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Developer tool
Paste an OpenAPI or Swagger JSON spec to view its title, version, endpoints, and HTTP methods. Free online OpenAPI viewer that runs in your browser
OpenAPI Viewer on ToolBesty is a free online OpenAPI viewer that turns a pasted OpenAPI or Swagger JSON document into a readable outline. It shows the API title and version, then lists every path with the HTTP methods it supports, such as GET, POST, PUT, and DELETE. The spec is parsed live as you type, right in your browser, so you get a quick OpenAPI doc viewer without installing Swagger UI or uploading your contract.
Raw OpenAPI JSON is hard to scan: a single spec can nest dozens of endpoints several levels deep. This OpenAPI visualizer flattens that structure into a simple list of routes and their methods, so you can see the shape of an API at a glance, spot a missing endpoint, or confirm that a path such as /users/{id} exposes the operations you expect.
The viewer reads the standard info and paths objects, which OpenAPI 3.x and Swagger 2.0 JSON files both use. If the JSON is invalid, the parser error appears under the editor so you can fix a stray comma or bracket before looking again. The tool accepts JSON only; convert a YAML spec to JSON first, for example with a YAML to JSON converter.
It is deliberately lightweight. It does not render request or response schemas, generate code, or send test calls. Use it as a quick OpenAPI online outline during code review, API design, or when you receive a spec file and want to know what it covers before loading it into a full toolchain.
ToolBesty is operated by Vishvajeet Shukla. For privacy details on browser tools, accounts, and AI features, read our Privacy Policy.
Replace the sample in the editor with your OpenAPI 3.x or Swagger 2.0 JSON document.
The API title and version appear first, followed by each path and its HTTP methods, updated as you edit.
If a JSON error message appears, correct the spec, then scan the path list to check coverage.
Check which endpoints and methods a pull request adds or removes without reading hundreds of lines of JSON.
Get a fast inventory of routes from a partner's or vendor's OpenAPI file before you start integrating.
Confirm that a framework-generated openapi.json actually exposes the paths and methods you registered.
Tip: after you finish, check Related tools at the bottom of this page for the next step in your workflow.
Quick answers about tools, privacy, limits, and pricing.
It shows the API title and version from the info object, then every entry in paths with its methods listed in uppercase. It does not render schemas, parameters, or example responses.
Yes, as long as the document is JSON. Both formats use the same info and paths structure that the viewer reads.
No. The viewer parses JSON only. Convert your YAML spec to JSON first, then paste the result.
No. Parsing happens in your browser, so internal or unpublished API contracts stay on your device.
The pasted text is not valid JSON. The message from the parser points to the problem, which is often a trailing comma, a missing quote, or an unclosed bracket.
Yes. OpenAPI Viewer is free to use on ToolBesty. Guests and free accounts may have daily limits on some tools; premium tiers can raise or remove those limits. AI tools may also spend credits.
For browser-based tools, processing runs on your device when possible and files are not uploaded for conversion. Optional accounts, usage limits, and AI features are described in our Privacy Policy.
No for most tools — you can start as a guest. An account helps keep higher daily limits and saved work (for example AI resumes).
Close other heavy tabs, use a smaller input file, and try Chrome or Edge on desktop. Very large files can stress browser memory.
Yes, the page is responsive. Complex media or large PDFs still work better on desktop because of memory and CPU limits on phones.
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