I got tired of API testing comparison tables. So I built REST Atlas.

There is something amusing about API testing tool comparisons: the tool publishing the comparison almost always comes out looking like the best choice.

Sometimes the information is accurate. The problem is which information makes it into the table.

Choose the right columns, leave out a few inconvenient capabilities, give your own terminology a dedicated row, and the result becomes fairly predictable.

As someone who builds an API testing tool myself, I understand how this happens. You spend your time solving a particular problem, so naturally you consider that problem important. Your comparison starts reflecting your product’s priorities.

That can help explain a product. It becomes less useful when someone is trying to understand the wider ecosystem.

I wanted a place where I could explore REST API testing tools, apply consistent filters, and compare their documented capabilities using the same fields.

I found directories, GitHub lists, articles, and broader ecosystem maps. Several were useful, but I couldn’t find one that worked the way I wanted.

So I built REST Atlas.

A place to explore the REST API testing ecosystem

REST Atlas is an interactive map and directory of tools that support REST API testing.

You can browse tools by category, search for particular capabilities, filter the directory, and compare tools side by side.

The catalogue covers different parts of the work:

• API clients
• Functional testing
• Test generation
• Contract and schema testing
• Security testing
• Performance testing
• Mocking
• Traffic recording and replay
• Monitoring

A tool can belong to several categories. That matters because the boundaries are rarely clean. An API client might also run automated tests, provide mocks, and execute scheduled checks.

The comparison includes practical information such as licensing, pricing model, interfaces, execution options, test creation, and CI/CD support.

Those details often matter more than another generic “best API testing tools” article. A team that needs local execution and version-controlled test assets has different constraints from a team looking for hosted monitoring.

The aim is to make those differences easier to see.

Consistent criteria, with sources people can check

Calling a comparison “objective” is easy. Keeping the information accurate takes work.

The starting principles for REST Atlas are:

The same comparison fields apply to every tool. Adding another product does not create a special set of columns designed around its strengths.

Entries include sources and a verification date. Readers should be able to check where the information came from and see when it was last reviewed.

Unknown information stays unknown. Missing evidence should not automatically become a red cross. “Not confirmed” and “not supported” mean different things.

Licensing and pricing are separate. A free plan does not make a product open source. A public repository can have restrictions. An open-source core can coexist with paid editions.

The catalogue also needs to describe the scope of each entry carefully. A desktop application, its open-source core, and the vendor’s hosted platform may have different capabilities and terms.

These distinctions make the data harder to maintain, but they make the comparison more useful.

No advertising or sponsored placements

REST Atlas has no advertising, sponsored tool placements, analytics, cookies, or tracking.

You can browse, filter, and compare without creating an account.

For transparency, I am the founder of Rentgen, and the REST Atlas repository lives under the Rentgen-io GitHub organization.

Rentgen is included in the catalogue. The same fields, source requirements, and contribution rules apply to it.

That relationship should be visible to anyone evaluating the project.

The catalogue is open to contributions

I started with tools I know. There will be tools missing, details that need correcting, and capabilities that change after an entry is reviewed.

The repository is public so people can help improve it.

All tool data lives in a single tools.json file. The application reads that file to build the directory, map, filters, and comparisons. Adding a tool does not require changing the application code.

To contribute:

1. Read CONTRIBUTING.md for the supported fields and formats.
2. Add or update an entry in tools.json.
3. Open a pull request with sources supporting the information.

Tool authors are welcome to contribute. So are people who use the tools and notice something missing or inaccurate.

Suggestions for better comparison criteria are welcome too. Consistent fields are useful only if they help people make real decisions.

For now, the scope is deliberately focused on REST API testing. Tools that support several protocols can be included when they also support REST.

I would rather maintain a useful, focused catalogue than keep expanding its scope until the details become impossible to follow.

If you work with REST APIs, try it with a few tools you already know. Check whether the comparison represents them accurately. Add a missing tool, correct an entry, or suggest a field that would help you choose.

Explore: restatlas.org

Repository and contributions: github.com/Rentgen-io/rest-atlas