API Documentation Generator
Create a clean API reference in seconds. Paste an OpenAPI 3 or Swagger 2 document in JSON or YAML, or list your endpoints in a simple form, and get documentation with parameter tables, request and response examples and ready-to-run cURL commands.
- Runs in your browser
- No sign-up
- Free to use
How to use API Documentation Generator
- Paste or open your OpenAPI or Swagger file, or switch to Build manually and describe each endpoint.
- Choose whether to include a table of contents and cURL examples.
- Check the rendered result in the Preview tab or the source in the Markdown tab.
- Copy the Markdown, download it as a .md file, or download a standalone HTML page.
API Documentation Generator features
OpenAPI 3 and Swagger 2
Reads both generations of the specification, in JSON or YAML, and follows $ref references inside the document.
Generated examples
When a schema has no example, a realistic one is built from its types, formats, defaults and enums.
Parameter and field tables
Path, query and header parameters and the fields of request bodies, with type, required flag and description.
cURL for every endpoint
A copy-and-paste command with the base URL, authentication header and JSON body filled in.
Manual builder
No specification yet? Enter methods, paths, parameters and example payloads in a form.
Private by design
The document is processed in your browser. Nothing is uploaded, so internal APIs stay internal.
When to use API Documentation Generator
- Adding an API reference to a README or a wiki that renders Markdown.
- Sending a client or partner a single HTML file that describes your endpoints.
- Reviewing what an OpenAPI file really says before publishing it.
- Documenting a small internal API that has no specification yet.
API Documentation Generator FAQ
Which specification versions are supported?
OpenAPI 3.0 and 3.1 and Swagger 2.0, written in JSON or YAML. The format is detected automatically. References that point to other files or URLs are not fetched; bundle the specification into one file first if it is split.
Where do the example requests and responses come from?
If the specification contains an example, that example is used. Otherwise one is generated from the schema: defaults and enum values where they exist, otherwise a placeholder that matches the type and format, such as a date for a date-time string.
Is my API specification uploaded?
No. Parsing and rendering happen in your browser, and the page makes no request containing your document. That makes the tool safe to use with unreleased or internal APIs.
Can I edit the result?
Yes. The output is ordinary Markdown: copy it into your editor and adjust wording, order or examples. If you regenerate from an updated specification, your manual edits need to be applied again, so it is best to improve descriptions in the specification itself.
How are endpoints grouped?
By their first tag, in the order tags are declared in the specification. Operations without a tag are collected under General. In manual mode all endpoints appear under one Endpoints heading.
What does the manual parameter format look like?
One parameter per line, with fields separated by a vertical bar: name | in | type | required | description. For example: id | path | integer | required | The user id. Only the name is mandatory; the location defaults to query and the type to string.
What good API documentation contains
A developer opening your documentation wants to make one successful request as quickly as possible. That takes four pieces of information: where the API lives, how to authenticate, which endpoints exist, and what a request and its response look like. The generated document follows that order. It starts with the base URL and authentication, lists every endpoint in a table of contents, and then gives each one its own section.
Within a section, the layout is deliberately repetitive. A heading with the method and path, a one-line summary, a table of parameters, the request body with its fields, the possible responses with their status codes, and an example command. Repetition is a feature here: once a reader has understood one endpoint, every other one can be scanned in seconds.
An OpenAPI document is the best source for this, because it is also what tools use to generate clients, mock servers and tests. Keeping descriptions and examples in the specification means every one of those outputs improves together. If you maintain the specification by hand, a few habits pay off quickly: give each operation a summary, mark required fields, add an example to every schema property, and describe error responses as carefully as successful ones.
Markdown is a practical output format because it is readable as plain text and renders almost everywhere: Git hosting services, wikis, static site generators and note-taking tools. The HTML export is for the cases where a single self-contained file is easier, such as an email attachment or a page on an intranet.