Impostor / Docs

Getting started

Install Impostor, open a workspace, and send your first request.

Install

Download the latest build for your platform from impostor.uk/download:

  • macOS — a signed, notarised .dmg. Open it and drag Impostor to Applications.
  • Windows — an NSIS installer (.exe). Run it and follow the prompts.

Impostor is local-first: there’s no account to create and nothing to sign in to.

Open or create a workspace

A workspace is just a folder on disk. Everything you do — requests, folders, environments — is stored as plain files inside it, so a workspace can live in a git repository and be shared like any other code.

On first launch, choose a folder to Open an existing workspace, or Create a new one. The folder’s structure on disk is your collection tree — there’s no separate “collection” wrapper to manage. On the Team plan you can also Clone repository… from the opener to pull a teammate’s shared workspace down from git and open it in one step — see Team sync over git.

You can also open a workspace straight from the OS: right-click a folder and choose Open With ▸ Impostor in Finder (macOS) or Open with Impostor in Explorer’s context menu (Windows). If Impostor is already running, the folder opens in the existing window — and if you have unsaved changes, you’ll be asked before they’re discarded.

Send your first request

  1. In the sidebar, open the Workspace menu (the ⋮ button or right-click) and choose New request.
  2. Set the method (defaults to GET) and enter a URL, e.g. https://httpbin.org/get.
  3. Press ⌘/Ctrl + Enter, or click Send.

The response appears on the right: status, timing, and size up top, with the body pretty-printed and tabs for headers and more. Binary responses are detected and can be saved to a file.

Save it

Press S (or use the menu) to save. The request is written to a <name>.request.yaml file in your workspace folder — the filename is the kebab-case [slug] of the request name, kept in sync whenever you rename. Because it’s plain YAML, you can read, diff, and review it in git.

Try the sample workspace

Want a ready-made workspace to explore? The support repo ships a self-contained example that demonstrates every protocol and feature — HTTP, auth, inheritance, TLS/mTLS, WebSocket/SSE/gRPC/MCP, and scripting — plus the mock backend the requests target.

git clone https://github.com/TheImpostorApp/support.git
cd support/mock-server && docker compose up -d   # start the mock backend

In Impostor, Open folder → select support/mock-workspace, pick the Local environment, and send any request. The workspace uses no machine-specific paths, so it works wherever you clone it.

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