Digital ToolPad.
Runs in your browserRequests you choose are sent to the destination URL.

OpenAPI & Swagger Viewer

Open an OpenAPI 3.x or Swagger 2.0 file in JSON or YAML and instantly explore endpoints, parameters, schemas, and responses in a clean, interactive UI — 100% private, right in your browser.

Open an OpenAPI or Swagger file

Open a JSON or YAML spec, load one from a URL, or paste it into the source editor. Everything is processed locally.

A Faster, Private OpenAPI & Swagger Viewer

The OpenAPI Viewer turns any OpenAPI 3.x or Swagger 2.0 definition into clean, browsable API documentation. Open a JSON or YAML file and instantly navigate endpoints, parameters, request bodies, responses, and data models — then test calls live, all without sending your spec to a server.

Instant, Lag-Free Rendering

A purpose-built lightweight renderer parses and displays even large specifications in milliseconds — no heavy framework, no endless scrolling, no spinners.

100% Private & Client-Side

Your API definition never leaves your device. Parsing, rendering, and even live requests run entirely in your browser — perfect for internal and unreleased APIs.

OpenAPI 3.x & Swagger 2.0

Full support for Swagger 2.0, OpenAPI 3.0 and 3.1 in both JSON and YAML, including $ref resolution, allOf/oneOf/anyOf, enums, and nested models.

Built-In Try It Out

Send real requests straight from the browser, generate ready-to-run cURL commands, and inspect live responses — documentation and testing in one place.

How to View an OpenAPI File

1

Open your spec

Click “Open File” to load an OpenAPI or Swagger document from your computer, paste it into the source editor, or pull it straight from a URL.

2

Browse the API

Endpoints are grouped by tag in the sidebar with color-coded methods. Filter instantly and click any operation to see parameters, schemas, and responses.

3

Inspect & test

Expand data models, copy a cURL command, or use “Try it out” to send a live request and view the real response — all inside your browser.

Common Use Cases

Backend & API Developers

Sanity-check the OpenAPI output of your framework, verify $ref models resolve correctly, and review responses before publishing your documentation.

Frontend & Integration Teams

Quickly understand a third-party or internal API, find the right endpoints and payload shapes, and test calls without leaving the browser.

Security & QA Reviewers

Audit endpoints, parameters, and schemas of confidential specs locally, with zero risk of leaking an unreleased API to an online service.

Why Choose This Over Other Swagger Viewers?

Built to fix the biggest frustrations developers have with traditional tools.

Stays fast on large specs where heavier viewers stutter or freeze.
Combines readable documentation with live request testing in one screen.
Reads Swagger 2.0, OpenAPI 3.0 and 3.1 — JSON or YAML — with no conversion step.
Runs fully offline in your browser, so confidential APIs never get uploaded.
No account, no ads inside the workspace, no usage limits.
Clean dark-mode UI with instant search across every endpoint and model.

Frequently Asked Questions

Everything you need to know about the OpenAPI & Swagger Viewer.

Is my OpenAPI file uploaded to a server?

No. This OpenAPI viewer is 100% client-side. Your JSON or YAML file is read, parsed, and rendered entirely in your browser using local resources. Nothing is ever uploaded, stored, or logged, which makes it safe for confidential, internal, and unpublished API specifications.

Which OpenAPI and Swagger versions are supported?

The viewer supports Swagger 2.0 as well as OpenAPI 3.0 and 3.1, in both JSON and YAML formats. It resolves internal $ref references and renders composed schemas (allOf, oneOf, anyOf), enums, arrays, and deeply nested models.

Can I test API endpoints directly from the viewer?

Yes. Each endpoint includes a 'Try it out' panel that sends a real request from your browser and shows the live status, timing, and response body. You can also copy a ready-to-run cURL command. Live requests are subject to the target API's CORS policy.

Do I need to install anything or create an account?

No installation and no sign-up. The viewer runs in any modern browser. Just open your OpenAPI or Swagger file — or load one from a URL — and start exploring immediately.

Will it work with large API specifications?

Yes. Unlike some heavier tools that slow down on large documents, this viewer uses an efficient custom renderer and lazy-expands schemas, so it stays fast even for specs with hundreds of endpoints and models.

Browser processing with requests you control

Editing and inspection happen in your browser. When you request a URL, the browser contacts that destination and sends the request details you provide. Browser access rules and the destination server determine which requests are allowed.