Free tools

Free OpenAPI tools for API developers

Browser tools for OpenAPI and Swagger specs, built on the engine Octri uses to generate docs and SDKs. Check a spec in seconds, with no account and nothing to install.

See the tools

Free OpenAPI and Swagger tools

Each tool has its own page. Open one and use it straight away.

Check an OpenAPI or Swagger spec online

Your OpenAPI file drives the reference docs, the SDKs and the tools an agent calls. These free API tools read it the way those generators will.

Most teams find the gaps in a spec after something has been built from it. A generated client returns untyped objects, half the endpoints on the docs site have no description, two methods collide and one gets renamed. An OpenAPI spec checker moves that moment earlier. You run it on the file you already have, read what it found, and fix the document while the change is still a few lines of YAML.

Every tool here runs in the browser on the OpenAPI or Swagger file you already have, in JSON or YAML. There is nothing to install and no CLI to set up, so a spec gets checked from wherever the question comes up, and each tool’s card above says what it takes.

They run on the same engine that generates Octri’s docs and SDKs in ten languages, so what a tool reports is what the code generator would run into. Each one has its own page, which explains what it checks and why it matters for the SDK and the docs built from your spec.

When to check an OpenAPI spec

Four moments when a quick read of the spec saves a slower fix later.

  • Before you publish an SDK

    Catch what is missing from a spec while it is still cheap to fix, before a release freezes it into a public client.

  • When a spec change lands

    Check the branch before it merges, so a new endpoint that arrives half described is caught in review.

  • When the docs feel thin

    An undescribed parameter is the first gap a reader notices on a reference page. Find it in the spec, where one edit fixes every page built from it.

  • When you are choosing an API

    Run a vendor’s public spec through the tools to see how well it describes itself before you build against it.

When the spec is ready

Octri turns the same spec into a docs site, SDKs in ten languages, an MCP server and monitoring, and keeps checking the spec on every change.

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Questions

Yes. No account, no card and no trial that runs out. Each tool limits how often one address can run it, and its own page says how often.