An Application Programming Interface (API) can be defined as an intermediary bridge of communication between two or more separate applications, often provided to the developers as a service. A historical weather API, for example, enables a typical weather app to interact with stored weather data from the past and collect the information necessary.
Now, the actual usage of an API can vary widely, therefore it completely depends on what the developer is looking to do. That being said, there are a few widely used APIs among the tens of thousands that are found to be of most use to software developers. Today, we have a brief list of such Application Programming Interfaces which you will likely find to be quite useful too.
Google Maps API Suite
This denotes the entire Google Maps API suite, including the Google Maps Geocoding API. Simply put, any and all developers who are working in location app development will find this public suite to be an indispensable one.
If your project entails unfurling URLs or scraping sites, Opengraph.io is very easy to use solution worth considering. It supports unfurling detailed descriptions from the URL, as well as the unfurling of media content, titles and even product information from any website you need the info from.
Weather API (JSON and XML)
Typically made for developers who work in the development of enterprise-grade weather and geolocation software, the Historical Weather API is considered to be the ultimate solution for collecting and syncing past, present and future historical weather API data from nearly all locations on the planet.
From time zone and astronomy APIs, to mapping and geolocation APIs, the XML and JSON Weather API has everything that a developer may need to work in direct or associated sectors linked to weather and geolocation.
Google Play Store API
This is one of the most important application programming interfaces that a mobile app developer may need access to, for staying up to date with relevant ratings, reviews, rankings, product details, and more.
Microsoft Computer Vision API
There is likely no better API out there with more enhanced algorithms for image and OCR response data processing than the Microsoft Computer Vision.
Web Search API
Just as broad and wide in the application as the name suggests, Web Search is a one-shot application programming interface to get access to literally billions of webpages with their respective web content. It offers features such as pagination, news post-filtration by date, advanced search filters, specific site searches, and image thumbnails.
The Imgur API leaves nothing to one’s imagination since developers can use it to access the whole web infrastructure. In fact, the standardized programmatic interface enables you to do so with the most common programming languages, quite similar to how it is with the Twitter API or the Amazon S3 API.
Facebook API Suite
While this one is as obvious as anything else, it still deserves special mention due to its sheer validity, relevance, and usefulness. A complete application programming interface for social media marketing and data analysis, the API returns are in the popular JSON format, and Facebook utilizes the RESTful protocol now.
Twitter API, YouTube API, and Instagram API also deserve special mention for social media-centric app developers and depending on the platform of your project, these might be more useful than even Facebook.