Articles
10 interesting open REST APIs for your next project
Let’s face it, the world doesn’t need another calculator or to-do list app. Instead, think about building new and interesting applications around open REST APIs.

Most developers have side or personal pet projects. But how to start making such a new application? It’s scary to sit in front of an empty IDE wondering what to do…. There are thousands of blog posts with tips to start programming a calculator, a to-do list, or a social network clone. While they can certainly be useful for learning about the tech stack, let’s face it – the world doesn’t need another calculator or to-do list app. Instead, think about building new and interesting applications around open REST APIs.
What is REST API?
The Representable State Transfer (REST) Application Programming Interface (API) provides a set of methods that a programmer can use over HTTP to send and receive data. Because these methods use HTTP, any programming language or app can work with them.
There are now thousands of REST APIs available on almost every possible site. Usually for public data like weather or stock markets, you can find dozens of different APIs available to use. Many popular web platforms such as Facebook and Twitter also provide developer APIs. Some of the proprietary APIs have limits on how many times they can be called. Many require registration and obtaining a private key. The most secure APIs require OAuth to be configured for secure user login.
You can find a huge list of public APIs on GitHub, and an even larger list exists on RapidAPI.
10 Interesting REST APIs
This list, of course, is not exhaustive, but I just find some of them especially interesting and worthy of your side projects. All of them are absolutely free and do not require anything other than getting an API key – no need to figure out how to handle OAuth or pay to use them.
- PokeAPI – The biggest media franchise of all time has an easy way to get data on 800+ Pokémon.
- NASA API – Get data on asteroids, galaxies and more.
- Open Food Facts – Huge amount of food data from all over the world.
- Transloc OpenAPI – Get live public transportation data for cities and campuses.
- Urban Dictionary API – It’s amazing what slang people use!
- Merriam Webster Dictionary API – For those who need definitions and synonyms for real words.
- numbers API – Interesting facts and questions about numbers.
- weatherbit API – Current and historical weather data.
- US government data API – A fairly large set of data about the United States – agriculture, health care, public safety, etc.
- Bible API – The best selling book of all time. Greatest story.
What to do with this APIs
All of these public APIs are great, but having a list of interesting data sources doesn’t inherently solve the problem of a new project.
It’s best to start by simply getting and displaying data. Maybe show the Pokémon of the day or the definition of the typed word. For a more creative approach, try taking your data and adding visuals to it, such as associating temperature with a color or displaying a bus in motion.
The hardest part is just getting started. Once you’ve overcome the initial hurdles in getting and displaying information, I’m sure you’ll come up with plenty of possibilities for your project!
