How to use OpenAPI Viewer
The OpenAPI viewer parses an OpenAPI 3.x or Swagger 2.0 spec — in JSON or YAML — and shows a searchable, colour-coded list of every endpoint. Paste your spec and it lists each path and HTTP method with its summary, plus the API title and version, and a search box filters by path, method, summary, or tag. Everything is parsed in your browser, so internal or unpublished API descriptions never leave your device.
- Paste your OpenAPI or Swagger spec into the input.
- Read the API title, version, and endpoint count.
- Use the filter box to narrow to a path, method, or tag.
- Copy the endpoint list from the result actions if needed.
Your data never leaves your device — 100% private processing.
OpenAPI and Swagger in brief
OpenAPI (formerly Swagger) is the de-facto standard for describing HTTP APIs in a machine-readable document. The spec lists every path, the HTTP methods it supports, the parameters and request bodies they accept, and the responses they return, all under an info block with the API’s title and version. Because the format is standardised, tooling can generate documentation, client libraries, and mock servers from it. This viewer focuses on the most common need — seeing at a glance what endpoints an API exposes — without the weight of a full documentation stack.
| Method | Typical use |
|---|---|
| GET | Read a resource |
| POST | Create a resource |
| PUT / PATCH | Update a resource |
| DELETE | Remove a resource |
Reading a large spec quickly
Real-world specs can list hundreds of endpoints, which is hard to navigate as raw text. Sorting endpoints by path groups related operations together, and colour-coding the method makes it easy to spot the read, write, and delete operations at a glance. The search filter is the fastest way in: type part of a path to jump to a resource, a method to see every write endpoint, or a tag to view a functional area. Because the viewer keeps everything local and instant, it is a lightweight companion for API reviews and exploratory work where spinning up a full documentation server would be overkill.
Worked examples
YAML spec
Inputs: Pet Store YAML
Result: GET/POST /pets, GET/DELETE /pets/{id}
JSON spec
Inputs: Health-check JSON
Result: GET /health
Filter
Inputs: Search "pets"
Result: Only pet-related endpoints
Glossary
- OpenAPI
- A standard, machine-readable format for describing HTTP APIs; formerly called Swagger.
- Endpoint
- A specific path and HTTP method combination that an API exposes.
- Operation
- The description of what a given method on a path does, including its summary and parameters.
- Tag
- A label grouping related operations, often used to organise API documentation.
Related reading
Frequently Asked Questions
Why use OpenAPI Viewer?
- Parses OpenAPI 3.x and Swagger 2.0 in both JSON and YAML
- Lists every endpoint with a colour-coded HTTP method and summary
- Filters endpoints instantly by path, method, summary, or tag
- Runs entirely in your browser so private specs are never uploaded
Common use cases
- Quickly scan an unfamiliar API’s endpoints without a heavy tool
- Review a spec during code review or API design discussions
- Check an internal API description without pasting it into a cloud service
- Find a specific endpoint in a large spec with the search filter
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