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Shortlist of the 12 Best API Tools

Here’s my list of the top 12 tools for API integration and creation, with more options below.

  1. RapidAPI - Best API marketplace
  2. Theneo - Best for AI-assisted API documentation
  3. apiDOC - Best for transforming API annotations into documentation
  4. Stoplight - Best for fast API creation
  5. Celigo - Best for API automation
  6. Azure API Management - Best for hybrid and multi-cloud API management
  7. IBM API Connect - Best for API lifecycle management
  8. OpenAPI Generator - Best for generating API code
  9. ReadMe - Best for creating interactive API documentation
  10. Apigee - Best for Google Cloud API management
  11. MuleSoft - Best for API delivery and deployment
  12. Axway - Best for universal API management

Whether you’re looking for the best platform to find new APIs or to create and promote your own, the number of options on the market can feel overwhelming.

To help make your selection easier, I’ve given detailed overviews and key reasons for why each API tool made my shortlist, so you can get the right tool for your company’s unique needs while saving time and money.

What is an API Tool?

An Application Programming Interface (API) is a software interface that enables two or more applications to communicate with each other. 

APIs enhance the functionality of applications without forcing developers to build new features from scratch. They make it possible for one application to leverage the capabilities of another in a safe, secure, and efficient manner.

An API tool is an application designed to help you make the most of your APIs by assisting with design and development, automated and manual testing, publishing, and monetizing the APIs that you produce. You can also use API tools to browse other people's APIs and integrate them into your own system, such as your multi-cloud or on-premise environment.

Overview of the 12 Best API Tools

Let's dive deeper to explore the unique features, benefits, and pricing models of the 12 best API tools you can use right now.

1. RapidAPI – Best API marketplace

RapidAPI Hub
Introduction to the RapidAPI Hub for finding and downloading APIs. (Source)

RapidAPI is the largest API marketplace in the world, with more than 4 million developers using the platform to consume APIs and more than 40 thousand APIs currently in the hub.

RapidAPI is great for API providers, thanks to its built-in developer portal and large user base. It is also great for consumer developers, as you’ll find plenty of APIs in broad categories to choose from, ranging from weather and transportation to accounting and music.

Why I Picked RapidAPI

I selected RapidAPI Marketplace because I liked how easy it was to browse and find the APIs you need, right down to their category. There are thousands of APIs to choose from, meaning you are nearly guaranteed to find one that meets your unique requirements. 

Another great thing about RapidAPI is that you can test the response times and functionality of your chosen APIs before you integrate them into your system, giving you the assurance that the ones you choose will work properly. 

RapidAPI Standout Features

I noted a wide range of features in RapidAPI, with tools to help you design, develop, test, and publish your APIs, as well as find and connect APIs to your system. 

While many of these features are standard for most API tools, what sets RapidAPI apart is its ease of use and large user base. Whether you are an API provider or consumer developer, there is an audience for your next API, and there are more than 40,000 APIs ready to use.

Pricing: From $10/month

Trial: Free plan available


  • Hundreds of different API categories
  • Over 40,000 APIs for consumer developers to find and connect to
  • Integrated API design, development, and data-driven testing tools


  • User interface can be challenging for newcomers, especially when designing APIs
  • Some published APIs can still present issues and not perform as expected

2. Theneo – Best AI-assisted API documentation

Theneo API documentation tool
TheneoAPI provides AI-suggested descriptions and summaries for your API documentation. (Source)

Theneo is an API documentation tool that reviews your API collection and provides AI-generated descriptions and summaries. Theneo also has a built-in editor called Ease, which can help you create beautiful and easy-to-read documentation.

Why I Picked Theneo

Theneo stood out to me because it helps API providers solve a unique problem that many other API tools do not address as well: documentation. Theneo reduces manual documentation by providing AI-generated descriptions and summaries, which you can use to generate content and improve your existing content.

Theneo Standout Features

The best aspect of Theneo is the built-in AI, which allows you to generate new content to use as a documentation baseline, and can also increase the quality of your final documentation via AI-powered suggestions to improve flow, grammar, punctuation, and consistency. Theneo is also compatible with Github, Swagger, and Postman.

Pricing: From $120/month

Trial: Free plan available


  • Powerful AI tools for content generation and editing suggestions
  • Supports OpenAPI, Postman, SOAP API, GraphQL, and AsyncAPI
  • Custom API branding capabilities


  • Limited compatibility with major programming languages
  • Can only be updated a set number of times per day

3. apiDoc – Best for transforming API annotations into documentation

apiDoc documentation for APIs
apiDoc uses your source code annotations to create API documentation. (Source)

apiDoc is an API documentation tool that you add documentation straight to your source code through annotations. This eliminates the need to use a separate tool or third-party library to generate and manage your documentation. 

Why I chose apiDoc

I appreciated apiDoc because of how it eases the documentation process, and can help both internal developers and users better understand your product. The workflow feels streamlined because you manage everything in your source code without the need for a separate tool, making it easier to keep your internal and external documentation in sync.

apiDoc Standout Features

apiDoc is an all-in-one package, meaning you simply download the apiDoc files, place them in a directory, and install them from your source code. You then link your code to apiDoc, and – tada! – it will generate documentation. Also, you can attach version numbers to your projects, making it easy to track changes and compare versions.

Pricing: Free to use


  • Easily manage API documentation within your source code
  • Compatible with most major programming languages
  • Easy to track API changes and compare versions


  • Only compatible with RESTful web APIs
  • Relatively small user base and community support 

4. Stoplight – Best for fast API creation

Using Stoplight to design APIs
Stoplight helps you develop quality APIs quickly and easily. (Source)

Stoplight is an API tool designed to help you design, document, and build APIs quickly and easily. The service places a strong emphasis on team collaboration, project visibility, and governance.

Why I chose Stoplight

I chose Stoplight for its intuitive interface and full API lifecycle support. The visual and collaborative editor is clean, easy to use, and provides clear instructions on how to perform different tasks and functions. I also appreciated Stoplight’s detailed resource center, with instructional guides in written, audio, and video format.

Stoplight Standout Features

Spotlight’s standout features include the Stoplight Studio, which has an easy-to-use interface that is accessible to both technical and non-technical staff. This helps you design APIs in mere minutes and then use virtual mock servers to test your designs and receive feedback from stakeholders.

Stoplight can also help you incorporate governance by letting you use predefined or custom guidelines as a reference.

Pricing: From $39/3 users/month

Trial: Free plan available


  • Complete API lifecycle management, from design to documentation to compliance
  • Useful and easy-to-follow learning materials in written, audio, and video formats
  • Open-source API tools for mocking, lifting, and documentation


  • Expensive premium plans
  • UI can be hard to navigate as projects become more complex

5. Celigo – Best for API automation

Using Celigo for API automation
Celigo helps you automate your business process. (Source)

Celigo is an Integration-Platform-as-a-Service (IPaaS) that helps you connect and manage APIs, automate business processes, and sync data across multiple cloud and on-premise environments. 

Why I Chose Celigo

Despite how feature-rich Celigo is, I was surprised by how easy it was to learn. The instructor-led training sessions let you engage with a professional one-on-one, where they cover a range of topics – i.e., establishing connections, resolving errors during flows – and let you ask questions. 

Celigo also makes it easy for you to automate business processes using pre-built automations that follow industry best practices.

Celigo Standout Features

I appreciated that Celigo has features to assist with virtually every aspect of the API management process, from development to integration and email and Excel integration. For technical users, you can develop your own integrations with custom code. 

You can also browse 100+ APIs from official vendors like Microsoft and Salesforce and use universal connectors for over 100,000 apps.

Pricing: Pricing upon request

Trial: Free trial available


  • Easy to learn and use
  • Huge range of pre-built apps and business logic flows
  • Strong documentation and customer support


  • Custom pricing can make it hard to predict ongoing costs
  • Over-reliance on universal connectors can lead to issues with third-party APIs

6. Azure API Management – Best for hybrid and multi-cloud API management

Azure API management's dashboard
Azure API Management makes unified API management easy. (Source)

Microsoft Azure API Management is an API management tool intended to help deploy and manage APIs on the Microsoft Azure platform, along with other clouds and on-premises environments. You can use Azure API Management to control data access, transform legacy web services into RESTful APIs, and incorporate security and compliance.

Why I Chose Azure API Management

The first thing that stood out to me was the pay-as-you-go pricing model, which lets you pay only for the time that you spend on the service. I also appreciated the robust security and customization features. You can control how your data appears to different users (i.e., employees, visitors, customers), implement strict authorization and authentication standards, and customize the developer portal with your own branding to help boost API discoverability. 

Azure API Management Standout Features

Azure API Management lets you deploy self-hosted gateways, meaning gateways are placed in the same environments that the APIs are hosted in. As a result, you can more easily streamline the flow of traffic, which helps reduce latency and lower data transfer costs. 

You can also use the custom developer portal to personalize the branding of your API. And while that feature isn’t unique to Azure, the Microsoft branding adds an extra level of authenticity to your API.

Pricing: From $48.04/month

Trial:: Free trial available


  • Custom developer portal to promote products to internal teams and external partners
  • Comprehensive security measures control users’ data access
  • Manages assets across multiple environments, including in the cloud and on-premises


  • Flexible pricing can make it hard for businesses to manage fluctuating costs
  • Integrating with apps outside of the Azure platform can be difficult

7. IBM API Connect – Best for API lifecycle management

Interface of IBM API Connect
IBM API Connect lets you secure and manage APIs throughout the entire lifecycle. (Source)

IBM API Connect is an API creation and management tool that is designed with security and multi-cloud API lifecycle management in mind. It provides an intuitive, easy-to-use experience for API providers and consumer developers, with a developer portal that lets you create, secure, socialize, and monetize your APIs.

Why I Chose IBM API Connect

If you’re looking for a full-service API lifecycle management tool, I found that IBM API Connect has everything you’d typically need, including API creation, API testing tools, and analytics. The analytics feature is particularly useful as it helps you better understand who is downloading your APIs, how they are using them, and what can be done to improve the user experience. 

IBM API Connect Standout Features

IBM API Connect is notable for its commitment to enhancing the lifecycle management experience. On the creation side, you get auto-generated API models, visual API creation, and support for REST APIs, SOAP web services, MySQL, MongoDB, and more connectors. While on the managing side, you get several instances of API managers, developer portals, and a policy assembly UX for easy compliance. 

Pricing: From $83/month

Trial: Free 30-day trial


  • Huge range of API lifecycle management features
  • Unique emphasis on socialization to help boost API visibility and user engagement
  • Self-service developer tools help API deployment strategies for the whole API lifecycle


  • Steep learning curve
  • Short free trial period

8. OpenAPI Generator – Best for generating API code

OpenAPI Generator for generating API code
OpenAPI Generator helps you generate clients, servers, and documentation from OpenAPI documents. (Source)

OpenAPI Generator is an API management tool that allows you to generate clients, servers, and documentation from OpenAPI documents. OpenAPI Generator has more than 50 client generators, which you can use to generate and implement code into your API. 

Why I Chose OpenAPI Generator

I selected OpenAPI as a recommendation for anyone who needs powerful API generation tools. Whether you’re building a MySQL database or server stub, OpenAPI Generator helps reduce manual coding errors by automatically generating code that meets your specifications. You can also customize the code you generate based on the functionalities you need, such as generating documentation in Cwiki and HTML formats.

OpenAPI Generator Standout Features

OpenAPI Generator has more than 50 client generators for Android, Dart, Ruby, Rust, and many more. It is also very customizable, letting you transform templates with additional static documentation and custom tooling scripts. OpenAPI Generator also supports listing generators, “Meta” generators, and validation of Open API - both 2.0 and 3.0 versions.

Pricing: Free to use


  • Automatic code generator helps reduce manual coding errors
  • More than 50 client generators and more than 40 different languages and technologies for server stubs
  • Active Slack community for troubleshooting


  • Automatically generated code still needs reviewing to ensure it works
  • Limited security features

9. ReadMe – Best for creating interactive API documentation

ReadME API developer hub
ReadMe turns your standard API documentation into interactive hubs. (Source)

ReadMe is an API documentation platform that has the unique ability to convert standard API documentation into interactive hubs. It has a wealth of advanced features to help you create secure, up-to-date, and beautiful documentation, as well as improve the user experience for consumer developers.

Why I Chose ReadMe

Most API documentation platforms restrict you to formats like HTML and PDF. But ReadMe stood out to me because it allows you to transform your standard API documentation into a format that is more interactive, user-friendly, and flexible than any other. This helps you quickly create and launch APIs, as well as respond to feedback, troubleshoot issues, and implement API requests.

ReadMe Standout Features

One of the ReadMe features I most appreciated was the “Try It” playground, a place where consumer developers can test APIs in a secure, virtual environment in real-time. This makes it easy for people to see how your API works and how well it integrates with their system before they commit to the continuous integration process.

Pricing: From $99/per project/month

Trial: Free plan available


  • Create real-time, interactive API documentation hubs
  • "Try It" playground lets developers try your API before integration
  • Custom discussion forums facilitate communication between your team and developers


  • Pricing model is a bit unclear on exactly what each plan offers
  • The content editing experience feels limited compared to Markdown

10. Apigee - Best for Google Cloud API management

Apigee for Google Cloud API management
Apigee lets you develop and manage RESTful web services on Google Cloud. (Source)

Apigee is an API tool for developing and managing REST- and HTTP-based APIs. The Apigee platform is unique for its use of API proxies, where consumer developers make HTTP requests to API proxies instead of interacting directly with your services. This arrangement shields developers from your backend, preventing backend code changes.

Why I Chose Apigee

I chose Apigee because it helps API providers make backend changes to their APIs while maintaining a consistent frontend. This means you can make changes to your services without worrying about negatively impacting the user experience. In addition, Apigee is owned and operated by Google, so consumer developers can connect any Google-based applications to Apigee with ease.   

Apigee Standout Features

In Apigee you’ll find a feature-rich dashboard that gives you a bird’s eye view of your API environments. You can control and monitor API traffic, investigate traffic spikes, optimize API performance, and identify potential areas of improvement. You can also customize the analytics data that you collect as it relates to your API, developers, and products. 

Pricing: From $1.025 per Apigee gateway node per hour

Trial: Free 60-day trial period


  • Native Google Cloud integration
  • Simple and straightforward setup and deployment process
  • Automated API security scans with machine learning abuse detection.


  • More expensive than Azure API Management.
  • Can be demanding on infrastructure, resulting in lag and other performance issues.

11. MuleSoft Anypoint Platform – Best for API delivery and deployment

MuleSoft for universal API management
MuleSoft specializes in universal API management across multiple clouds. (Source)

MuleSoft is an API development, management, and integration platform. It helps you to  quickly build APIs from scratch with pre-built assets, as well as to discover and connect to APIs made by third parties.

Why I Chose MuleSoft

I recommended MuleSoft because of its powerful API development tools, seamless integration capabilities, and ease of use. I was particularly impressed by how flexible the integration tools are, which let you connect to both newer and legacy systems at the same time. MuleSoft is also owned by Salesforce, so you can incorporate the Salesforce products into your workflow.

MuleSoft Standout Features

One feature that sets MuleSoft apart is the Anypoint Flex Gateway. Designed with speed and performance in mind, the Gateway lets you manage and secure APIs running from anywhere, including the most demanding applications across multiple cloud environments. MulesSoft also has an intuitive user interface featuring drag-and-drop tools and pre-built connectors to streamline the development and integration process.

Pricing: Inquire for custom quotes

Trial: Free 30-day trial period


  • Powerful API development tools that are easy to use.
  • Seamless integration with Salesforce and Workforce portfolio of products.
  • Can be run virtually in any architecture or environment.


  • Lack of documentation and steep learning curve.
  • More features than what most API providers and consumer developers need.

12. Axway Amplify API Management – Best for universal API management

Amplify API management platform
Axway Amplify is designed to bring API creators and consumers together. (Source)

Axway Amplify is an API management platform that features an integrated marketplace, management and integration service, and open banking solution. Amplify consists of an open platform that lets you publish, validate, and govern APIs in both multi-cloud and on-premise environments. 

Why I Chose Axway Amplify

Axway Amplify caught my attention for its innovative use of automation, which enables you to automate the process of finding, reusing, and applying governance standards to APIs across multiple cloud and on-premise environments. It also lets you easily monitor the usage and performance of your APIs while providing detailed analytics for the full API lifecycle.

Axway Amplify Standout Features

Features that make Axway Amplify unique include the Open Banking solution. Open Banking allows banks to share financial details in a safe, secure, and simple manner. I appreciated how this tool helps you reap all the benefits that Open Banking has to offer, such as widespread integration throughout the financial ecosystem.

Pricing: Inquire for custom quotes

Trial: No free trial


  • Strong documentation and customer support
  • Detailed analytics and API performance monitoring capabilities
  • Unique emphasis on Open Banking solutions


  • Over-abundance of features can be overwhelming
  • Can be expensive for businesses on a limited budget

Here's a list of the API tools that didn't quite make my top 12 list. If you are after a specific feature or function that you couldn't find in the main list, one of these API tools could be up your alley.

  1. Tyk - Best open-source API
  2. Software AG - Best for seamless data integration
  3. Boomi - Best API management for enterprises
  4. Cleo - Best for EDI and API automation 
  5. Swagger - Best for supporting OpenAPIs at scale
  6. AsyncAPI - Best for building and maintaining event-driven architecture 
  7. Flowgear - Best for creating workflows
  8. FastAPI - Best for building APIs with Python
  9. SoapUI - Best API testing tool
  10. REST Assured - Best for validating REST services

Selection Criteria For API Testing Tools

Here's a quick breakdown of the criteria that I followed to come up with my list of the 12 best API tools.

Core Functionality

Most API tools are multi-purpose platforms that help users build and deploy their own APIs, as well as find and integrate third-party APIs into their own applications. I made sure to choose API tools that serve a variety of needs for both API developers and customers, so each one must help you do one or more of the following tasks:

  • Find and assess new APIs to meet your needs
  • Integrate APIs into your software
  • Create effective software documentation for your APIS
  • Design and develop new APIs and features
  • Publish and promote your custom APIs

Key Features

To help make sure you find software that’s a cut above the rest, I looked for options that not only provide the above core functionalities, but do so with distinctive features, such as:

  • Automation: The tool should make your workflow easier by streamlining processes with pre-build components, AI, or other generative capabilities.
  • Monitoring: The tool should provide robust reporting options and make it easy to keep track of your project’s status
  • Flexibility: The tool should be customizable and able to assist users in a wide range of use cases. 

User Friendliness

The more user-friendly an API tool is, the more value a developer or customer can get from it in a given time. That's why I chose API tools that have a user-friendly design interface and are accessible to people of all technical backgrounds. 

Documentation and Support

When reviewing these API testing tools, I checked to see how well-supported they were. This included reviewing their official documentation, tutorials, and guides. I looked especially for built-in tutorials to comfortably ease new users into the workflow. By doing so, I got a better idea of how accessible each tool was to the average user.

People Also Ask

Below is a quick breakdown of the most common questions people ask when searching for API tools.

API Tool Selection Made Easy

Whether you are a developer or customer, choosing the best API tools for your project is very important. They each have unique features, strengths and weaknesses, and pricing models, which influence what each tool can do and how much value they can add to your project. 

Hopefully, this article will help you better understand the differences between each vendor so that you can make an informed choice for your business.

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By Paulo Gardini Miguel

Paulo is the Director of Technology at the rapidly growing media tech company BWZ. Prior to that, he worked as a Software Engineering Manager and then Head Of Technology at Navegg, Latin America’s largest data marketplace, and as Full Stack Engineer at MapLink, which provides geolocation APIs as a service. Paulo draws insight from years of experience serving as an infrastructure architect, team leader, and product developer in rapidly scaling web environments. He’s driven to share his expertise with other technology leaders to help them build great teams, improve performance, optimize resources, and create foundations for scalability.