Playground
Fast, built-in REST API client with zero CORS errors, persistent draft sessions, folder organization, and native Rust execution.
Testing your APIs shouldn't require launching a heavy external app, signing up for an account, or bumping into monthly subscription limits.
The Playground is Proxync's built-in REST API studio. It gives you a clean, intuitive interface to build requests, inspect JSON responses, organize endpoints into folders, and test your backend—with zero setup friction.
Why you'll never see a CORS error in Playground:
Have you ever tried testing an API from a web browser tool, only to be blocked by a redCORS policyerror? Browser extensions and web apps are subject to strict browser cross-origin rules. Because Playground runs natively inside Proxync's desktop engine, your requests run directly on your operating system with zero CORS blocks.
Why Developers & Vibe Coders Love Playground
- Runs 100% Offline & Private: Your API keys, headers, and request bodies never touch any third-party cloud.
- Persistent Drafts: If you restart Proxync or reboot your computer, your open tabs, unsaved drafts, and recent responses are preserved automatically.
- Target Route Badges: Next to the Send button, a dynamic badge shows where your request is going:
Local Loopback— Sent directly to your local port (localhost:3000).Proxync Native— Routed through your high-speed SSH tunnel (relay.proxync.dev).Cloudflare Edge— Routed through your public Cloudflare tunnel.
- Right-Click Context Menus: Easily rename, duplicate, copy URL, or delete saved requests in your collection sidebar.
- Built-in Decompression: Supports automatic
gzip,brotli, anddeflatedecompression so payloads always display as readable JSON or text.
Where Requests Come From
You can populate your Playground collections in four convenient ways:
| Source | How It Works |
|---|---|
| Manual Builder | Click + New Request to type an endpoint URL, pick an HTTP method, and set headers. |
| Sent from Traffic | Click Send to Playground on any item in the Traffic Inspector to inspect real webhooks. |
| Auto-Scanned Codebase | Proxync's route scanner detects endpoints in Next.js, FastAPI, or Express projects automatically. |
| OpenAPI / Swagger Import | Import an existing OpenAPI YAML or JSON file to populate a complete collection instantly. |
Keyboard Shortcuts
Work faster with convenient keyboard shortcuts:
| Shortcut (Windows / Linux) | Shortcut (macOS) | Action |
|---|---|---|
Ctrl + Enter | Cmd + Enter | Send active request |
Ctrl + S | Cmd + S | Save active request to collection |
Ctrl + / | Cmd + / | Open the keyboard shortcuts cheat sheet |
Esc | Esc | Close context menus and dialogs |
What to Read Next
- Request Workbench — Compare live responses against captured traffic with visual diffs.
- Swagger & OpenAPI Studio — Generate interactive API docs and export them to Playground in one click.
- Traffic Inspector — Capture real-world traffic to send into your Playground collections.