Forge-sim: a local Forge runtime for testing, AI agents, and local dev

Hey everyone, wanted to share the first public release of some tooling I’ve built for Forge.

It’s a simulated Forge runtime that runs your app locally with no cloud deploy. There are three ways to use it:

  • A test library for running Automated Tests. Designed specifically for CI/CD testing. Headless UIKit2 rendering, shims for most forge APIs. Drop-in configurations for vitest and jest.
  • A CLI and stdio MCP server for AI driven development that deploys and tests against a sandboxed, simulated runtime.
  • A development server that serves your app locally for more traditional browser driven development and testing.

I originally built it for a fairly complex Forge app I got tired of redeploying to Atlassian’s cloud to test the smallest change. Then I decided to build out the tool to be more general purpose. There is a lot of surface to the Forge platform, so please let me know if you try it out and run into any problems.

This is a personal project. I don’t work for Atlassian and this project is not affiliated with Atlassian in any way.

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