One developer. One problem. One tool.
OpenAPI Studio started as a migration. The original project — openapi-gui — was a Vue 2 + jQuery + Express app for editing OpenAPI specs. It worked, but it had limits: no collaboration, specs stuck in localStorage, a dated UI, and an architecture that made changes painful.
The rewrite started from scratch with Astro 5, React 19, and Cloudflare. The goal wasn't just to port the old editor — it was to build the tool that should have existed all along: a visual flow builder for understanding API structure, team workspaces for collaboration, built-in API execution for testing, and public hotlinks for sharing.
This is a solo developer project. One person, building in the open, shipping weekly. The codebase is public, the roadmap is transparent, and the free tier is genuinely free — not a trial, not a teaser.
Design principles
Four rules that guide every decision
Do one thing well
We edit OpenAPI specs. That's it. No API gateway, no monitoring, no documentation hosting. Just the editor, done right.
Respect developer time
Fast load, auto-save, instant format conversion. No bloat, no upsell modals, no surprise paywall.
Don't charge for basics
The free tier has everything a solo developer needs. Unlimited specs, full editor, API execution, public hotlinks.
Show the code
GitHub public, documented, self-hostable. No black box. No vendor lock-in. Deploy it on your own Cloudflare account.
Under the hood
Modern stack, zero legacy
| Technology | Purpose |
|---|---|
| Astro 5 | Framework — SSR with island architecture |
| React 19 | Interactive islands (editor, flow builder) |
| @xyflow/react | Flow visualization — path tree graph |
| ELK.js | Graph layout algorithms — 4 modes |
| Cloudflare Pages | Edge hosting — global deployment |
| Cloudflare D1 | SQLite database — serverless |
| Cloudflare KV | Edge cache — hotlink serving |
| Cloudflare R2 | Blob storage — large exports |
| Tailwind CSS 4 | Utility-first styling |
| nanostores | Shared state across islands |
| Drizzle ORM | Type-safe database queries |
| Zod | Input validation at system boundaries |
| Vitest | Unit and integration testing |
Architecture
How the pieces fit together
Get in touch
OpenAPI Studio is built in the open. Found a bug? Have a feature request? Open an issue.