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.

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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.

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 response schemas get documented?

Three ways: paste the response body next to your cURL command, 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.