OpenAPI / Swagger Viewer
List the endpoints in an OpenAPI (Swagger) JSON document.
Overview
Paste or upload an OpenAPI (Swagger) JSON document and the viewer lists every path, method, and operation summary in a clean table. No fancy UI - just a fast way to skim what an API exposes.
It's for developers who want to inspect an OpenAPI spec without launching Swagger UI or pulling the spec into a heavy editor. Reach for it when evaluating a third-party API, reviewing a teammate's spec PR, or building a quick checklist of endpoints to implement.
How it works
The viewer parses OpenAPI 3.x and Swagger 2.0 documents (both JSON, with YAML as an option). It walks the paths object and lists every operation - HTTP method, path, summary, tags, and any operationId.
Parameters are summarised per path (path/query/header). Response status codes are listed with their descriptions. The viewer doesn't attempt to "try it out" - it's for reading, not request execution.
Examples
- Simple GET:
GET /users getUsers "List all users" - Tagged operations:
POST /pets createPet tags: [pets] GET /pets/{id} getPet tags: [pets] - Path with parameters:
GET /orders/{orderId} Parameters: orderId (path, string, required) Responses: 200 OK, 404 Not Found - Filter by tag in the viewer to focus on one domain area.
FAQ
Does it validate the spec?
It parses with basic syntax checking but isn't a full OpenAPI validator. For deep validation use swagger-cli or the Spectral linter.
Does it support YAML?
Yes - the viewer accepts both JSON and YAML. They're parsed to the same internal model.
Can I use this to make API calls?
No - it's read-only. For executable previews use Swagger UI, Postman, or the OpenAPI Snippet Exporter to convert into cURL/HTTPie commands.
What's the difference between OpenAPI 2.0 and 3.x?
OpenAPI 2.0 was Swagger's last version before the spec was donated to the OpenAPI Initiative; 3.x added components, request body separation from parameters, and richer schema support. New specs should target 3.1.