I'm currently working on an API-related venture (we buy & grow API-based SaaS).
As part of my market research, I was wondering which are the most popular APIs in the world in 2021. As you might know, there are 2 main online repositories of APIs: RapidAPI.com and ProgrammableWeb. ProgrammableWeb is currently the largest API directory you can find on the web, feat over 24,095 APIs!
Unfortunately you can't really play with the data on ProgrammableWeb itself. They don't eat their own dog food: I can't see any Developer API in their footer (that's usually where you'll find some documentation to programmatically access the data). So I decided to scrape the public data and play with it in a spreadsheet to have a good sense of the market.
Thanks to the no-code magic of Google Sheets, I was able to sort the APIs in the directory by the amount of followers they have on ProgrammableWeb. Here are the 10 most popular APIs in the world based on this follower count.
The #1 on the list if Facebook API, followed by Google Maps API and Twitter API. This Top 10 features two weather APIs. At #10 we spot the Amazon Product Advertising API, which you can use for all sorts of purposes, incl. creating widgets for your Amazon affiliate site. A Covid-related API currently ranks at #23 (NovelCOVID API).
If you crunch the numbers based on the amount of APIs per category listed on ProgrammableWeb, here's the graph you get for 20,000 APIs, showcasing the most popular categories in the directory.
The most popular category is FINANCE (close to 5% of the total), followed by TOOLS (a broad category), PAYMENTS, MESSAGING and E-COMMERCE. In the years to come, we will probably see an increase in the proportion of Artificial Intelligence-related APIs, which represent 0.5% at time of writing (May 2021). This ranking gives you an idea of the most competitive API markets.
If you've developed an API-based SaaS and are willing to sell your product, don't hesitate to contact Indigo Properties, we're currently looking for this type of businesses.