The local-first, AI-native OpenAPI studio
Give Codex, Claude Code and Cursor clear API definitions to code against. Generate docs from code and orchestrate tests with AI in the local-first Powerduck desktop app. Host OpenAPI docs and MCP servers for free on Hub.
/orders
post createOrder
get listOrders
/products
get listProducts
/customers
get listCustomerspowerduck.read_spec()
12 operations found
powerduck.start_mock("POST /orders")
Mock server live on :4010
powerduck.generate_tests("POST /orders")
orders.test.js written
powerduck.call_api("POST /orders", {total:49})
200 OK · verified against contract
powerduck.publish_docs()
Reference docs updated
Sign in with Google or GitHub. Powerduck provides built-in AI models and a shared account allowance.
Spec Editor · API Debug · Test · Mock · API Docs · MCP Server
POWERDUCK HUB
Keep your API workflow in the desktop app. Use Hub to share documentation and connect AI tools to your API.
Design, debug and test your API in Powerduck.
Turn your specification into hosted documentation and an MCP endpoint.
Share the docs link, connect an MCP client, and choose whether to list your project publicly.
Free hosting within plan limits. Your business API continues to run on your own backend.
Why Powerduck
A single OpenAPI YAML in your repo drives design, debugging, tests, mocks, docs and MCP — and your coding agents use that same file.
Design, debug, test, mock, document and expose MCP from the same OpenAPI spec, so nothing drifts apart.
Each response is checked against the OpenAPI spec — not just displayed — so a wrong type or path is caught on the spot.
Use Google or GitHub to sign in. Review code, assess tests and inspect changes with built-in AI, while you decide which files to create or publish.
{
"id": "usr_8Kd2Xa",
"email": "ada@example.com",
"created": 1757030400,
"profile": {
"name": "Ada L.",
"locale": "en-GB"
},
"scope": "users:read orders:read"
}
scope is present in the response but is not
declared on components/schemas/User. Add the
property to the schema or remove it from the handler.
Every operation with an operationId becomes a tool. Arguments come from parameters and requestBody. Nothing is hand-written.
Exchange credentials for a bearer token.
Retrieve a single user by identifier.
Create an order for the authenticated customer.
Refund an order in full or in part.
GET /v1/users/{id}
Returns the user object for a valid identifier. If the user has been deleted, an Error object is returned with status 404.
usr_.
SEE IT IN A WORKFLOW
Sign in with Google or GitHub. Powerduck provides built-in AI models and a shared account allowance.
Sign in to open your local workspace. Keep your project files on your machine; selected context is sent to Powerduck’s managed AI when you request analysis.
Sign in with Google or GitHub. Powerduck provides built-in AI models and a shared account allowance.
A reviewable API definition + a local docs link.
Implementation guided by the contract, checked against real responses.
Step-by-step results and failed assertions, not just a generated test script.
Manual control when you need to inspect exactly what happened.
A diagnosis grounded in request results, with changes you can review.
Hosted documentation and an MCP URL, without running your own hosting stack.
START ON YOUR MACHINE
Sign in with Google or GitHub. Powerduck provides built-in AI models and a shared account allowance.
Sign in with Google or GitHub. Powerduck provides built-in AI models and a shared account allowance.
macOS 12+ · Windows 10+ · Linux
Sign in to use the browser workspace. Use the desktop app for local project scans, test generation and iteration history.
Contract verification
Ordinary API clients send the request and show the response. Powerduck also checks every response against the OpenAPI contract, so drift from the spec is caught the moment it happens.
See a working exampletotal:
type: number{
"total": "49.00"
}{
"total": 49
}OpenAPI spec editor
The outline follows the specification's real structure, not a guess based on indentation. Navigate paths and components as a tree, and fix errors where they live.
{
"id": "usr_8Kd2Xa",
"email": "ada@example.com",
"scope": "users:read"
}
API debugging
A request builder shaped like the tools developers already use, plus one thing those tools cannot do by default: verify responses against the contract.
MCP server generator
Your specification is already a tool manifest. Powerduck compiles it into a runnable MCP server and shows exactly which OpenAPI fields produced each tool.
curl /users/{id}
{
"id": "usr_...",
"email": "ada@..."
}
API documentation generator
Reference documentation generated directly from your OpenAPI model, exported as static files and hosted wherever you want.
One source of truth
Open your OpenAPI files locally and work with your API contract, code quality findings, tests and iteration changes in one AI workspace. Built-in models provide evidence-backed review, and repair prompts connect the results to your coding agent.
The file stays in your repository.
Edit, navigate and validate the real contract.
Send requests generated from the same operations.
Compile operations into agent-ready tools.
Publish documentation from the same source.
It is the local-native, AI-driven workspace built around the OpenAPI file itself.
Your project remains local. AI requests send selected source context to Powerduck’s managed model providers. Publishing documentation is a separate action you choose.
Privacy PolicySign in with Google or GitHub. Free includes 300,000 credits daily. Pro is $39/month with 18 million credits every 7 days; Max is $99/month with 60 million. Built-in AI powers Chat, code review and test planning.
Design, debug and test APIs through chat, using local OpenAPI files.
Sign in to use Publish onlineShare hosted API documentation and MCP services with your team and AI agents.
Free tier · monthly or annual plans One account allowanceSubscriptions · free credits reset daily; paid credits reset every 7 days.
Credits included with your planManage your subscription and shared AI credits from your account. Sign in to your console →
FAQ
The practical details around local files, OpenAPI versions, MCP generation and licensing.
Your project remains local. AI requests send selected source context to Powerduck’s managed model providers. Publishing documentation is a separate action you choose.
OpenAPI 3.0, 3.1 and 3.2. Powerduck detects the declared version and validates against the appropriate dialect instead of using a lowest common denominator.
Operations with an operationId become MCP tools. Arguments are derived from parameters and requestBody schemas. Component schemas can be exposed as resources. The generated server updates whenever the specification changes.
Powerduck uses monthly subscriptions. Free credits reset daily; paid credits reset every seven days.
Yes. Existing collections and environments can continue to be used. Powerduck treats the OpenAPI specification as the authoritative contract and helps identify where requests drift from it.
Yes. The same validation and generation engine is exposed through @powerduck/openapi-cli, a CI-ready command-line tool that runs during pull requests and automated pipelines. It supports batch testing across 6 protocols (HTTP, SSE, WebSocket, gRPC, MCP, GraphQL), configurable concurrency, and JUnit-compatible reports for CI integration.