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.

Overview — Multimeter docs

Multimeter projects are folders of YAML .mmt files. The top-level type field decides how a file behaves. Most runs share Environment variables (<<e:>>…Markdown (no JavaScript)# MMT Files Multimeter projects are folders of YAML `.mmt` files. The top-level `type` field decides how a file behaves. Most runs share [Environment](./files/env/index.md) variables (`<<e:>>` tokens) and can produce [Report](./files/report/index.md) output after completion. ## File types | | Type | Purpose | Guide | |---|---|---|---| | $(symbol-method) | `api` | Single HTTP / WebSocket / GraphQL / gRPC request | [API](./files/api/index.md) | | $(beaker) | `test` | Executable flow with steps and assertions | [Test](./files/test/index.md) | | $(server-environment) | `env` | Variables, presets, certificates | [Environment](./files/env/index.md) | | $(layers) | `suite` | Group and run tests or other suites | [Suite](./files/suite/index.md) | | $(book) | `doc` | Generate API documentation | [Doc](./files/doc/index.md) | | $(server) | `server` | Mock server endpoints | [Mock Server](./files/server/index.md) | | $(law) | `judge` | AI judge resource (BYO model / Ollama) | [Judge](./files/judge/index.md) | | $(dashboard) | `loadtest` | Concurrency / ramp-up load scenario (beta) | [Load Test](./files/loadtest/index.md) | | $(file-text) | `report` | Structured results (usually generated) | [Report](./files/report/index.md) | ## Shared metadata Most authored file types share the same documentation fields: | Field | Purpose | |---|---| | `title` | Display name in the UI, docs, and reports | | `description` | Longer explanation (Markdown supported on APIs) | | `tags` | Labels for search and filtering | They appear on **API**, **Test**, **Suite**, **Load Test**, and **Mock Server** files. On **API** and **Test** files, `description` can also document inputs/outputs with `<<i:>>` / `<<o:>>` annotations (allowed values, ranges, Doc tables, Inputs ⋯ picker) — see [Input and output documentation](./files/input-output-docs.md). **Doc** files use `title` and `description` (no `tags`). **Environment** and **Report** files do not use this trio. ```yaml type: api # or test | suite | loadtest | server title: Login description: Authenticate and return a token tags: - smoke - auth ``` ## YAML and UI Every `.mmt` file opens as a **split editor**: - **Left** — YAML. This is the file on disk. Commit it, review it in pull requests, and run it from the CLI. - **Right** — a UI for that file type: API tester, test runner, environment editor, and so on. ![YAML on the left and API tester UI on the right](./screenshots/yaml-ui-split.png) The **YAML** on the left is the file. The **Edit** page on the right writes to that YAML. The normal tester / runner UI is **temporary**: Send and Run use it, but it is not in the file until you **Save to YAML**. Click {{btn:edit:Edit}} on the right to switch that pane into **edit mode** (forms and tabs instead of the run / preview view). Use the back control on the edit header to return. You can always edit the YAML directly. If the tester already has unsaved UI edits, you are asked whether to discard them — see [API](./files/api/index.md#unsaved-changes). If the YAML has errors, the right pane keeps the last valid UI and shows a red {{btn:error:YAML ERROR}} button (same layout as unsaved changes). Open it to read the error, click a line to jump there, or **Restore YAML** to revert to the last valid version. ### Show YAML, UI, or both The editor title bar (top right of the `.mmt` tab) has three layout buttons: | Control | What it does | |---|---| | {{btn:layout-sidebar-left:Hide YAML}} | Show only the UI pane | | {{btn:layout-centered:Show both}} | Show YAML and UI side by side | | {{btn:layout-sidebar-right:Hide UI}} | Show only the YAML pane | The default is both at 50%/50%. Change that with `multimeter.editor.yamlPaneSize` (percentage splits, `Only YAML`, `Only UI`, or fixed YAML widths). To open the file in the default text editor, use the **MMT Editor** dropdown on the tab, **Open With...**, or **MMT: Open as Text** from the Command Palette. ## Next steps - [Getting Started](./quick-start.md) - [Start with a task](./tasks/index.md) - [Browse examples](/docs/examples) For AI agents · llms.txt · Home