---
title: "Phoenix.new – The Remote AI Runtime for Phoenix"
description: "Phoenix.new is presented as a batteries-included, fully online coding agent designed for Elixir and Phoenix, after an initial weekend project grew into a system that generated Phoenix applications and drove an in-browser IDE. It runs in an ephemeral Fly Machine, giving the agent and user a shared root shell while isolating local machines; applications launch in the cloud with preview URLs, GitHub integration, and Fly.io infrastructure guardrails. A headless Chrome browser lets the agent inspect page content and JavaScript state, interact with front ends, and correlate changes with server-side logs while testing applications. The system already handles full-stack applications using WebSockets, Phoenix Presence, and real databases, can work with other installed languages and frameworks, and is being used to triage GitHub issues and produce pull requests asynchronously."
---

# Phoenix.new – The Remote AI Runtime for Phoenix

[Fly.io](https://yomu.fyi/company/fly-io) · Jun 20, 2025

**Type:** Announcement

## Summary

Phoenix.new is presented as a batteries-included, fully online coding agent designed for Elixir and Phoenix, after an initial weekend project grew into a system that generated Phoenix applications and drove an in-browser IDE. It runs in an ephemeral Fly Machine, giving the agent and user a shared root shell while isolating local machines; applications launch in the cloud with preview URLs, GitHub integration, and Fly.io infrastructure guardrails. A headless Chrome browser lets the agent inspect page content and JavaScript state, interact with front ends, and correlate changes with server-side logs while testing applications. The system already handles full-stack applications using WebSockets, Phoenix Presence, and real databases, can work with other installed languages and frameworks, and is being used to triage GitHub issues and produce pull requests asynchronously.

## Context

The project began to make LLM agents work with Elixir as well as Python and JavaScript. It also targets the tedious work of getting agent-built applications online, which is described as potentially taking much longer than writing the code.

## Approach / What changed

Phoenix.new combines a shared root shell in an isolated, ephemeral Fly Machine with cloud deployment, preview URLs, GitHub integration, and Fly.io infrastructure guardrails. Its agent can drive a headless Chrome browser, inspect page content and JavaScript state, read server logs, run tests, and interact with applications.

## Takeaways

- Each session provides the user and agent a shared root shell in an ephemeral Fly Machine, allowing package and operating-system changes without affecting the local machine.
- The headless Chrome integration lets the agent test front-end changes against real page content and JavaScript state, rather than relying only on screenshots or compilation and linting.
- Phoenix.new can build applications with WebSockets, Phoenix Presence, and real databases, and supports asynchronous work such as triaging GitHub issues and producing pull requests.

**Tags:** [AI Agents](https://yomu.fyi/topic/ai-agents), [Elixir](https://yomu.fyi/topic/elixir), [Fly Machines](https://yomu.fyi/topic/fly-machines)

- Source: [Fly.io](https://fly.io/blog/phoenix-new-the-remote-ai-runtime)
- Source URL: https://fly.io/blog/phoenix-new-the-remote-ai-runtime
- Ingested by Yomu: 2026-09-02T11:59:03.360Z

[Read original post](https://fly.io/blog/phoenix-new-the-remote-ai-runtime)