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12 free tools for API design, development, and testing

Your APIs will be up and running quickly and efficiently thanks to these free and free-tier services, as well as open source utilities.

Tools for developing, testing, and managing RESTful APIs have also increased in response to their popularity. There are a variety of services available to assist you in taking your API from concept to production, whether you're an expert racing against an impossible deadline or a novice establishing your first API. Many of them are free of charge.

The list of free API functioning services is provided below. Some are quick-and-dirty programs that will make building or testing an API easier. Others are entry-level tiers for complete, professional-grade API management services, enabling you to start off on a trial basis and upgrade to a higher level of (paid) service as and when you need it.

Amazon API Gateway

The majority of AWS's services, including Amazon API Gateway, are accessible to developers for free through the AWS Free Tier. The one year duration and one million API calls per month cap on your free Amazon API Gateway are plenty to get you started.

You can create front-end APIs for programs created using Amazon EC2, AWS Lambda, or "any web application" using the complete, for-pay version of Amazon API Gateway, which also includes meta-tools like traffic management, API version control, and monitoring.


A visual API designer, support for both REST and SOAP APIs (easing the transition from the latter to the former), a workflow system that enables multiple API calls to be triggered in succession, and dashboarding for everything that needs to go right but could go wrong are all features of the API monitoring and alerting service APImetrics. Although the business does not have a free tier, all of its service tiers are available for a 14-day free trial. The cheapest plan costs $18 a month and allows for 20,000 calls per month, however all call outcomes are saved indefinitely and are not charged separately.


You may create straightforward tests, or assertions, with Assertible to keep an eye on in-use APIs. Swagger, Postman, and curl are a few common third-party formats from which you can import APIs. If you're testing outside of your default domain, you can optionally perform tests with SSL validation and execute them with different environmental conditions (such as staging vs. production). Additionally, Assertible tests can be run automatically or in response to triggers, with test results being reported to GitHub.

Only two online services, ten tests per service, and 1,000 results can be saved under the free personal plan. Higher usage caps and more frequent test execution are available with paid plans, which start at $25 per month.


An API load testing service called BlazeMeter offers real-time reporting. Geo-distributed load testing, which allows traffic to be generated from servers across several continents, and support for tests made with Apache JMeter are additional features. To make your tests more realistic and representative of actual use, mock services and test data can be created and constructed.

You can conduct 10 tests per month with a maximum runtime of 20 minutes each, up to 50 concurrent users, one shared load generator, and one week of data retention when using BlazeMeter's free tier. Paid packages with 1,000 concurrent users, 200 tests annually, and three months of data retention begin at $99 per month.

For testing or debugging front ends that send requests, offers you a variety of HTTP API endpoint responses. You configure the answers via URL parameters rather than through a web interface. This makes automating the use of the service simple.

You can request a web page containing n HTML links, for instance, to test a web scraper, using the /links/:n endpoint. Httpbin, the program that powers the service, is also accessible as a Python package with an MIT-like license, allowing you to host it locally.

IBM API Connect

Similar to AWS, IBM Cloud provides a free tier that is sufficient to give developers a taste of what is offered, but not fully equipped enough to allow them to create full-fledged production apps. Additionally, IBM Cloud, like AWS, provides IBM API Connect as a free API administration solution.

Initially, IBM API Connect was only a tool for building APIs and connecting them to live code. These days, it also comprises instruments for enforcing API policies, promoting discovery, developing composite API designs, and integrating cloud services with corporate information systems. The service offers 50,000 API calls each month in its free tier, which is more than enough to get started. Keep in mind that after thirty days of inactivity, IBM Cloud automatically deletes any free-tier services, so use it or lose it.


Want to use fictitious data to test an API reading system? A number of endpoints provided by JSONPlaceholder provide fictitious data in a few standard formats, such as postings to message boards, comments, photos, to-do lists, and so on. All HTTP methods (GET, POST, PUT, etc.) are supported, and all results are provided as JSON.


How can you be certain that after it goes live, your public-facing API won't collapse and die? only after evaluating how well it withstands a big load. Test results will be given to you in real time via a browser page if you register a target host's endpoint with Loader's web interface or API. With the service's free tier, you can test up to 10,000 simulated customers and two URLs on a single target host for one minute at a time. Most usage caps are lifted with paid plans, which start at $99.95 per month.


For quickly and dirtyly mocking up REST and SOAP endpoints, use Mockable. The lowest tier is free forever and supports HTTPS for mocks, but it only allows you to construct up to 10 mocks per three-person team and deletes any routes that are not used for three months. Additionally, logs are only kept for 24 hours or 5MB. The best part is that you can test it out without even registering. As soon as you access the admin console, temporary accounts are instantly created for you.


You can establish mock endpoints for testing using, an API gateway service run by Kong. Endpoints can log and examine call activity, use any HTTP method, return data in JSON, YAML, XML, or HTML, and attach CORS headers to responses. Mocks can be made to more closely resemble the actual results returned from a live server by using data in HAR format to automatically produce HTTP answers. Additionally, Mockbin is accessible as an open source project with a flexible license.


A web-based toolkit called Runscope is available for checking the functionality, accuracy, and debuggability of your APIs. Along with a variety of other widely used formats, such as the format Runscope uses for its own testing solutions, you can import test plans using the Swagger 2.0 API definition standard. Although there is no free tier, all pricing tiers other than the custom business rate provide 14-day free trials.

Swagger Inspector

Similar to Httpbin, Smartbear's Swagger Inspector allows you to query APIs directly from the browser and saves the results for subsequent analysis. In addition to supporting REST APIs, Swagger Inspector also works with SOAP and GraphQL. Based on the tests you've run, documentation for your API can be automatically created. Paid accounts begin at $75 per month, and the free plan supports three API definitions.

- By Serdar Yegulalp

- Source: InfoWorld


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"Discovering the right tools can transform API design and development. These 12 free resources serve as invaluable icos in the tech landscape, simplifying complex processes. From intuitive design interfaces to rigorous testing platforms, they empower developers, ensuring seamless development journeys. Embracing these tools is akin to having a trusted guide, making the intricate world of APIs accessible to all."

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Very nice article, I think there should be more content like this, because we live in a time when digital technology is becoming more and more integrated into our lives, so we need to know more about it. I am currently studying to become a web designer and I can say that it is a very important profession in the future and very interesting in general. Now, for example, I'm doing a task to create beautiful patterns vector, which is still a bit difficult for me, but it's only now, because not everything can be easy at the first moment. I also want to dive deeper into the IT sphere in the future.

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