API design and development

6 Tools for API design, development and testing

Oct 25, 2019

Restful API design best practices starts with using the right tools. Api design tools

With today’s businesses running a plethora of systems across diverse environments, taking advantage of the modern IT economy lies in an organisations ability to create value via their APIs and microservices.   While the process of building and managing APIs can be simple at its root (particularly with REST, which is extremely lightweight) there are many hidden complications during implementation. For this reason, we have put together this quick guide to the bests tools for API development to make your tasks easier. 

Building and publishing an API


Linx API design

Linx is particularly powerful for creating or calling internal and external REST web services. It is on the fastest ways to extend an API that requires integration with other technologies. (e.g. you need to load or push data into a database, conjure up a rapport, push updates to notification steam. Or modify or encrypt data at any point, etc).

But it’s just not one of the many REST API development tools in the market, Linx offers several other features from database to cryptography and cloud. So this creates tons of possibilities for integrating your API with multiple different technologies.

Designed for versatility and speed, it uses common programming logic and principles with pre-built functionality to replace large pieces of code. Particularly, for API design. Its features include allowing the assembly and publishing of both REST and SOAP web service endpoints and the choice between implementing your API from scratch – via a wizard. Or simply importing an OpenAPI definition.

Good For (Best Use Case)
Creating and consuming APIs can be a time-consuming process. While configuring APIs are relatively easy for developers, they typically need some custom programming. With Linx, you simply drag and drop a module into your designer canvas and set up some configuration. Time saved.

If you are working with an application which requires consuming several APIs, the process of integration with external services becomes far more efficient. Furthermore, it can be handled by Business Analysts or IT pros alike with relative ease.

There are very few drawbacks to using Linx for your development processes. Whether you have existing applications that you would like to connect via SOAP or REST, or if you wish to build an entire software suite within Linx, the API functionality will work extremely well for making the connections today to enable your applications to “play well with others.”


Linx, however, is not a full API design tool in itself; testing, for instance, should be handled by a third-party application, likewise API documentation.

Self-hosted Designer IDE: Free
Cloud services from $149/month with a developer’s license (1 application)

URL https://linx.software

MORE: The ultimate guide to building your first REST API in low code.



Swagger Editor

swagger editor

Swagger editor is the leading API design tool on the market. It allows you to design and document APIs using a free web-based open-source editor. Also it is designed solely for creating OpenAPI-based APIs. It provides options to work web-based or in a local environment.

Good For (Best Use Case)

Well-documented APIs are a necessary aspect of providing them. Creating documentation can be painstaking, however, if people can’t understand how to use your application’s APIs, they simply won’t use them. It’s very helpful for creating easily shareable documentation that can drastically improve the user experience for those attempting to use your APIs.


It provides instant visualization of the documentation as it is being created, and also has a number of customization options. Then it has some helpful auto-completion tools, and will help create server stubs for APIs in a wide array of programming languages. It does not, however, support hypermedia.


Free – both for download and in the cloud for individuals. Options available for Teams and Enterprises

URL https://editor.swagger.io/

API Testing



Fiddler is a free web debugging proxy that can be very helpful for testing the security of your APIs. It boasts many features, including the ability to log any and all HTTP(S) traffic running between your machines and the internet, and will assist in decrypting any traffic to identify if there are any security holes in your applications.

To test your APIS, only requires one to drag and drop any active session into a menu, and run a set of validations against it, either in plain text or using regex.

Good For (Best Use Case)
Fiddler is an excellent tool for debugging APIs. Also, when working with APIs, particularly if there are sensitive issues surrounding the security of your applications, Fiddler makes an excellent tool for monitoring all HTTPS traffic surrounding the call. It can help detect if there are any attempts at interference, and you can monitor your own tests if you are performing any penetration testing.

With each API call, simply by placing a debugger on it, you can view the full header and payload. Data can be viewed in a range of formats, from XML, JSON, or raw. The interface is a little confusing at first, particularly on a Mac. It currently does not support mobile testing.

The software is free for download. Enterprise pricing with unlimited priority support: $999/user annually.

URL https://www.telerik.com/fiddler



API design best practices don’t come much better than Postman – a complete API development testing and environment which can enable creating simple to complex APIs and to verify their functionality prior to building into your applications. You can manually create simple API calls using a straightforward user-friendly interface.

Good For (Best Use Case)
As ensuring APIs work properly is its own issue, beyond any coding you may need to do, it can be extremely helpful to have an environment where one can verify if payloads are being sent and/or received properly prior to any development work.

Postman provides full integration with existing SDLC methods, ranging from various Agile and Dev/Ops environments to larger waterfall-type organizational models. This makes it well-suited for the professional development process. For this reason, it is regularly used by many software development teams. It is a little memory-intensive, so may run slowly on some computers.

Individuals and Small Teams: Free Enterprise: $18/user monthly (includes advanced features).

URL https://www.getpostman.com


swagger ui

SwaggerUI is an open-source API tool generated using OpenAPI resources. It allows users to view APIs at a high level through a web interface. It provides basic documentation of the resources within the API and enables developers to be able to execute API requests and monitor them so as to determine whether or not payloads are accurately sent, and what results are received.

Good For (Best Use Case)
It is a very useful tool for testing tools during the development process by both developers and testers. SwaggerUI can also be used by end-users looking to evaluate APIs of an application to help understand:
a) how they work, and
b) whether they meet the needs required by their operations.

The strongest point of Swagger is its easy interface – it does not require any specialized knowledge beyond understanding what APIs are. By using a web interface, this makes it lightweight; there’s no need for a download (though this option is available).

There are no dependencies, meaning that it is extremely flexible. Where it is strong in usability, it lacks in complexity. For instance, it does not support Hypermedia, meaning that it may have some problems evolving as new technologies develop.

SwaggerUI is free and open-source

SOAP and REST Testing


SoapUI is a complete API automation testing framework for both REST and SOAP methodologies. Features include API functional testing, performance testing, security, and API mocking, and contains reporting tools for viewing metrics of large-scale API testing procedures. SoapUI has a free open source and professional versions.

Good For (Best Use Case)
SoapUI is ideal for developers who need to build APIs on a daily basis, and those who are required to manage large sets of connections. It provides the ability to monitor the activity and behaviour of large arrays of APIs with high levels of activity.

SoapUI boasts a wide range of functional testing features as well as many important security features, ranging to alerts from SQL injection to XSS and more. It provides an array of highly useful actionable alerts for any problems that may occur.

As it is open-source, developers may modify any of the source code to meet their own needs at any time. It is an advanced tool, so for many users, some pieces may be more complicated than they may be used to. The free trial version does not offer as many of the more user-friendly pieces.

Standard 1-year license: $659. Open Source training and certification: $99

URL https://www.soapui.org/

 BONUS: API Integration


API2Cart provides a unified API that enables connection with various shopping platforms and marketplaces just via one integration. It supports the integration with Magneto, Shopify, WooCommerce, Amazon, eBay, etc. API2Cart has 100+ API methods that allow software providers to manage, add, delete, and sync the data retrieved from e-retailers’ stores. 

Good For (Best Use Case)
It is a very useful service for software providers who need access to e-stores’ data related to orders, products, customers, etc. and want to avoid the development and support of connection with each shopping platform separately. 

API2Cart supports the integration with multiple popular and local shopping platforms and marketplaces, provides detailed API Docs, tech support, and has a 30-day free trial period. Before using all functionality ranges of API2Cart, it is required to develop the integration with it. 

Standard plan: $500/month; Dedicated: $1500/month; Premium: $2500/month; Enterprise: counted individually.

URL  https://api2cart.com/

Summary API Design tools

Working with APIs may seem complicated, as it requires connecting seemingly unrelated applications and making it possible for them to work together. However, due to evolution from SOAP to REST (and soon, likely GraphQL), the process has gotten considerably easier.

The fact that applications use common communication formats like JSON makes it possible for a whole new range of development opportunities. APIs make it possible to create lightweight applications which can easily adapt and traverse the rapidly changing ecosystem of web software.

With the right API design tools, API development and management can become a seamless part of your development process and enable you and your clients to be able to remain agile in today’s competitive environment.