Compare — Second Spec

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Load a sample spec to compare.

API Docster

Paste an OpenAPI or Swagger spec to generate interactive API documentation with live endpoint testing.

Paste

URL

Sample

Load a sample Petstore spec to try it out.

What is an OpenAPI / Swagger spec?

An OpenAPI document (formerly Swagger) is a machine-readable JSON or YAML file that describes every endpoint of a REST API: the path, HTTP method, request parameters, request body schema, authentication requirements, and possible response codes. The most common versions are OpenAPI 3.0, OpenAPI 3.1 (which aligns with JSON Schema 2020-12), and the older Swagger 2.0. Paste any of them here and the tool will render the full API reference with parameter tables, request body examples, and response schemas.

How to read the output

Each endpoint is grouped under its tag in the left sidebar. The method badge is colour-coded using a familiar code-host palette: GET, POST, PUT, PATCH, DELETE. Click Try It on any endpoint to send a real request from your browser — the response, headers, and status code appear inline. All "Try It" requests go directly from your browser to the API; they do not pass through any server.

Supported spec sources

Paste the spec JSON or YAML directly into the textarea. Fetch from URL if your team hosts the spec (e.g. https://api.example.com/openapi.json) — the tool will GET it and parse it. Sample loads a small demo spec (Petstore) so you can see the output before you bring your own. Specs can be saved to this browser (up to 10) and are auto-named from info.title.

Compare two API specs

Click the Compare button in the top bar to load a second spec. The page splits into two side-by-side panels so you can spot breaking changes, missing endpoints, and parameter drift between two versions of the same API. Useful for reviewing a v1 → v2 migration or auditing the diff between staging and production docs.

Markdown export

The Export MD button downloads a clean, well-formatted Markdown reference for the loaded spec — every endpoint, parameter, request body, and response code, organised by tag. Drop it into your team wiki, a code-hosting repository, or Notion page. The export respects the spec's own descriptions and example values.

Privacy

The tool runs entirely in your browser. No spec, no request, no response, and no response body is ever uploaded to a server. Saved specs live in your browser's localStorage. The page loads no third-party scripts, no analytics, no ad networks, and no fonts from a CDN. For full details, see the privacy policy.

Need a cron job to call that endpoint?

Try Cron Builder — visual cron expression editor with next-run dates, timezone support, and export to systemd / AWS / GCP / Kubernetes. Free, no signup.

Working with bearer tokens?

Try JWT Lens — paste a JSON Web Token to see the header and payload decoded, check expiry, and verify HS256 / RS256 / ES256 / PS256 signatures in-browser. Free, no signup.

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