Multimeter is a Git-native REST client and API testing tool for VS Code. Requests, tests, mocks, and docs are YAML .mmt files in Git — the same files in the visual editor and in CI via testlight. Apache 2.0. No account.

How do I use Multimeter with Cursor, Copilot, or Claude?

Install the VS Code/Cursor extension or add MCP with npx -y mmt-mcp. Agents should call scaffold_test, validate, format, and run instead of guessing .mmt syntax.

Yes. Apache License 2.0. No account required.

Mock Server — Multimeter docs

Open the Multimeter activity bar and choose Mock Server (). This sidebar panel is a lightweight local server for quick prototyping — reflect mode, custom…Markdown (no JavaScript)# Mock server panel Open the **Multimeter** activity bar and choose **Mock Server** ({{btn:server:Mock Server}}). This sidebar panel is a lightweight local server for quick prototyping — reflect mode, custom status codes, and optional loading of a `type: server` file. ![Mock Server sidebar panel — server type, port, status, response, and Run Mock Server](../../screenshots/mock-server-sidebar-panel.png) For full mock definitions in YAML (routing, matching, dynamic responses), use [Mock Server files](./index.md) instead. ## What you can use it for - Frontend/mobile prototyping before the real API is ready - Contract checks while iterating on request/response shapes - Offline development and demos - Point tests or tools at a predictable local endpoint ## Supported protocols | Server type | What it does | |---|---| | **HTTP** | Receive requests on a local port and reply with a simple body/status | | **HTTPS** | Secure HTTP on localhost; optional mTLS — see [TLS below](#https-and-mtls) | | **WebSocket** | Accept connections and echo frames | | **MMT Mock Server** | Load a `type: server` file for full routing — see [Run a server file](#run-a-server-file) | ## Controls | Control | What it does | |---|---| | **Port** | Local port to listen on (e.g. 8081) | | **Reflect** | Echo back what the client sends (HTTP body includes method, path, headers, and body; WS frames echo to the same client) | | **Status** | Optional HTTP response status (e.g. 200, 400, 500) when Reflect is off | | **Content type** | Response body format: json, xml, xmle, text, or urlencoded | Tip: Reflect is a great way to validate what your client actually sends — no backend needed. ## Point your client or tests - In an API `.mmt`, set the base URL to the mock server: `url: http://localhost:8081` - Or use an environment variable and swap presets between real and mock: - `variables.api_url: http://localhost:8081` - Tests and APIs reference it via `<<e:api_url>>` When Reflect is on, the response body includes the payload you sent. Turn Reflect off and set a Status to simulate error paths. ## Request history The panel records each incoming request. Inspect method, URL, headers, body, and arrival order in the history view. See also: [History](../../panels/history.md). ## Run a server file 1. Set **Server Type** to **MMT Mock Server** 2. Click the folder button and select your `.mmt` server file 3. Optionally adjust the port (overrides the file default) 4. Click **Run Mock Server** The server starts with full routing — requests match your endpoints and responses use Multimeter dynamic tokens. See [Edit Mock](./edit.md) and [Endpoints](./endpoints.md). From a `type: server` editor, **More → Run in mock server panel** does the same: focuses this panel, selects the file, and starts. That path does not dirty the editor tab, so you can close the file while the mock keeps running. The status-bar badge then offers **Open mock server panel** or **Open file** — see [Panels — Status bar](../../panels/index.md#status-bar). ## HTTPS and mTLS The panel can run HTTPS on localhost (`127.0.0.1`). - Set **Server Type** to **HTTPS** - Optionally select a **server certificate** (PEM/CRT) and **server key** (PEM/KEY) For mTLS (client certificate verification): - Enable **Require client certificate (mTLS)** - Select a **Client CA** file (PEM) that signed the client certificates you accept When mTLS is enabled, clients without a valid certificate signed by the configured CA are rejected. **TLS only:** ```sh curl --cacert certs-test/ca.crt https://127.0.0.1:8080/ ``` **mTLS:** ```sh curl --cacert certs-test/ca.crt \ --cert certs-test/client.crt \ --key certs-test/client.key \ https://127.0.0.1:8080/ ``` Certificate paths are stored in VS Code workspace state. Only PEM format is supported (`.pem`, `.crt`, `.cer`, `.key`). For TLS in `type: server` files (paths relative to the file), see [TLS](./tls.md). ## Notes and limits - Designed for local development — do not expose publicly - State is not persisted between runs - Response shaping is basic; for complex mocking, use [server files](./index.md) --- See also: [Mock Server overview](./index.md) · [Quick start](./quick-start.md) · [CLI](./cli.md) · [Panels](../../panels/index.md) For AI agents · llms.txt · Home