10 software tools ranked, each with a short verdict.
Best API testing tools with a free plan: Top 10 Ranked. Katalon ranks first, with a Lister Score of 98.0.
Katalon takes the top spot on this list: it supports parallel test execution on real devices via TestCloud or on-premises runners. Apidog is built for small teams or startups, and enables real-time co-editing so multiple developers can work simultaneously without locking. EchoAPI serves individuals and small teams, and auto-creates API docs and codes using AI.| RANK | ENTRY | BEST FOR | SCORE | FROM |
|---|---|---|---|---|
| 1 |  KatalonUses AI agents to generate test cases from requirements and tickets | All-in-one testing suites | 98.0 | $205/month |
| 2 |  ApidogSyncs mocks, tests, and documentation when the API spec changes | small teams or startups | 92.0 | – |
| 3 |  EchoAPIGenerates test cases for fast and stable API validation | individuals and small teams | 92.0 | – |
| 4 |  InsomniaProvides unlimited projects and collection runs on the free tier | API developers | 92.0 | – |
| 5 |  Telerik.comFeatures integrated AI tools like MCP servers and agentic UI generators | developers building .NET and JavaScript applications | 92.0 | – |
| 6 |  Thunder ClientAllows teams to save collections to Git repositories for collaboration | developers using VS Code or JetBrains | 92.0 | – |
| 7 |  StepCITests REST, GraphQL, gRPC, SOAP and more | engineers | 90.0 | – |
| 8 |  SoapUISupports REST, SOAP, GraphQL, and JMS protocols | individuals and users working on a single machine | 88.0 | – |
| 9 |  FirecampAllows team collaboration in a centralised workspace | teams seeking an all-in-one API client | 86.0 | – |
| 10 |  AlleForgeAllows users to send requests and inspect responses directly in the browser without installing software | modern API development teams | 84.0 | – |
CURATED · UPDATED HOW WE RANK → | ||||
Start from what you need it for. Where each entry fits best:
Each entry's Lister Score on this ranking weighs fit to the list (40%), evidence on the site (20%), published detail (20%) and buying signals (20%).
Each entry's full verdict is below.
Katalon is an end-to-end AI testing platform designed for quality assurance teams. It unifies automation, management, execution and production insights into a single system.
Apidog is an all-in-one API platform for design, debugging, mocking, testing, and documentation. It allows teams to manage the entire API lifecycle within a single workspace.
EchoAPI is an integrated platform offering API debugging, design, automated testing, and documentation generation. It provides development teams with a seamless workflow experience to enhance productivity.
Insomnia is a collaborative API development platform supporting REST, GraphQL, gRPC and more. It offers AI-native design, mocking, testing and debugging capabilities for developers.
Telerik.com offers comprehensive .NET and JavaScript component suites alongside AI tools. It provides a unified package for building modern web, mobile, desktop, and cross-platform applications.
Thunder Client is a lightweight REST API client designed for VS Code and JetBrains. It enables fast, local-first API testing without context switching.
Step CI is an open-source API testing framework. It automates API testing and quality assurance processes.
SoapUI is a product. It says it is built for individuals and users working on a single machine.
Firecamp is a multi-protocol platform offering instant API playgrounds for REST, GraphQL, WebSocket and SocketIO. It provides an end-to-end solution with dedicated environments for testing various protocols.
AlleForge is a browser-native API testing platform that requires no installation. It enables teams to build, test, and ship APIs from a single tab.
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Katalon ranks first on Lister. Katalon is an end-to-end AI testing platform designed for quality assurance teams. It unifies automation, management, execution and production insights into a single system.
1. Katalon; 2. Apidog; 3. EchoAPI; 4. Insomnia; 5. Telerik.com; 6. Thunder Client; 7. StepCI; 8. SoapUI; 9. Firecamp; 10. AlleForge.
No free option is confirmed in the recorded pricing for this ranking. Check each provider's pricing page for current plans and trials.
Katalon says it is built for mixed-skill QA teams seeking unified test management and automation, and Apidog for small teams or startups. EchoAPI says it is built for individuals and small teams, and Insomnia for API developers.
SoapUI states that data driven testing is not available in the open source version, and AlleForge that the product does not yet include mock server functionality, which is listed as coming soon. Those are the limits each product publishes itself, not a full account of any plan.
Katalon98.02
Speedscale96.03
vREST NG96.0RANKINGfull ranking →SOFTWAREVERIFIEDKatalon98.02
Karate DSL96.03Speedscale96.0RANKINGfull ranking →SOFTWAREVERIFIEDKarate DSL96.02Insomnia92.03
BrowserStack90.0RANKINGfull ranking →