---
title: "Fly.io"
description: "45 posts about Fly.io, summarised, each linking to the original."
---

# Fly.io
> 45 posts about Fly.io, summarised, each linking to the original.

## Articles

### [32 Bit Real Estate](https://yomu.fyi/post/32-bit-real-estate.md)
- Company: [Fly.io](https://yomu.fyi/company/fly-io.md)
- Published: Oct 18, 2021
- Type: Explainer

Fly.io’s globally distributed network needs routable IPv4 addresses because it assigns distinct public addresses to applications, including non-HTTP services such as UDP DNS servers and TCP game servers. The post explains how address control depends on Regional Internet Registry transfers, a BGP4 ASN, upstream peering, and advertising the same address from multiple locations for Anycast routing. IPv6 and TLS SNI can reduce address demand, but IPv6 connectivity remains unreliable for many users and SNI does not cover non-TLS applications; keeping separate provisioning paths is also considered undesirable. IPv4 blocks are therefore bundled with apps, while outright acquisition is preferred to leasing because addresses can remain assigned indefinitely, despite future IPv6 obsolescence and the risk that their value could eventually fall to zero.


### [Fly.io Is Hiring Full-Stack Developers](https://yomu.fyi/post/fly-io-is-hiring-full-stack-developers.md)
- Company: [Fly.io](https://yomu.fyi/company/fly-io.md)
- Published: Sep 1, 2021
- Type: Announcement

Fly.io is seeking early-to-mid-level full-stack developers to work on customer-facing parts of its global application-hosting product. The role sits in a CLI-first organization whose UX stack combines Rails, GraphQL, and Go, with more Elixir and Phoenix planned, while the broader platform uses Rust and Go. Candidates are not expected to be Rails or Elixir experts; the stated bar is the ability to learn unfamiliar code and produce work that holds up, including deploying an application end to end and building browser UI components. Hiring centers on untimed work-sample challenges based on the team’s actual work rather than resume screening, interview gauntlets, or gotchas. The remote full-time role offers US healthcare, flexible vacation, hardware and phone allowances, and $120k–$140k plus equity.


### [Monitoring Elixir Apps on Fly.io With Prometheus and PromEx](https://yomu.fyi/post/monitoring-elixir-apps-on-fly-io-with-prometheus-and-promex.md)
- Company: [Fly.io](https://yomu.fyi/company/fly-io.md)
- Published: Jun 28, 2021
- Type: Tutorial

Monitoring Elixir applications on Fly.io, the post presents a way to add production visibility without administering a Prometheus instance. Fly.io’s managed service scrapes an application’s metrics endpoint at a configured interval, with fly.toml specifying the port and path; Prometheus stores the resulting time-series snapshots and Grafana queries them with PromQL. PromEx supplies Elixir instrumentation through plugins for components such as the application, BEAM, Phoenix, Ecto, and Phoenix LiveView, while optionally uploading dashboards and annotating application lifecycle events through Grafana’s HTTP API. The example enables Fly.io metrics on port 4000 at /metrics and configures PromEx dashboards for a Todo List application. The stated result is an instrumented application with dashboards and annotations in minutes, while monitoring can also support rollback decisions, stress-test analysis, prioritization, and capacity planning.


### [Observing Elixir in Production](https://yomu.fyi/post/observing-elixir-in-production.md)
- Company: [Fly.io](https://yomu.fyi/company/fly-io.md)
- Published: Jun 14, 2021
- Type: Tutorial

Observer, included with Elixir and Erlang’s BEAM, is a WxWidgets interface that connects in real time to running nodes, showing process trees and state while allowing processes to be killed. This guide uses Fly.io to connect a local Observer to production nodes through a release cookie, a WireGuard tunnel, and a helper script. The example is a multi-region Tic-Tac-Toe application in Frankfurt and Los Angeles; a local IEx session joins the remote cluster, and Observer can connect to either node. Inspecting a live game exposes its GenServer state in Erlang representation. Killing its process immediately starts a replacement with a different PID and leaves other games running, but recovery still requires the player to reload the page or restart game joining.


### [Building a Distributed Turn-Based Game System in Elixir](https://yomu.fyi/post/building-a-distributed-turn-based-game-system-in-elixir.md)
- Company: [Fly.io](https://yomu.fyi/company/fly-io.md)
- Published: Apr 29, 2021
- Type: Tutorial

Mark Ericksen describes building a proof-of-concept distributed, clustered game system for turn-based multiplayer applications with Elixir and Phoenix LiveView. Rather than separate JavaScript and API layers or external state systems such as Kafka and Redis, the design uses server-rendered HTML over websockets, Phoenix.PubSub, and Horde’s distributed process registry. A player’s LiveView sends moves to a GameServer, which publishes updated game state so subscribed LiveViews re-render for every connected player; Tic-Tac-Toe supplies the model. Hosted on Fly.io, geographically close web servers connect over a private WireGuard network while a game’s single GameServer remains the source of truth, with libcluster handling cluster formation and healing. The resulting open-source proof of concept supports multiplayer games, four-letter game codes, on-demand creation, responsive updates, and globally clustered servers.


### [Building clusters with serf, my new favorite thing](https://yomu.fyi/post/building-clusters-with-serf-my-new-favorite-thing.md)
- Company: [Fly.io](https://yomu.fyi/company/fly-io.md)
- Published: Jan 14, 2021
- Type: Problem & solution

The post builds a geographically distributed Headless Chromium cluster on Fly.io and uses it to examine the limits of DNS-based service discovery. It first deploys Chromium in a Singapore Firecracker VM, secures Chrome Debug Protocol access by enabling Fly's private 6PN network and connecting through WireGuard, then scales instances across Singapore, Sydney, Paris, and Chile. Because DNS provides only snapshots and no convenient change notifications, each node runs a leaderless Serf agent bound to its private IPv6 address, tags members by role and region, and joins peers discovered through internal DNS. Serf then supplies an up-to-date membership map, RTT and Vivaldi-based nearness information, plus events and queries; the post concludes that it is simpler than Consul or Zookeeper and more capable than DNS for this setup.


### [Get fly with your Fly command line](https://yomu.fyi/post/get-fly-with-your-fly-command-line.md)
- Company: [Fly.io](https://yomu.fyi/company/fly-io.md)
- Published: Jan 5, 2021
- Type: Tutorial

Fly’s command-line tool, available as both flyctl and fly on most platforms, includes shortcuts and options that reduce directory changes and browser navigation. App selection can use -a appname instead of relying on the current directory’s fly.toml; fly deploy can also build from a specified child directory, such as ./mygreatchildapp. When a fly.toml is present, the command asks for confirmation that the supplied app name should be used. Multiple deployment variants can be kept in separately named configuration files and selected with -c or --config, including when deploying from a monorepo tree. Browser-oriented commands include fly open for an app’s .fly.dev URL, fly dash metrics for dashboard metrics, and fly docs for the documentation’s top page.


### [We cut bandwidth prices. Go nuts.](https://yomu.fyi/post/we-cut-bandwidth-prices-go-nuts.md)
- Company: [Fly.io](https://yomu.fyi/company/fly-io.md)
- Published: Dec 3, 2020
- Type: Announcement

Fly.io announces lower outbound data-transfer pricing for apps running in its Firecracker VMs: $0.02 per GB from North America and Europe, and $0.04 per GB almost everywhere else. The December 1, 2020 change follows dramatically increased volume, reducing bandwidth costs by 75% from the March launch prices of $0.085 per GB in North America and Europe and $0.14 in Asia Pacific. Rather than use graduated tiers or regional rates, Fly.io uses one blended price for all customers, accepting that some traffic is more expensive and some use cases may pay too much. A 70% target margin underpins the model, while a 160GB monthly free allowance covers low-volume projects; India is an exception at $0.12 per GB, and large-transfer customers can request lower prices if they commit to substantial monthly usage.


### [Appkata - Example Apps on Fly](https://yomu.fyi/post/appkata-example-apps-on-fly.md)
- Company: [Fly.io](https://yomu.fyi/company/fly-io.md)
- Published: Nov 18, 2020
- Type: Tutorial

Appkata introduces four example backend apps for Fly, intended to show how to deploy common services while learning the platform’s deployment patterns. The examples cover Redis as a customizable, volume-backed key/value database; MinIO as a single-node, S3-compatible object store exposed through Fly’s TLS edge connections; Gogs as a private Git server using SQLite3 and Fly volumes; and Mosquitto as an MQTT broker with TLS, username/password authentication, and volume-backed message persistence. The examples emphasize adapting existing Docker images, attaching persistent storage, and exposing services securely. The post presents these as an initial set that will expand over the following weeks, alongside a Fly Community site for questions and guidance.


### [Fly Answers Questions - Suspend, Resume, Restart and Redis](https://yomu.fyi/post/fly-answers-questions-suspend-resume-restart-and-redis.md)
- Company: [Fly.io](https://yomu.fyi/company/fly-io.md)
- Published: Oct 30, 2020
- Type: Explainer

Fly’s answers clarify how to stop an application temporarily, restart instances, configure minimum capacity, use Redis, and invoke the CLI. The fly suspend command reduces an app’s instance count to zero while preserving its status and settings; fly resume first restores one instance, checks it, and then redeploys from the previous configuration. By contrast, fly restart restarts each instance in place without triggering a deployment, while applications cannot set a minimum instance count of zero except by suspending. Fly’s Redis implementation does not support Pub/Sub, scripting, or Geo commands, and flyctl now creates a symlink to the shorter fly command as migration toward the latter continues with script compatibility in mind.


### [The October Fly Changelog: Preview Disks and DNS and Better Builtins](https://yomu.fyi/post/the-october-fly-changelog-preview-disks-and-dns-and-better-builtins.md)
- Company: [Fly.io](https://yomu.fyi/company/fly-io.md)
- Published: Oct 27, 2020
- Type: Announcement

The October Fly changelog records platform and CLI updates, centered on preview persistent disks, configurable builtins, environment-variable configuration, and status monitoring. The new volumes commands let Fly applications create persistent disks whose data survives restarts, deployments, and suspension; the feature remains in preview. Applications can now set environment variables in fly.toml instead of using the secrets feature, while builtin settings expose controls such as Deno permissions and HTTPS auto-upgrading and logging for the static web server. flyctl 0.0.145 also adds Python/Procfile builtin support, a --watch status mode that polls every five seconds, a --rate option, default-org selection in init, and fixes for token checks and wildcard certificate domains.


### [Flyctl Builtins - The Fly Changelog for August](https://yomu.fyi/post/flyctl-builtins-the-fly-changelog-for-august.md)
- Company: [Fly.io](https://yomu.fyi/company/fly-io.md)
- Published: Aug 26, 2020
- Type: Announcement

Flyctl v0.0.139 adds built-in builders for Node, Ruby, Deno, Go, and static web servers, allowing an app to be initialized and deployed without a Dockerfile. The release also lets flyctl init select a public Docker image, stores that choice in fly.toml, and supports repeatable image builds with configurable ports and health checks. Region visibility improves through backup-region listings and a (b) marker in flyctl status, while guided certificate creation supplies DNS instructions for traffic direction and ownership verification. Additional changes include --import, --local-only, timestamped JSON status output, orgs and dns commands, and clearer deployment and authentication messaging. The changelog notes that orgs and dns remain works in progress, and version 0.0.139 fixes an issue with builtin init.


### [Serve small with Fly.io and GoStatic](https://yomu.fyi/post/serve-small-with-fly-io-and-gostatic.md)
- Company: [Fly.io](https://yomu.fyi/company/fly-io.md)
- Published: Jul 27, 2020
- Type: Tutorial

The post shows how to deploy a tiny static signpost site on Fly.io using GoStatic, with the aim of keeping the application’s footprint and running cost low. GoStatic is a self-contained web server that can run in a bare Docker image; the described image is 6MB, while the completed deployment reports 7.7MB. The setup uses fly init examplegostatic -p 8043, a two-line Dockerfile based on pierrezemb/gostatic, and an index.html copied to /srv/http/index.html; Fly routes ports 80 and 443 to GoStatic’s port 8043 and provides HTTPS. After deployment reaches one healthy instance, the post reduces the default micro-2x VM from 512MB RAM to micro-1x, which provides 128MB. This matches the small workload and is presented as a way to reduce running costs.


### [Flyctl Evolved - Fly Changelog](https://yomu.fyi/post/flyctl-evolved-fly-changelog.md)
- Company: [Fly.io](https://yomu.fyi/company/fly-io.md)
- Published: Jul 10, 2020
- Type: Announcement

Flyctl v0.0.137 introduces an app-centric command structure while deprecating the apps subcommand, whose operations now have top-level equivalents such as init, destroy, move, restart, resume, suspend, and list apps. The release changes move, restart, resume, suspend, and status to accept an app name as a final argument, while retaining status -a; list also gains app-name fragments and status or organization filters, and list orgs shows accessible organizations. The init flow offers builders or Dockerfile use, can generate a simple hello-world deployment, and supports --dockerfile to skip the builder query, while info and version gain scripting-oriented output controls. Secret changes block operations on suspended deployments and can monitor deployments unless --detach is used. Platform fixes concatenate multiple HTTP/2 cookie headers during HTTP/1 downcasting, add Via headers to requests and responses, and improve deployment image optimization.


### [Run Apollo Server Close to Your Users](https://yomu.fyi/post/run-apollo-server-close-to-your-users.md)
- Company: [Fly.io](https://yomu.fyi/company/fly-io.md)
- Published: Jul 1, 2020
- Type: Tutorial

Run Apollo Server Close to Your Users presents an edge deployment pattern for GraphQL APIs. The post argues that, much like serving JavaScript and markup from a CDN, placing API servers and an application cache near users can improve application speed. Its approach combines Fly.io’s platform for running API servers close to users with a global Redis cache service, then uses Apollo Server’s cache capabilities and first-class Redis support. A demo GraphQL API built from the Open Library REST API accompanies the guide, with both a guide and source code available. The author frames the design through a newly adopted GraphQL perspective, emphasizing static typing and describing the resulting setup as CDN-like infrastructure for an API.


### [Fly Changelog for 9th June](https://yomu.fyi/post/fly-changelog-for-9th-june.md)
- Company: [Fly.io](https://yomu.fyi/company/fly-io.md)
- Published: Jun 9, 2020
- Type: Announcement

The 9th June Fly Changelog describes updates to flyctl, Fly platform tooling, and related web sites, centered on installation, application management, monitoring, and Deno builds. New installation instructions support macOS and Linux through a shell script, while a PowerShell command provides native Windows installation and flyctl now installs under $HOME/.fly/bin or configured $FLYCTL\_INSTALL/bin. New commands let users restart applications, list accessible apps and organizations with text, organization, and status filters, or resume deployment monitoring with flyctl monitor. The open command accepts a URL path, secret updates automatically start monitoring for redeployment, and upgrade messages move to stderr for CI tooling. The Deno Buildpack now reads configuration from a required .config file, which also allows selecting the Deno version; an empty file is valid, while its absence produces an explanatory error.


### [WebSockets and Fly](https://yomu.fyi/post/websockets-and-fly.md)
- Company: [Fly.io](https://yomu.fyi/company/fly-io.md)
- Published: May 20, 2020
- Type: Tutorial

Fly supports WebSocket connections, and the post demonstrates that support with flychat-ws, a small chat application built from raw WebSockets and Express. Deployment requires cloning the example, running npm install, then using flyctl init, flyctl deploy, and flyctl open, with no application-specific configuration changes. Its fly.toml maps internal TCP port 8080 to HTTP port 80 and TLS/HTTP port 443, sets concurrency limits of 20 soft and 25 hard, and checks the service every 10 seconds with a two-second timeout. The Node server broadcasts each received message to every connected client, while the browser selects ws or wss from the served protocol and sends JSON messages. TLS terminates at Fly’s network edge, and the app can also run locally or in Docker.


### [Mux, Fly, Wocket and RTMP](https://yomu.fyi/post/mux-fly-wocket-and-rtmp.md)
- Company: [Fly.io](https://yomu.fyi/company/fly-io.md)
- Published: May 19, 2020
- Type: Tutorial

Wocket is a proof-of-concept application for sending live video from a browser to an RTMP server, potentially avoiding a local encoder such as OBS or Ecamm Live. Built with Next.js and a custom WebSocket server, it captures webcam video, renders it onto a canvas, and uses ffmpeg to support streaming to a Mux live stream through an RTMP ingest URL. The post documents local setup with npm, production commands, and deployment to Fly.io via flyctl and a Dockerfile, while noting that ffmpeg must be available on the PATH. The intended integration uses the MediaRecorder API to send video when dataavailable fires. Mux test streams are limited to five minutes, watermarked, and deleted after 24 hours when no credit card is entered, and the author cautions against relying on the demo for important production workloads.


### [Fly Changelog May 15th 2020](https://yomu.fyi/post/fly-changelog-may-15th-2020.md)
- Company: [Fly.io](https://yomu.fyi/company/fly-io.md)
- Published: May 15, 2020
- Type: Announcement

Fly’s May 15, 2020 changelog records changes to the Fly platform, flyctl, and related websites since the previous update. The main release was a new scaling system based on region pools, accompanied by new scaling commands in flyctl 0.0.122; the earlier autoscale command from version 0.0.121 was removed. The platform also rolled out an HTTP2-only backhaul for traffic between the Fly edge and datacenters, with the changelog reporting improved performance and stability for applications using the http handler. Other entries document new autoscale and regions commands in 0.0.121, consistent naming for flyctl binary artifacts, removal of references to 32-bit Windows and Linux builds during deprecation, and a fix for custom Dockerfile mapping.


### [Updating Scale](https://yomu.fyi/post/updating-scale.md)
- Company: [Fly.io](https://yomu.fyi/company/fly-io.md)
- Published: May 13, 2020
- Type: Announcement

Fly introduces a new scaling model and command set intended to simplify how applications distribute instances across regions and manage global load. Instead of assigning instance counts to a fixed regional list, the system uses a pool of allowed regions plus global minimum and maximum instance counts, with Standard and Balanced models determining placement. Standard distributes instances evenly through the minimum and adds demand-driven instances without relocating them, while Balanced can move instances from other regions once the maximum is reached to match regional demand. The new flyctl regions command manages the pool, and flyctl scale show, standard, balanced, set, and vm commands configure or inspect scaling mode, counts, and VM size. Regional allocation can still fall back to a nearby region when the selected region cannot create an instance.


[Newer posts](https://yomu.fyi/topic/fly-io.md) · [Older posts](https://yomu.fyi/topic/fly-io/page/3.md)