The Ultimate List of Free API Testing Tools for 2025

We all have been there, and we know how hard it is to pick the right tool for your tech or automation setup if you are starting your business in 2026. Choosing among the best free API testing tools and free and open-source API testing frameworks can be overwhelming, especially when you are considering free API testing tools for microservices or free API functional testing tools.

If you’re just starting out, we’re here to make things simple. We’ve listed the top six free API testing tools for developers and testers based on important factors like features, pricing, ease of use, integration with CI/CD pipelines, and reviews.

Before we go into details, here are some of the best free API testing tools for small teams:

When building a product as a startup, speed and quality go together. That’s why choosing the right free API testing tool or free API automation testing tool can make a big difference. The good news? You don’t need a big budget there are many free lightweight API testing tools to help small teams test smarter, faster, and confidently.

But this brings up more questions:

• Which free API testing tools for REST and SOAP are worth your time?

• Do free plans of API testing tools have hidden limits?

• Should your team focus on ease of use, automation, or collaboration features?

• What happens when you use up free credits on free API testing tools with CI/CD integration?

This guide shows the best free API testing tools for startups, free API endpoint testing tools, and free API load testing tools, with comparisons, pros and cons, and a guide to help you pick the right tool for your workflow.

There’s plenty more to explore check out our other posts!

Which Are the Best Free API Testing Tools for Startups?

Here are some popular options for startups and small teams:

1. qAPI (by Qyrus) AI-powered testing that grows with you

qAPI uses AI for API testing without making it complicated. It’s made for teams who want strong features without dealing with complex setup or running out of usage too fast.

Key Features:

• AI test creation: Nova AI bot checks your APIs and automatically creates test cases in seconds.

• End-to-end testing: Runs complete tests without writing a single line of code great for QA engineers and business analysts.

• Virtual users: Free 100–500 virtual users each month, with options to buy more.

• Import options: Supports Postman collections, OpenAPI specs, cURL commands, Insomnia collections, and WSDL files.

• Team collaboration: Up to 3 team members in the free plan with cloud execution.

Pros:

• Setup in 5 minutes with low learning curve

• AI updates tests when APIs change

• Free tier includes 5 AI checks and 10 rows of data testing

• Cloud-based, no need for infrastructure

• Monthly free virtual users increase over time

Pricing (Free Plan): Free for up to 3 collaborators with 5 runs per month

2. Postman Popular tool with tight free limits

Postman is widely used in API testing tools for developers, though the free plan is limited. Still worth using if you already know it.

Key Features:

• Request builder: Easy interface to create and test REST APIs

• Shared workspaces: Work with up to 3 team members

• Integrations: Works with popular CI/CD pipelines and monitoring platforms

• Large community: Many tutorials and support

Pros:

• Popular tool with full documentation

• Large ecosystem with pre-built collections

• Many team members already know it

Pricing (Free Plan): 25 collection runs per month, 5,000 credits monthly

3. Insomnia Simple, developer-friendly testing

Insomnia offers easy API testing tools free with unlimited requests in the free plan a big advantage over Postman’s credit system.

Key Features:

• Clean interface: Simple design developers like

• Unlimited requests: No limits on API calls in the free plan

• Git sync: Built-in version control

• Multi-protocol support: HTTP, GraphQL, gRPC, WebSocket, and more

Pros:

• Unlimited API requests

• Works offline without internet

• Lightweight and faster than heavy GUI tools

Pricing: Free for unlimited collaborators for 1 project; Pro plans start at $12/user/month

4. SoapUI (Open Source) Advanced testing for older systems

If you work with SOAP services or need complex scripting, SoapUI’s free open-source API testing frameworks give advanced features.

Key Features:

• SOAP and REST support: Works with both modern and legacy APIs

• Groovy scripting: Add custom logic and advanced automation

• Complete testing: Functional, security, and load testing

• Enterprise protocols: Can handle complex business APIs

Pros:

• Fully free, no limits or user restrictions

• Strong for complex, enterprise-level testing

• Large community with experience

Pricing: Open-source edition is completely free

5. Bruno Git-native option for developers

Bruno is developer-focused, storing everything as plain text files perfect for teams using Git.

Key Features:

• Git-native: Store collections as plain text for easy version control

• Open-source: No vendor restrictions, customizable

• Offline-first: Works locally

• Fast and lightweight

Pros:

• Fully open-source, no limits or API call caps

• Fits teams using Git

• No vendor restrictions, full data ownership

• Fast-growing community with 32.6k GitHub stars

Pricing: Free and open-source

How to Pick the Right API Testing Tool for Your Team

Consider:

• Ease of use: Can your team start testing quickly?

• Collaboration: Can multiple members share tests easily?

• Integration: Fits your current CI/CD workflow?

• Scalability: Will it work as your team grows?

Features to Look for in a Free API Testing Tool:

• Automated functional testing tools

• Clear reporting

• AI support

• Support for multiple protocols

• Easy integration with CI/CD pipelines

Self-assessment Questions:

• Ease of Use: Can new members contribute without weeks of training?

• Scalability: Will it work as you grow from 3 to 30 developers?

• Collaboration: Can QA, product managers, and developers work together?

• Integration: Works well with CI/CD and existing tools?

• Automation: Supports API automation testing tools, not just manual?

• Support & Community: Can you find help easily?

• Free Tier Limits: Are free plans usable, or will you hit limits too fast?

Want to learn more? Our full collection of posts is ready for you!

Open-Source API Testing Tools

Yes! Tools like SoapUI Open Source and Hoppscotch are free and open-source API testing tools. They are flexible but may need more technical setup and may not be as easy to use as modern SaaS tools like qAPI.

Limits of Free API Testing Tools

Free tools are helpful but may have:

• Fewer advanced features

• Limited team collaboration

• Usage caps

• Less support than paid plans

Our Take

For startups and small teams, the best tool balances simplicity, scalability, and useful free features.

• Postman is good for familiarity but has limits.

• Insomnia is great for developer-focused teams wanting simplicity and unlimited requests.

• Bruno and SoapUI suit open-source API testing framework fans or teams using Git or SOAP.

• qAPI stands out with AI, easy learning, and meaningful free usage.

The right tool helps your team move faster, catch issues early, and grow smoothly. For startups, balancing speed, ease, and cost is key whether you’re considering free API testing tools for mobile backend, free API integration testing tools, or free API mocking tools.