Postmate ClientYour APIs. Your Machine. Your Data.

A privacy-first REST, GraphQL, and WebSocket API client built natively into VS Code. No cloud sync, no login, no telemetry — just fast, local API testing that respects your data.

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Import from Postman, OpenAPI & Swagger

Bring your work with you. Import Postman v2.1 collections, OpenAPI 3.0, Swagger 2.0, and cURL commands in one click. Stay productive from minute one — no rebuilding.

Migrate from Postman

GraphQL, Built-In

Send GraphQL queries and mutations with a dedicated Query and Variables editor. Same builder as your REST calls. Variable autocomplete works inside both editors.

GraphQL guide

WebSocket & WSS Testing

Connect to any ws:// or wss:// endpoint, send messages, and watch responses stream in real time. Pick TEXT, JSON, XML, or HTML mode with inline validation. Save WebSocket requests to collections — free, no paid tier.

WebSocket guide

Side-by-Side Response Compare

Diff two API responses with differences highlighted in clean JSONPath notation. Run single comparisons or bulk comparisons across CSV data tables — perfect for staging vs prod regression checks.

See it in action

Data Tables & Per-Request Tagging

Attach a CSV data table to any environment — automatically active across every request. Tag rows with a _dtag column to filter which rows appear per request. Unique to Postmate Client.

Learn about tagging

Tests, Assertions & Scripts

Write tests in plain English with the tabular editor, or use the full pm scripting library. Pre/post-request scripts, built-in test snippets, one-click JSON Schema generator — all without leaving VS Code.

Testing guide

Collections, Environments & Chaining

Organise requests into collections and nested folders. Manage dev, staging, and prod with named environments and {{variables}}. Chain requests visually to pass tokens and IDs between calls.

Learn more

CI/CD Ready

Run collections from the command line, automate API tests in any pipeline, and generate HTML reports for stakeholders. Free CLI — no paid tier required.

CLI reference

Local-First. VS Code Native. Free Forever.

Runs entirely inside VS Code with zero external runtime. Every feature, every collection, every environment — free. No cloud sync, no login, no telemetry, no paid tiers.

Compare plans

5.0 on the VS Code Marketplace

Switching from Postman? Import your collections in one click →

SEE IT IN ACTION

Compare two API responses in seconds

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.

Postmate Client comparing two API responses side-by-side with diff highlights — Postman alternative for VS Code

Single-row compare guide →·Bulk CSV compare guide →

Why developers are switching to Postmate Client

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.

A real request builder, not a text file

Postmate Client gives you a full visual request builder inside VS Code — tabs for params, headers, body, auth, tests, and pre/post-request scripts. Build REST, GraphQL, and WebSocket calls without writing any boilerplate.

Every input field supports dynamic variables out of the box, so you can keep tests realistic without hardcoding data:

Postmate Client UI — privacy-first Postman alternative running inside VS Code with request builder, response panel, and data tables

Combine with environments to switch between dev, staging, and prod without touching the request. Chain requests, write tests, compare responses, stream WebSocket messages, filter test data by tag — all from the same visual editor.

Postmate Client vs Postman vs Thunder Client

	Postmate Client	Postman	Thunder Client
Runs inside VS Code	✅ Native	❌ Separate desktop app	✅ Native
Works offline	✅ Always	⚠️ Limited	⚠️ Limited
Works without login	✅ Always	❌ Required to use	⚠️ For paid features
No cloud sync	✅ Local-only	❌ Cloud default	✅ Local
No telemetry	✅ None	❌ Yes	❌ Yes
GraphQL support	✅ Built-in	✅ Yes	⚠️ Limited
WebSocket / WSS support	✅ Free	⚠️ Yes (login required)	💰 Paid tier only
Import Postman / OpenAPI / Swagger / cURL	✅ Built-in	⚠️ Partial	⚠️ Partial
Pre/post-request scripts	✅ Built-in	✅ Yes	⚠️ Limited
Side-by-side response compare	✅ Built-in	❌ Manual	❌ Not available
Bulk response comparison (CSV-driven)	✅ Built-in	❌ Scripting required	❌ Not available
Data tables linked to environments	✅ Built-in	❌ Not available	❌ Not available
Per-request data tag filtering	✅ Built-in	❌ Not available	❌ Not available
CLI for CI/CD	✅ Free	💰 Paid (Newman / Enterprise)	💰 Paid tier
Price	✅ Free forever	💰 Paid plans	💰 Free + paid plans

Get started in under a minute

Install the Postmate Client extension from the VS Code Marketplace.
Click the Postmate Client icon in the VS Code Activity Bar, then click New Request.
Paste a URL, hit Send — your first API call without leaving the editor.

Read the Getting Started guide → · Or import everything you already have →