Local-first API client + mock server
StubHouse is the desktop API client that takes mocking seriously. Native, offline, file-based — built for the developer who has to ship before the API exists.
Available for macOS, Linux, and Windows.
matcher:
method: GET
path: /users/:id
response:
status: 200
body:
id: "{{params.id}}"
scenarios:
outage: 503
slow: delay 900ms // workspace ready base_url = http://127.0.0.1:4000 env = mock
One workspace for real requests, environments, imports, cURL export, and local mock rules.
Two tools. One binary.
Other API clients bolt on mocks as a paid afterthought or a separate process. StubHouse pairs the daily request workflow with a headless local mock runtime, a desktop server panel, live logs, scenarios, and test-runner hooks.
200 OK · 132 ms
{
"items": [{ "id": "u1", "name": "Ada" }]
}Routes are matched by priority: exact, params, wildcards, then catch-all.
Source of truth
No proprietary database. No cloud account required. A workspace is a `.stubhouse/` directory of YAML files: requests, mock rules, environments, scripts. Commit it to git. Diff it in PRs. Move it between machines with `cp -r`. The tool builds on top of files; the files outlive the tool.
id: req_get_user
name: "Get User by ID"
description: |
Retrieves a single user by their unique ID.
method: GET
url: "{{base_url}}/users/{{user_id}}"
headers:
- key: Authorization
value: "Bearer {{auth_token}}"
enabled: true
auth:
type: bearer
token: "{{auth_token}}"
tags:
- users
- readThe mock server
Mock rules live next to collections, parse in Rust, and are served from the same core used by the desktop app. The current matcher handles methods, exact paths, path params, wildcards, and catch-alls.
matcher:
method: GET
path: /users/:id
response:
status: 200
headers:
content-type: application/json
body:
id: "{{params.id}}"
name: Ada`stubhouse serve` starts the local mock runtime without opening the app. Frontend tests can point at `127.0.0.1` while the backend is still being written.
# Create a workspace, validate it, serve mocks
stubhouse init acme-api
stubhouse validate
stubhouse envs
stubhouse import openapi ./openapi.yaml
stubhouse scenario list
stubhouse serve --port 4000curl http://127.0.0.1:4000/users/usr_1
curl -X POST http://127.0.0.1:4000/users -d '{"name":"Ada"}'
stubhouse export curl collections/users/get-user.yaml --env devThe runtime now covers the parts that make mocks useful during product work: scenarios, logs, hot reload, control APIs, faults, passthrough, recording, and stateful resources.
Available now
Phase 1 is complete: requests, auth composition, environments, interpolation, history, import, cURL export, and the CLI. The mock runtime now builds on top of that same file-based workspace with scenarios, hot reload, live logs, faults, passthrough, recording, resources, and control routes.
HTTP runtime
HTTP/1.1, HTTP/2, TLS, auth composition, and JSON/text/form bodies.
request engine: reqwest + rustls
Environments
Workspace environment files, variable resolution, and inline resolved-URL preview.
url: "{{base_url}}/users/{{user_id}}"Import / export
Postman and OpenAPI 3 import, plus cURL and OpenAPI YAML export.
stubhouse import openapi ./openapi.yaml
Headless mocks
Embedded Hyper mock server with YAML rules, hot reload, request logs, and control routes.
stubhouse serve --port 4000
Route matcher
Exact paths, path params, wildcards, catch-alls, method matching, and script conditions.
GET /users/:id when params.id != ""
Tests
Rhai response assertions with CLI and desktop test runs, including JUnit XML output.
stubhouse test --env ci --junit results.xml
Automation path
The CLI can initialize, validate, inspect environments, import Postman or OpenAPI, export cURL or OpenAPI YAML, serve mocks, switch scenarios, and run Rhai assertions with optional JUnit output.
# Create a workspace, validate it, serve mocks
stubhouse init acme-api
stubhouse validate
stubhouse envs
stubhouse import openapi ./openapi.yaml
stubhouse scenario list
stubhouse serve --port 4000Rhai assertions · shipped
JUnit XML output · shipped
Mock rule conditions · shipped
It's a binary
stubhouse serve and ship.The same mock engine can run from the command line. Spin up local API responses before your app tests, point the frontend at `127.0.0.1`, and keep backend availability out of the loop.
# CI: serve local mocks, then run your app tests
stubhouse serve --port 4000 &
MOCK_PID=$!
npm test
kill $MOCK_PIDHonestly
A direct comparison with the tools you already know. We ship the embedded mock as part of the product, not as an upsell.
StubHouse vs Postman, Insomnia, Bruno, and Yaak
Local-first workspaces, files on disk, native app shell, and the mock server roadmap in one focused table.
Compare with other apps| StubHouse | Postman | Insomnia | Bruno | Yaak | |
|---|---|---|---|---|---|
| Local-first (no account) | ✓ | ✕ | ✓ | ✓ | ✓ |
| Files as source of truth | ✓ | ✕ | ✕ | ✓ | ✓ |
| Embedded mock server | ✓ | ◐ | ✕ | ✕ | ✕ |
| Stateful mocks | ✓ | ✕ | ✕ | ✕ | ✕ |
| Scenario switching | ✓ | ✕ | ✕ | ✕ | ✕ |
| Recording mode | ✓ | ◐ | ✕ | ✕ | ✕ |
| Fault injection | ✓ | ✕ | ✕ | ✕ | ✕ |
| Mock control API | ✓ | ✕ | ✕ | ✕ | ✕ |
| CI / headless mode | ✓ | ✓ | ✕ | ✓ | ✕ |
| OpenAPI schema validation | import/export | ✓ | ✓ | ✕ | ✓ |
| Native binary (no Electron) | ✓ | ✕ | ✕ | ✓ | ✓ |
| Scripting language | Rhai | JS (V8) | JS (V8) | JS (V8) | — |
| Free and open source | ✓ | ✕ | ✓ | ✓ | ✓ |
Sourced from public information as of 2026-05-21. Updated when competitors ship. Corrections welcome — open a PR.
Under the hood
Tauri 2 shell. Rust core. `hyper` HTTP runtime. `rustls` for TLS. Embedded mock server runs in a Tokio task in the same process as the UI. Numbers below stay illustrative until published release artifacts include measured install sizes.
Cold-start bar uses the same discipline — measure before launch, publish with releases.
It's free. It's open.
StubHouse is open source under the MIT License. No usage tracking. No telemetry without an explicit opt-in. No "Pro" features held hostage. The full source — desktop app, CLI, and core libraries — is on GitHub. PRs welcome.
$ git clone https://github.com/stubhouse/stubhouse
$ cd stubhouse && cargo build --release
Finished release [optimized] target(s) in 2m 14sReady when the API isn't
Free, open source, and available for macOS, Linux, and Windows.