Most Popular and Well-documented APIs
Tags: api, architecture, webdev, programming
Published: 2023-04-10 11:32:16

API design is a crucial part of building any modern software system. Whether you're creating an API for internal use or for public consumption, you need to carefully consider all the elements that go into a well-designed API.

API design can be a complex and challenging task, requiring careful consideration of numerous factors. From designing secure authentication mechanisms to implementing effective pagination and versioning strategies, building a robust and user-friendly API involves grappling with a range of difficult concepts and technical details.

Last year, I had the opportunity to work on [Certifier's public API](https://certifier.me/), and I found myself in need of some inspiration. I wanted to see what other companies were doing with their APIs and learn from their successes and failures. However, I couldn't find a comprehensive list of the most popular and well-documented APIs anywhere online. So, I took it upon myself to do the research and compile my own list of APIs to analyze.

In this blog post, I want to share that list with you. You'll find a total of 30 APIs, sorted alphabetically, each with a brief description and a link to its documentation. Whether you're just starting out with API design or you're a seasoned pro looking for some new ideas, these APIs are sure to inspire you. So, without further ado, let's dive into the world of API design and explore some of the most well-designed and well-documented APIs out there.

1. [Airtable API](https://airtable.com/developers/web/api/introduction) - a cloud-based spreadsheet platform with a powerful API that enables developers to programmatically interact with its database.
2. [Asana API](https://developers.asana.com/docs/overview) - a project management tool with a robust API that allows developers to access and manipulate Asana's data programmatically.
3. [Calendly API](https://developer.calendly.com/api-docs/4b402d5ab3edd-calendly-developer) - a scheduling tool with an API that integrates Calendly into your applications and workflows, allowing users to schedule appointments programmatically.
4. [Chargebee API](https://apidocs.chargebee.com/docs/api) - a subscription billing platform's API that manages subscriptions, customers, invoices, payments, and automates recurring billing and revenue recognition.
5. [ChartMogul API](https://dev.chartmogul.com/docs/introduction) - a business analytics platform's API that tracks and analyzes subscription and recurring revenue metrics, and allows developers to retrieve and manipulate data from ChartMogul programmatically.
6. [Checkout API](https://api-reference.checkout.com/) - a payment gateway's flexible API that processes payments, manages transactions, accepts payments from various methods, and handles refunds and chargebacks.
7. [ClickUp API](https://clickup.com/api/) - a productivity platform's comprehensive API that interacts with ClickUp's data and features programmatically, allowing you to create, read, update, and delete tasks, lists, comments, and perform advanced searches and queries.
8. [Cognito API](https://cognitohq.com/docs/reference) - an identity verification platform's RESTful API that verifies identities, performs background checks, manages authentication and access control for your applications.
9. [DocuSign API](https://developers.docusign.com/) - an e-signature and digital transaction management platform's API that sends, signs, and manages electronic documents programmatically, automates workflows, and integrates with other applications.
10. [Freshdesk API](https://developers.freshdesk.com/api/) - a customer support and helpdesk platform's RESTful API that interacts with Freshdesk's data and features programmatically, allowing you to manage tickets, contacts, agents, and perform advanced searches and filters.
11. [GitHub API](https://docs.github.com/en/rest/quickstart?apiVersion=2022-11-28) - a platform for software development version control using Git. The GitHub API provides various endpoints to interact with repositories, issues, pull requests, and more.
12. [HubSpot API](https://developers.hubspot.com/docs/api/overview) - a marketing, sales, and service software platform with a powerful API that allows developers to integrate and automate various HubSpot features into their own applications.
13. [Intercom API](https://developers.intercom.com/intercom-api-reference/reference/welcome) - a customer messaging platform that allows businesses to communicate with their customers in a personalized way. The Intercom API provides endpoints for managing conversations, users, and events, among others.
14. [MailChimp API](https://mailchimp.com/developer/marketing/api/) - an email marketing platform that allows businesses to create and send newsletters and automated campaigns. The MailChimp API provides endpoints for managing contacts, lists, campaigns, and more.
15. [MessageBird API](https://developers.messagebird.com/api/) - a communication platform that enables businesses to send and receive SMS, voice, and chat messages. The MessageBird API provides various endpoints for messaging, voice, chat, and verification services.
16. [Miro API](https://developers.miro.com/reference/api-reference) - a digital whiteboard platform that allows teams to collaborate and share ideas visually. The Miro API provides endpoints for managing boards, users, and objects, among others.
17. [Notion API](https://developers.notion.com/docs) - a productivity tool that provides a collaborative workspace for notes, tasks, and databases. The Notion API enables developers to access and manipulate data in their Notion accounts, including pages, databases, and users.
18. [PandaDoc API](https://developers.pandadoc.com/reference/about) - a document automation platform that allows businesses to create, send, and track proposals, contracts, and other documents. The PandaDoc API provides endpoints for managing documents, templates, and more.
19. [Sentry API](https://docs.sentry.io/api/) - an error monitoring platform that helps developers identify and fix issues in their applications. The Sentry API provides endpoints for managing projects, issues, releases, and more.
20. [Slack API](https://api.slack.com/docs) - a popular messaging platform that provides APIs for building integrations and chatbots to automate workflows and enhance communication within teams.
21. [Stripe API](https://stripe.com/docs/api) - a payment processing platform that provides APIs for managing online payments and subscriptions, and integrating with e-commerce platforms, marketplaces, and mobile apps.
22. [SurveyMonkey API](https://developer.surveymonkey.com/api/v3/) - an online survey platform that provides APIs for creating, managing, and analyzing surveys, and integrating with other business applications and services.
23. [Twilio API](https://www.twilio.com/docs) - a cloud communication platform that provides APIs for sending and receiving SMS and voice messages, making and receiving phone calls, and building chatbots and other communication tools.
24. [Twitter API](https://developer.twitter.com/en/docs/twitter-api) – a powerful tool that enables developers to programmatically access and interact with Twitter's data, including tweets, user profiles, and trends.
25. [Typeform API](https://www.typeform.com/developers/get-started/) - a platform for creating and sharing online forms and surveys that provides APIs for integrating with other applications and automating workflows.
26. [Vercel API](https://vercel.com/docs) - a cloud platform for deploying and scaling web applications that provides APIs for automating deployment, monitoring, and management tasks.
27. [Webflow API](https://developers.webflow.com/docs) - a platform for building and hosting responsive websites that provides APIs for integrating with other services and automating web design and development workflows.
28. [WonderPush API](https://docs.wonderpush.com/reference/reference-getting-started) - a platform for sending push notifications and in-app messaging to mobile apps and websites that provides APIs for integrating with other applications and services.
29. [Zendesk API](https://developer.zendesk.com/api-reference/) - a customer service and engagement platform that provides APIs for managing support tickets, customer data, and communication channels, and integrating with other business applications and services.
30. [Zoom API](https://developers.zoom.us/docs/api/) - a video conferencing platform that provides APIs for managing virtual meetings, webinars, and video calls, and integrating with other collaboration tools and services.

Personally, I found the APIs from Airtable, Notion, Miro, Stripe, and Vercel to be particularly impressive due to their clear documentation, ease of use, and extensive functionality. However, each API on this list has its own unique strengths and use cases, so I encourage you to explore them all and see what works best for your project.

Additionally, if you're interested in exploring more APIs, I recommend checking out these two resources: "[The GGV Capital API-First Index](https://www.apifirstindex.com/)" and "[How Far API-First Companies Have Come](https://www.apifirst.tech/p/how-far-api-first-companies-have)". And if you want to dive deeper into API design best practices, I recommend the book "[API Design Patterns](https://www.goodreads.com/en/book/show/51192053)" by JJ Geewax, which provides a collection of practical tips and design standards for building web and internal APIs.

Thanks for reading, and happy coding!