Introduction
A fast, local, cross-platform API client — a lightweight alternative to Postman.
Impostor is a fast, local API client for macOS and Windows. It does what you reach for Postman to do — build and send HTTP requests, organise them, script around them, talk WebSocket/SSE/gRPC — but it is built to be small and quick, with native performance instead of a heavyweight Electron runtime.
Why Impostor
- Native and fast. A Rust core with an OS-native webview (Tauri), not Electron. Cold start and memory footprint are a fraction of the usual API clients.
- Local-first. Your workspace is just a folder of human-readable YAML files — one request per file. No account, no cloud, no telemetry. Commit it to git and diff/review/branch your API collection like any other code.
- Secrets stay safe. Sensitive values live in your OS keychain, never on disk in plain text.
- Beyond REST. WebSocket, Server-Sent Events, and gRPC are first-class request types, not bolted-on extras.
How the docs are organised
- Getting started — install Impostor and send your first request.
- Building requests — the request editor, environments & variables, scripting, and authentication.
- Protocols — WebSocket, SSE, and gRPC.
- Workflows — the collection runner, importing from Postman/cURL, code generation, and cookies.
- Reference — TLS & certificates, the workspace storage format, and keyboard shortcuts.
New here?
Head to Getting started to install the app, open a workspace, and send your first request.