Open Source Api Design Tools

Table of Contents

Introduction
Best API Design Tools
- 1. RapidAPI Design by Paw
- 2. Postman
- 3. Swagger Editor or Swaggerhub
- 4. Mulesoft API Connect
- 5. AsyncAPI Playground
- 6. Stoplight.io
- 7. FastAPI
- 8. Apiary
- 9. Apollo
Conclusion
FAQs
- Is REST API a tool?
- What are the top API design tools?
- What is JSON REST API
- What is the difference between REST API and RESTful API?
- What are the best ways to design REST API?
- Footnotes

Introduction

"If I have seen further it is by standing on the shoulders of Giants."

―The Correspondence Of Isaac Newton

There has been an explosion of available tooling that emerged from cloud computing's growth almost a decade ago. Developers pressing forward to do things better, make things cooler, orslick. The benefit for many has been cheap tools that improve efficiency and work well. Additionally, the open-sourcing of many free tools, frameworks, and projects has increased developer performance, making teams faster.

As tools evolve and others emerge, it isn't easy to keep track of them. Furthermore, it becomes necessary to vet new tools for use because implementing new tools takes time. The API design ecosystem is no different.

Consequently, we have put together a list of some of the best API design tools to help you choose something that works for your design workflow. Also, it's understood that API design does not occur in isolation, so incorporating tools built for collaboration is important.

In this article, we'll discuss a list of API design tools. The features are highlighted along with other relevant, interesting facts. The hope is to take these tools and evaluate them against your organization's goals to find a good fit.

Best API Design Tools

You may recognize some of the top tools if you are coming from our post on API Design. However, you'll find double the tools listed in this post after some of the originals tools already discussed. If you are new to API design, I suggest starting with API Design or How to Design an API, which introduces different API types and acquaints you with the process of designing a (RESTful) API.

Truly, it's difficult to compile a list when choosing from the pool of tools that relate to all the different types of APIs. Regardless, I hope to mitigate the difficulty by taking popularity and scalability into account.

1. RapidAPI Design by Paw

RapidAPI joined up with Paw to add API design to their array of product services. You can get started with RapidAPI Design by Paw for free.

Paw was an API design application specifically used for macOS. Now, they'll support macOS, Linux, Windows, and web for their desktop and cloud application. The tool is accessed in the cloud through RapidAPI or Paw's desktop application.

The image below shows projects and requests synced between both types of the application. All the projects were created online but automatically appear in the desktop application through your account.

paw cloud and paw desktop showing same request

Also, RapidAPI Design with Paw combines:

RapidAPI's intuitive interface designs
Integration with other RapidAPI products for testing, team collaboration, monitoring, and monetization.
Paw's simplified API workflow

The tool is built for flexibility, meaning that it's cross-platform and supports any API type, including REST, SOAP, and GraphQL.

2. Postman

Postman offers API design in their application that helps users define, develop, test, and monitor APIs¹.

The application has an editor to define OpenAPI, RAML, and GraphQL specifications. You can also import specifications that you already have to generate collections.

3. Swagger Editor or Swaggerhub

Swaggerhub is a SmartBear product that is useful for a design-first API approach.

The online tool:

has error feedback when generating specifications
supports automatic mocking
generates interactive documentation while defining the API.

The OpenAPI specification was originally known as the Swagger Specification². In 2016, the specification and Swagger open-source tooling (i.e., Swagger Inspector) were split up when the specification became part of the OpenAPI Initiative³.

Swagger's tooling and specification were supported by Smartbear before the split. Subsequently, Smartbear supports Swagger and offers additional tools for API collaboration, mocking, and documentation. However, the Swagger Editor tool remains open-source. Therefore, you can check out the article on How to Design an API to learn the steps for downloading Swagger Editor from Github and creating a spec.

If you want to use Smartbear's Swaggerhub, the online tool offers a one-user free tier for hosted docs and mocking but quickly jumps up to $75/month for collaborating with three users⁴.

mulesoft logo

4. Mulesoft API Connect

Mulesoft's API Connect supports writing API specifications in OAS or RAML in a guided web interface. Like other platforms, once you have the specification, it can generate documentation, mock APIs, and collections.

Their API designer integrates with other services like Flow Designer or Anypoint Studio. Additionally, they have an interesting feature to build your API specification using prebuilt and reusable API fragments.

Mulesoft has an API modeling framework that can read and write both OAS and RAML. Consequently, there's support for both types of API specifications on the platform⁵. Furthermore, because of the RAML support, their API design software focuses on API fragments, which are part of the RAML specification used to create reusable API blocks.

Browse Mulesoft Alternatives

5. AsyncAPI Playground

The AsyncAPI specification is the industry standard for asynchronous APIs that are part of event-driven architectures⁶. Additionally, the specification was adapted from the OpenAPI specification, but for EDAs⁷.

One of the AsyncAPI initiative tools is a playground to generate a YAML file and see the WebSocket API's documentation on an adjacent screen. Although the playground is useful, there are other helpful tools:

Generator – generate documentation or code
Parsers – parse AsyncAPI documents
Github Actions

The initiative is open-source, so you can expect to use all the tools for free in designing your event-driven APIs!

6. Stoplight.io

Stoplight is an API design platform available in the cloud or on a desktop. The platform supports API design, mocking, documentation, governance, visibility, collaboration, and API development⁸.

stoplight dashboard

The tool has a nice UI for coding an OpenAPI spec or using a form to create the specification blocks. As is the case with most of the tools on the list, there is additional open-source tooling:

Spectral – API style guides for API consistency
Prism – API mocking
Elements – Web components for custom API documentation

Stoplight integrates well with Git and focuses on API style guides, user interface, and customized documentation.

7. FastAPI

FastAPI is an open-source API framework building, documenting, and typing APIs with the Python programming language. The framework claims to beon par in performance with NodeJS and Go (other popular backend programming languages)⁹.

You may be asking,why is an API framework on the list? As discussed in the API Design article, two approaches to designing an API are code-first and design-first. Many of the tools on this list focus on design-first approaches, where we create a spec before building the API.

Alternatively, a code-first approach uses business requirements to create an API before generating a specification. FastAPI, although only for Python APIs, automatically generates documentation from your code and hosts the documentation at the /docs or/redoc URL of the API server.

Furthermore, the framework publishes an OpenAPI file in JSON at a different URL. This is useful for CI/CD integrations or porting the spec to other tools.

8. Apiary

Apiary is an API design and collaboration tool that Oracle acquired in 2017¹⁰. The tool uses the API Blueprint specification syntax for describing the API.

API Blueprint is an alternative structure for defining REST APIs and was released shortly after Swagger was created in 2014³. The syntax is noticeably different than YAML (used for OpenAPI) and RAML, using syntax more similar to Markdown.

Once the API Blueprint is written, the spec generates documentation, publishes documentation on Apiary, or builds a mock server to test the design. Additionally, in the collaboration process, developers can send requests through Apiary's proxy servers to help with debugging and inspecting requests¹¹.

9. Apollo

You'll often find that API client tools have support for REST and GraphQL APIs. However, other options exist for helping a team develop and integrate GraphQL into their existing data sources.

Furthermore, because GraphQL is an abstraction layer around a data source, there are ways to create a GraphQL layer between your front-end and back-end services. This is where Apollo comes into play.

Apollo has a studio in the cloud, CLI, and editor extensions (Visual Studio Code) to help teams create GraphQL data layers out of existing REST APIs. Therefore, you can get two APIs for only designing one. If you want to try GraphQL and have an existing REST API or understand how to design REST APIs, Apollo could be a place to start.

Conclusion

This article took a look at some of the best API design tools. Some had similar features with only a few variations, and others are for completely different use cases. It's important to remember that tools evolve, and most are constantly adding features and integrations. So, check in with the tools that interest you and see how well they fit!

I hope this article gets you on the right path, and with the proper tools, for continuing your work in API design!

FAQs

Is REST API a tool?

A REST API is an application programming interface that follows the Representational State Transfer architecture (also known as REST). Therefore, it's not a tool, but a type of API.

What are the top API design tools?

The top API design tools are RapidAPI and Paw, Postman, Swagger Editor, API Connect, AsyncAPI Playground, Stoplight.io, FastAPI, Apiary, and Apollo.

What is JSON REST API

Similar to the REST API described above, a JSON REST API uses JSON, Javascript Object Notation, to transfer data. JSON is a lightweight data exchange format.

What is the difference between REST API and RESTful API?

These two terms are interchangeable. They both refer to an API that uses Representation State Transfer to exchange data between a client and source.

What are the best ways to design REST API?

The best way to design a REST API is with a specification. Common REST API specifications include OpenAPI, RAML, and API Blueprint. The different styles may be important because some design tools favor a certain style, but you can often find ways to convert between the different formats.

Footnotes

¹ "API Design: How to Use Postman to Design, Develop, and Test APIs."Postman, www.postman.com/api-design/. Accessed Apr. 9, 2021.

² "OpenAPI Specification." Wikipedia, 29 May 2020, en.wikipedia.org/wiki/OpenAPI_Specification. Accessed Apr. 9, 2021.

³ "Swagger (Software)." Wikipedia, 10 Jan. 2021, en.wikipedia.org/wiki/Swagger_(software). Accessed 9 Apr. 2021.

⁴ "Flexible Pricing for Teams & Enterprises | SwaggerHub."Swagger.io, 2021, swagger.io/tools/swaggerhub/pricing/. Accessed Apr. 9, 2021.

⁵ "Best Practices for API Design | API Design Principles | RapidAPI." The Last Call – RapidAPI Blog, 29 Mar. 2021, rapidapi.com/blog/api-design-best-practices-principles/. Accessed 9 Apr. 2021.

⁶ "AsyncAPI Initiative."AsynchAPI Initiative, www.asyncapi.com/. Accessed 9 Apr. 2021.

⁷ "Coming from OpenAPI | AsyncAPI Initiative." 605c657882e81fb31cdebd4f–Asyncapi-Website.netlify.app, www.asyncapi.com/docs/getting-started/coming-from-openapi. Accessed 9 Apr. 2021.

⁸ "OpenAPI API Driven Development | Develop APIs with Stoplight." Stoplight.io, stoplight.io/api-development/. Accessed 9 Apr. 2021.

⁹ "FastAPI." Fastapi.tiangolo.com, fastapi.tiangolo.com. Accessed 9 Apr. 2021.

¹⁰ "Company | Apiary." Apiary.io, apiary.io/company. Accessed 9 Apr. 2021.

¹¹"Apiary | How Apiary Works: Fast-Track Your API Design Process." Apiary.io, apiary.io/how-apiary-works. Accessed 9 Apr. 2021.