A privacy-first REST API client built natively into VS Code. No cloud sync, no login, no telemetry — just fast, local API testing that respects your data.
Pick two environments. Hit Compare. Postmate Client fires both calls in parallel, diffs the responses, and shows you only what changed — in clean JSONPath notation. Need to compare hundreds of inputs? Point it at a CSV data table.
Most API clients were built for the cloud era — sync everything, log in everywhere, ship your tokens to someone else's servers. Postmate Client takes the opposite approach. It runs entirely inside VS Code, stores everything locally, and never phones home.
Postmate Client gives you a full visual request builder inside VS Code — tabs for params, headers, body, auth, tests, and pre-request scripts. Build the most complex API call without writing any boilerplate.
Every input field supports dynamic variables out of the box, so you can keep tests realistic without hardcoding data:
Combine with environments to switch between dev, staging, and prod without touching the request. Chain requests, write tests, and compare responses — all from the same visual editor.
| Postmate Client | Postman | Thunder Client | |
|---|---|---|---|
| Runs inside VS Code | ✅ Native | ❌ Separate desktop app | ✅ Native |
| Works offline | ✅ Always (no telemetry calls) | ⚠️ Limited | ⚠️ Sends telemetry |
| Cloud sync required | ✅ Never | ❌ Default | ✅ Never |
| Login required | ✅ Never | ❌ Required to use | ⚠️ For paid features |
| Side-by-side response compare | ✅ Built-in | ❌ Manual | ❌ Not available |
| Bulk response comparison | ✅ Built-in | ❌ Scripting required | ❌ Not available |
| Data-driven testing | ✅ Free | ⚠️ Paid tiers | ⚠️ Paid tier |
| Data tables (per-request) | ✅ Built-in, free | ⚠️ Collection runner only | ⚠️ Collection runner only |
| Data tables linked to environments | ✅ Built-in | ⚠️ Not available | ⚠️ Not available |
| CLI for CI/CD | ✅ Free | ⚠️ Paid (Newman/Enterprise) | ⚠️ Paid tier |
| Telemetry | ✅ None | ❌ Yes | ❌ Yes |
| Price | ✅ Free forever | 💰 Paid plans | 💰 Free + paid plans |
Read the Getting Started guide →
