the chat application. This leverages WebSockets’ ability to keep a connection alive over a long period of time while bidirectionally passing
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By Dylan Jhaveri
4 min Read
Wocket (WebSocket to RTMP) This project is a proof-of-concept to demonstrate how you can stream live from your browser to an RTMP server. Streaming via RTMP is how you stream to Twitch, Youtube Live, Facebook Live, and other live streaming platforms
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By Dj Walker-Morgan
1 min Read
Since the last ChangeLog, we implemented a whole new scaling system with updates to the platform and flyctl. You can read all the details in the Updating Scale article. We’ve also been improving the performance of our backhaul, which moves traffice b
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By Dj Walker-Morgan
6 min Read
We’ve been working with Deno for Fly for a while and its great blend of TypeScript, V8, Rust and simplicity makes for a great app experience. And great apps deserve a great deployment. We enjoy Deno so much that when we brought out our first cloud na
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By Dj Walker-Morgan
5 min Read
We have been recently looking at how scaling commands work on Fly and we’ve come up with a new system with a simpler model and more compact command set to work with. We’d like to introduce it to you today. The Scaling System Previously, at least in t
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By Dj Walker-Morgan
1 min Read
Since the last ChangeLog, we’ve introduced some enhancements to flyctl which make it easier to deploy tagged local and remote images directly to Fly. There is also a new load-balancing algorithm in operation which should be more effective with widely
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By Dj Walker-Morgan
8 min Read
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By Dj Walker-Morgan
1 min Read
Warning: This document is old! It is likely wrong in some important way. The folks behind Imaginary have worked with Fly and they also added the one-click launcher to their README on GitHub so that potential Imaginary users can be up, converting, res
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By Dj Walker-Morgan
1 min Read
This past week has been one focused on the Fly infrastructure with earlier certificate renewals now in place and a dedicated Changlog page. We also made time to bring in some user contributed changes to the flyctl which make debugging fly.toml file
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By Dj Walker-Morgan
1 min Read
7th April 2020 FlyCtl – v0.0.115 released Buildkit support. Setting environment variable DOCKER_BUILDKIT to 1 will enable use of the v2 buildkit backend which performs async parallel builds. For compatibility, DOCKER_BUILDKIT defaults to 0. The -
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By Dj Walker-Morgan
3 min Read
Identifying your build When you deploy, the flyctl application looks for instructions to build the image in a Dockerfile or creates a builder VM to do the image build. Let’s start with the flags that control where flyctl looks for things. -c, –confi
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By Dj Walker-Morgan
3 min Read
Q: What if I get a large number of malicious TCP connections from around the world that are malicious and cause a large number of apps to be launched in the various datacenters. Are we on the hook for the bill? And is there anything in place to stop
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By Dj Walker-Morgan
9 min Read
I’ve always liked finding a good dataset. With a background in databases and writing, I know a good dataset can bring a demo to life, be it a census of Squirrels in Central Park or a survey of grocery purchases in London. Datasets can also provide va
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By Dj Walker-Morgan
4 min Read
Starting with Continuous Deployment to Fly To deploy to Fly you essentially need four things The application you want to deploy. A runnable copy of flyctl. A fly.toml file. Your Fly API Token. For this example, we’ll deploy hellofly, our small Go
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By Dj Walker-Morgan
4 min Read
Q: Can I set up a custom hostname or domain with Fly? A: You can. In fact you can set up as many of them on an application as you like. When you create a custom hostname on Fly and validate it, you also get Let’s Encrypt certificates automatically. Yo
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By Dj Walker-Morgan
4 min Read
Update 15/May/2020: The contents of this article have been superceded by a new scaling system on Fly. We’ve refined the scaling models and commands to make things simpler to use. To read about these changes see the article on the updated scale system
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By Dj Walker-Morgan
2 min Read
In Custom Domains with Fly, you’ll learn how to configure an NGINX server to proxy traffic to external sites and how to attach host and domain names to your Fly applications using Fly’s command line flyctl. For those of you who practice devops and
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By Dj Walker-Morgan
1 min Read
This week with Fly: We show you how to use Fly to build your own GraphQL APIs. Firefox is switching DNS over HTTPS (DoH) on by default in the USA. We already have a great guide to using Fly as your private DoH service. Fly’s new community portal for
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By Dj Walker-Morgan
1 min Read
Hasura gives you an open source GraphQL backend which can make it simple to query PostgreSQL by helping you map all your schemas and roles. It also rolls in the ability to query other GraphQL services so you can mix in services. With an interactive c
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By Dj Walker-Morgan
1 min Read
We deployed Docker’s official httpd image in our first Fly Friday video. That image, when run, serves up files from its /usr/local/apache2/html. By default the image contains the words “It works”. If we want it to say something else, we need to copy
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By Dj Walker-Morgan
1 min Read
TL;DR: The -p flag is used with flyctl apps create when you create a Fly app for the first time. Setting -p with a numeric value automatically sets the internal port of the generated fly.toml configuration file. The internal port is the port your a
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By Dj Walker-Morgan
2 min Read
A Speedrun for everyone Let’s get straight down to it. Make sure you have the latest version of flyctl and then get a Node application like this version of our hello world example - “hellonode-builder”. Wrap text
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By Dj Walker-Morgan
2 min Read
The next question is how can they move their application the Fly. For that we’ve created “Turboku”, a simple way to bring your Heroku apps to Fly. What we do is take your Heroku web dynos and turn them into Fly applications automatically. That
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By Dj Walker-Morgan
3 min Read
Why Command Lines? As we’ve developed Fly, we’ve seen numerous benefits that come from driving the service through the command line. Our newest addition to our command armory is the flyctl command which now, quite literally, covers the entire lifecycl
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By Dj Walker-Morgan
<1 min Read
Check out our all new documentation for the Fly platform which covers everything from creating Apps you can deploy to Fly to how to take existing Docker images and setting them free across the globe. If you have any questions, drop a line to us on su
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