Free toolOpenAPI 3.1No signup

Instant Docs — cURL to OpenAPI & Hosted API Docs

Paste a cURL command, a JSON response, or a HAR file — get an OpenAPI 3.1 spec and rendered API documentation in seconds. Keep pasting; the spec grows.

1

Add requests

Your documentation

Your rendered API docs appear here

Paste a cURL command on the left — endpoints, parameters, schemas and examples are inferred automatically and rendered as a real documentation page.

How it works

1 · Paste traffic

A cURL command from your shell history, a JSON response, or a HAR export from DevTools. Everything is parsed locally in your browser, and secrets are redacted before anything is stored.

2 · Spec grows as you paste

Paths like /users/42 become /users/{userId}, types and formats are inferred from real values, repeated samples refine required fields — and every schema keeps a real example.

3 · Docs & OpenAPI 3.1

A rendered documentation page updates live as you work. Download the OpenAPI 3.1 spec as YAML or JSON any time — free, no account, no watermark.

One converter, any source

Postman to OpenAPI

Open a request in Postman, hit the code icon (</>) and choose Export as cURL. Paste the command here and it becomes an OpenAPI 3.1 operation — repeat per request and your collection turns into a spec.

HAR to OpenAPI

Export a HAR from DevTools (Network → “Export HAR”) and drop it here. HAR entries carry real responses, so every endpoint is documented with request and response schemas in a single import — third-party noise filtered out by origin.

curl -i responses, headers included

Ran curl -i and have the raw HTTP response with status line and headers? Paste it as the response sample — the status code, content type and body schema are all read from it and documented.

JSON to OpenAPI schema

Just have a URL and a JSON response body? Use the URL + JSON tab — types, formats and required fields are inferred from the real values, and every schema keeps a working example.

Frequently asked questions

Does my API traffic get uploaded anywhere?

Parsing and inference run entirely in your browser. Sensitive headers (Authorization, Cookie, API keys) and secret-shaped values (JWTs, sk_live keys, tokens) are redacted client-side first. Only the generated OpenAPI spec — never your raw traffic — is sent to render the live preview.

Which cURL flavours are supported?

Chrome and Firefox “Copy as cURL”, Postman code export, and samples from API docs (Stripe/GitHub style). Multiple commands in one paste, line continuations, single/double/$'…' quoting, -d/--data-raw/--json bodies, -F form data, -u basic auth and -b cookies are all handled.

How do I convert a Postman request to an OpenAPI spec?

In Postman, open the request, click the code icon (</>) and choose “cURL” to export the request as a cURL command. Paste that command here and it becomes an OpenAPI 3.1 operation — repeat for each request in your collection and the spec grows as you paste.

Can I convert a HAR file to OpenAPI?

Yes. Export a HAR file from your browser DevTools (Network tab → “Export HAR”), drop it on this page, and pick which origins are your API. HAR entries include real responses, so you get full request and response schemas in one import. Cookies and tokens are redacted locally before anything is stored.

How do response schemas get documented?

Three ways: paste the response body next to your cURL command (a curl -i response with status line and headers works too), let the tool replay the request from your browser (works for localhost and CORS-permissive APIs), or upload a HAR file — HAR entries include real responses, so you get full request/response docs in one go.

Is the exported OpenAPI spec really free?

Yes — the current version of your spec exports as clean OpenAPI 3.1 YAML or JSON on every tier, with no watermark. Publishing gives you a permanently hosted docs page with a free account.