Background Agent on Railway

This is the companion repo for "I Built a Remote Coding Agent Platform on Railway (OpenCode, Claude Code, Codex) " (a video I created in partnership with Railway).

It is a full-stack demo that provisions AI agents into sandbox sessions running on Railway. (inspired by Ramp's internal agent "Inspect")

Deployment Template!

Video Progression:

1. Run opencode locally
2. Run opencode inside a container
3. Deploy to Railway
4. Add code-server to container image
5. Use the Railway API to deploy
6. Create a custom API for the control plane
7. Add a frontend (+ add proxy)
8. Install other coding agents
9. Configure GitHub access and pre-clone the repo

Development Notes

Project structure

• packages/api: Express + TypeScript API, Railway integration, session management, and proxying.
• packages/web: React + Vite frontend.
• packages/sandbox: Sandbox container image used by session environments.
• docker-compose.yml: Local API + Postgres + sandbox containers for development.

Prerequisites

• Mise
• Docker + Docker Compose

Local development

1. Start local infra:

   docker compose up -d

2. Configure API environment variables:

   cp packages/api/.env.example packages/api/.env

3. Install dependencies:

   pnpm install --dir packages/api
   pnpm install --dir packages/web

4. Run API and web app in separate terminals:

   pnpm --dir packages/api dev
   pnpm --dir packages/web dev

The API runs on http://localhost:3000 and the web app runs on http://localhost:5173.

Useful API commands

pnpm --dir packages/api db:generate
pnpm --dir packages/api db:migrate
pnpm --dir packages/api build
pnpm --dir packages/api start

Useful web commands

pnpm --dir packages/web build
pnpm --dir packages/web preview