9. Payments: Stripe
This one will come as no surprise, but Stripe owns the space for online payments. From Shopify to the majority of SaaS startups, it is prolific across the web. Over time, Stripe has added many more products beyond online payments and now offers also things like checkout flows, in-person terminals, invoicing and more.
8. SMS Gateway: Twilio
Sometimes you just need to send a text message. Authentication and notifications are the most common usecases, but sometimes it can also be an interesting interface for your users. But somehow, these text messages need to be sent: this is where Twilio comes in. Just as Stripe, Twilio has expanded far beyond their initial product, now also offering voice and video products which can be integrated into your app through their extensive API collection.
7. Weather: AccuWeather
AccuWeather is not just a popular weather app: They also have a REST API that can help you get the same weather data into your app. The free version allows for 50 API calls per day, daily forecasts for five days into the future and hourly forecasts for the next 12 hours. Various pricing plans allow for more features and requests as needed.
6. Maps: OpenStreetMap
While Google Maps are a more popular option, OpenStreetMap has a great API with extensive documentation and on top of it - it's free, both as in free beer and as in freedom. At api.openstreetmap.org you can request map segments, display routes from GPX files and much more. All you need is an account to get started.
Slack is a major player in the enterpise communications space - and since it is so widely used, it can make for an amazing notification tool. The Slack API allows you to do just that and much more: from automating interactions within your company to deliverying notifications to teams and individuals, they have you covered. On top, maybe you might even want to build a Slack addon for others to use?
4. Countries GraphQL API
While most of the other APIs on this list are operated by startups or enterprises, Countries has been developed by Trevor Blades, a Canadian developer. With its beautiful syntax, it allows you to easily get currency, language, emoji, capital city and more of any country.
3. Github and Gitlab GraphQL API
If you ever wanted to automate aspects of your CI/CD pipeline that go beyond the basics, both Github and Gitlab have great GraphQL APIs to help you gather information about contributions or projects, manage users across organisations, post comments to issue discussions and much much more.
2. Video: MUX
When you need to interact with video at scale, MUX is the API you need. They allow hosting and streaming videos, automate the processing, live streams and have deep management integrations, from usage tracking to video analytics and CMS integration. They also offer $20 free credits for getting started.
The vastness of space is still waiting to be conquered. If you want a front row seat to SpaceX's efforts, this API can help you with information about launches, mission names, rocket types payload and much much more. The SpaceX GraphQL API is well thought out and super extensive. A handy query explorer further helps to find what data is available and can help you build cool analysis tools for anything SpaceX related.
0. Text Summarisation (and more to come): Neuralfinity's Computational Magic
Yes, of course we included ourselves in this list, but for a reason: We have yet to see anyone else make text summary this easy. Our GraphQL API is familiar to any developer who worked with GraphQL before, it is a pure web API, so fully independent of programming languages, as it requires no SDKs at all. On top of that, we don't need any datasets from you for fine tuning, as all our models are specifically optimised to be generalisable across many domains for any particular task.