This is an attempt to categorise different APIs scoured from the web which make their resources available for consumption.

*Items marked with are open-source *Items marked with 💸 are trial based APIs

• [Advertising] (#advertising)
• [Analytics] (#analytics)
• [Augmented Reality] (#augmented-reality)
• [Bar Code] (#barcode)
• [Big Data and Analytics] (#big-data-and-analytics)
• [Bitcoin] (#bitcoin/bitcoin-wallets)
• [Captcha] (#captcha)
• [Check In] (#check-in)
• [Data Science] (#data-science)
• [Dictionary] (#dictionary)
• [Fitness] (#fitness)
• [Google] (#google)
• [IoT] (#iot)
• [Login and Authentication] (#login-authentication)
• [Machine Learning] (#machine-learning)
• [Maps] (#maps)
• [Miscellaneous] (#miscellaneous)
• [Music] (#music)
  • [Music Analytics] (#music-analytics)
  • [Music Discovery] (#music-discovery)
  • [Music Identification] (#music-identification)
  • [Music Lyrics] (#music-lyrics)
  • [Music Store] (#music-stores)
• [Natural Language Processing] (#natural-language-processing)
• [Placeholder Images] (#placeholder-images)
• [Places] (#places)
• [Social Media] (#social-media)
• [Source Control] (#source-control)
• [URL Shorteners] (#url-shorteners)
• [Weather] (#weather)
• [More Resouces] (#more-resources)
• [Contribute] (#contributions)

• Google AdSense - Free, flexible way to earn money from your websites, mobile sites, and site search results.
• Amazon Mobile Ads - Monetize across platforms with multiple ad formats.
• Facebook Marketing API - Manage ads and campaigns using the Facebook API.
• Roblox AdService - Show video ads to mobile ROBLOX users in-game for another source of revenue for developers.

• Clicky - Allows you to extract your web site's traffic data into several formats, making it easy to integrate, analyze, or store your data within your own application.
• Woopra - Real-time website analysis tool that targets customer engagement.
• MixPanel - Analytics for mobile and web which helps you analyze the actions people take in your application.
• IBM Digital Analytics - Web Analytics tool often used by e-commerce websites.
• Open Web Analytics - Provides a way to request and work with your data outside of the OWA reporting interface.
• Google Analytics - Google Analytics provides APIs to collect, configure, and report on user-interactions with your online content.
• Amazon Mobile Analytics - Service for collecting, visualizing, and understanding app usage data at scale.
• Flurry - Yahoo’s Flurry provides you with a number of APIs enabling you to export your data.
• Parse - Download recent data to run your own custom analytics.
• Chartie - Free web API that mines the relevant trend patterns from your signal.
• Zoho Reports API - Build powerful reporting and analytical capabilities into your application.
• Localytics - Interface to Localytics analytics platform.

• Wikitude - Wikitude’s all-in-one AR solution includes image recognition & tracking, 3D model rendering, video overlay, location based AR. 💸
• Vuforia - Solid SDK with robust development options. 💸

• Google Barcode - The Barcode API detects barcodes in real-time, on device, in any orientation. It can also detect multiple barcodes at once.

• Ryft - integrate the Ryft ONE’s data analysis capabilities into existing big data environments for faster data analysis and real-time intelligence.
• Google Charts - Free tool with a wide range of capabilities for visualizing data from a website.
• Mongo DB - mongoDB is ideal for developers who want precise control over the final results and processes for handling Big Data.
• Keen IO - Keen IO is a powerful, flexible, and scaleable solution that’s literally Big Data, easy-to-implement and at your fingertips.

• Bitcoin - Find useful resources, guides and reference material for developers.
• Coinbase - Coinbase APIs and developer tools make building bitcoin and blockchain apps much easier.
• Block - The most versatile and secure wallet for all your coins.
• Coinkite - Coinkite's Bitcoin API provides simple and powerful REST integrations for adding bitcoin functions into your business / application.
• bitpay - A simple, RESTful API to the most powerful bitcoin infrastructure on the planet.
• BlockCypher - BlockCypher is the infrastructure fabric for blockchain applications
• biteasy - Biteasy provides the following, free to use, APIs which a developer can use and build its own great applications.
• Bitcoincharts - You can use this API to include markets data in your websites, mobile apps or desktop applets.
• ShapeShift.io - Exchange between cryptocurrencies without an account. Well documented API for easy use.
• Exchange Rates API - Market Prices and exchanges rates api.

• Google reCAPTCHA - ReCAPTCHA lets you embed a CAPTCHA in your web pages in order to protect them against spam and other types of automated abuse.
• Anti-Captcha - Access to Anti-Captcha’s API.

• Facebook Check-In - A check-in made to a location-based Page.
• FourSquare Check-In - Allows you to check in to a place.
• Yahoo GeoPlanet - Geo-enable your applications using Yahoo GeoPlanet.
• Google Places - Access to Google Places’ API.

• Data Science Toolkit - A collection of the best open data sets and open-source tools for data science.

• Merriam-Webster Dictionary API - Gives developers access to a big ass resource of dictionary and thesaurus content as well as specialized medical, Spanish, ESL, and student-friendly vocabulary.
• Wordnik - Dictionary functions.
• Words API - Use it to find definitions for more than 150,000 words.
• Cambridge Dictionaries Online - Access to Cambridge’s custom-developed API. 💸
• Glosbe API - Dictionary API and Translation Memory API description.
• DictService - This Web Service allows you to access dictionary definitions from the dict.org service.

• FitBit - Web API for accessing data from Fitbit activity trackers, Aria scale, and manually entered logs.
• Strava - API for accessing and managing data about athletes, activities and segments.

• Google BigQuery API - A data platform for customers to create, manage, share and query data. v2
• Google Books API - Lets you search for books and manage your Google Books library. v1
• Google Calendar API - Lets you manipulate events and other calendar data. v3
• Google Monitoring API - API for accessing Google Cloud and API monitoring data. v2beta2
• Google CustomSearch API - Lets you search over a website or collection of websites. v1
• Google Drive API - The API to interact with Google Drive. v3
• Google Fitness API - The Fit API. v1
• Google Geonomics API - Provides access to Genomics data. v1beta2
• Gmail API - The Gmail REST API. v1
• Google Classroom API - The Google Classroom API. v1
• The Google Fonts Developer API. - The Google Fonts API helps you add fonts to any web page. v1
• Google Identity Toolkit API. - Help the third party sites to implement federated login. v1

• Zetta - An open source platform built on Node.js for creating IoT servers that run across geo-distributed computers and the cloud.
• Temboo SDK - This platform acts as a layer on top of third-party APIs, using code snippets to trigger complex processes that run through their cloud platform.
• Xively - Uses free and open libraries to let you connect different types of hardware, using a variety of languages to their cloud service.
• ThingSpeak - “Internet of Things” application and API to store and retrieve data from things using HTTP over the Internet or via a Local Area Network.

• Facebook Login for Apps - Secure, fast, convenient way to login in your app/website.
• Twitter Sign-in - Works on websites, iOS, mobile and desktop applications.
• GitHub Authentication - Access to GitHub’s Authentication API.
• LinkedIn - Make it convenient for your users to sign in with their professional identity.
• Google Identity - Build an auth system that will grow with your business and reduce the friction of getting users into your app.
• Instagram - Access to Instagram’s OAuth API.
• PayPal - Enables your customers to sign in to your web site quickly and securely using their PayPal login credentials.
• Salesforce - Salesforce uses the OAuth protocol to allow users of applications to securely access data without having to reveal username and password credentials.
• Firebase - Authentication, analytics, cloud messaging, crash reporting, ads and more.

• IBM Watson - Simplifies the process of preparing data and makes it easier to run predictive analysis.
• Microsoft Azure Machine Learning API - Helps data scientists publish in minutes which once used to take days after they had developed a feasible model.
• Google Prediction API - Cloud-based machine learning and pattern matching tool.
• Amazon MI API - Amazon Machine Learning API simplifies the process of making predictions that require lots of expertise around model building, data cleansing and statistical analysis.
• Big ML - BigML is user-friendly and developer-friendly Machine learning API that mainly concentrates on decision trees.

• Google Maps API - Google Maps APIs are available for Android, iOS, web browsers and through HTTP web services. Clients can be found here.
• Yahoo Maps - Yahoo Maps lets you easily embed rich and interactive maps using your choice of platform.
• Mapbox - Access to MapBox’s API.
• CartoDB - Allows you to generate maps based on data hosted in your CartoDB account.
• Bing Maps - Bing Maps platform provides multiple API options for your application.
• DigitalGlobe - DigitalGlobe Maps API delivers the world's best satellite imagery, straight to your app. #Beta
• Amazon Maps API v2 - Add interactive 3D maps, graphics, and custom overlays to your Fire Tablet and Fire phone apps.
• Yandex - API for installing Yandex.Maps and the necessary tools for working it on your web app or site.
• Scribble - The Scribble Maps API is a cross browser, mobile ready, HTML5/JavaScript, interactive map builder.

• BBC - Variety of BBC APIs with access to interesting data from Radio Labs, programs played on BBC and linking data around the artist played on BBC.
• MuseScore - REST based API which provides music metadata.
• Spreaker - Enables developers to read and write data to Spreaker.
• MixRadio - Provides a set of web APIs and native platform SDKs built around their music catalogues.
• FreeDB - Look up CD information using the freed database.
• QuantOneMusic - Answers the need for digital music data.

• Spotify - Spotify’s Web API lets your applications fetch data from the Spotify music catalog and manage user’s playlists and saved music.
• NPR API - NPR's API is a content API, which essentially provides a structured way for other computer applications to get NPR stories in a predictable, flexible and powerful way.
• Last.fm - The Last.fm API allows anyone to build their own programs using Last.fm data, whether they're on the web, the desktop or mobile devices.
• Sound Cloud - Using the SoundCloud API, you can build applications that take sound on the web to the next level.
• Rhapsody - Access metadata, user’s entire library of music and do much more.

• MusicMetric - Provides summaries, time series data, geographic data, demographic data, along with Sentiment analysis service for text.
• Next Big Sound - API offers a very simple interface to access data from NBS. Ruby wrapper available.

• Rovi - Access to Metadata, search capabilities and recommendations.
• Setlist.fm - The setlist.fm API has been designed to give you easy access to setlist data in order to build fancy websites and other applications.
• Shuffler.fm - Recommends you artists and sites to subscribe. Ruby and Javascript wrappers available.
• TuneFind - Allows developers to enhance their services with song, show, and movie data from TuneFind.

• Acoustid - Supports searching through their fingerprint database.
• Gracenote - Largest source of music and video metadata on the planet.
• Echo Nest - The Echo Nest API allows you to call methods that respond in JSON or XML.

• ChartLyrics Lyrics API - Allows users to search for lyrics using the artist name, song title, or lyric text.
• Muisxmatch - Power your music project by licensing access to the world’s most authoritative lyrics DB.

• iTunes Search - The Search API allows you to place search fields in your website to search for content within the iTunes Store, App Store, iBooks Store and Mac App Store.
• Reverb - Sell and buy music related merchandise.

• TextRazor - Helps you extract and understand the Who, What, Why, and How from your supplied text. #FreeToUse
• AlchemyAPI - IBM Company - Uses NLP and ML algorithms to extract semantic meta-data from content.
• Open Calais - Good entity extraction, no sentiment analysis.
• Semantria - SAAS API based on Lexalytics engine. #Paid
• Datum Box - Datumbox offers a powerful open-source Machine Learning Framework written in Java.
• Wit AI - Provides an intent-based NLP API to easily build text and audio based chat bots.

• PlaceKitten - A quick and simple service for getting pictures of kittens for use as placeholders in your designs or code.
• Placehold - A quick and simple image placeholder service.
• Lorem Pixel - Placeholder images for every case.
• DummyImage - Particularly nice, when compared to some of its competitors, in that it offers a great deal of flexibility.
• Unsplash - Beautiful placeholders using images from the popular Unsplash

• CityGrid - Enables developers to create web and mobile applications that find local businesses, organizations, and points of interest by a variety of search criteria.
• Factual - Providing a places search that can be searched by latitude/longitude, and “where” using full text search query string.
• Foursquare Venue - Providing a places search that can be searched by  hierarchical list of categories, longitude/latitude etc.
• Fwix - Providing a places search that can be searched by latitude/longitude, and text search based upon categories, address, city, province, postal code, country etc
• Google Places API - Providing a places search that can be searched by latitude/longitude, keyword matched against all fields, name of place, type of place restricted by radius.
• Nokia - Providing a JavaScript places search that can be searched by search term, with a detail search for display by JS widget.
• Yahoo GeoPlanet - Providing a places search that can be searched by type, county, state, country, oceans, seas, continents, hierarchy and full text search.
• Yelp - You can search location using geo bounding box, longitude and latitude, neighborhood, address or city and filter listings by “where”, using a list of support categories.
• YP - Providing a places search that can be queried by keyword and longitude/latitude, street address, city, postal code, Neighborhood, state, points of interest or by phone number.

• Instagram - Search photos by location, user, tags, view trending photos, and make custom items.
• Flickr - Search through user Flickr content, contacts, upload or replace photos.
• Google+ - Enables apps to login to Google+ view connections, groups, posts, and contact information.
• LinkedIn - Enables apps to connect to user accounts, data, connections,groups, communications, and social streams.
• Facebook - For ads, games, payments, login, sharing stats, and user data.
• Twitter - Enables an app to interact with most of Twitter’s functions.
• Pinterest - Enables apps to view the most clicked-through or repinned Pins, view related posts, and user profiles.
• Tumblr - Create new ways to use Tumblr with access to content, likes, followers, and drafts.
• FourSquare - Access to FourSquare database and ability to interact with Foursquare users.
• YouTube - Add YouTube functionality to your sites and apps.
• Gravatar - Create profiles and avatars using this web service.
• Weibo - Programmatic access to China’s most popular microblogging site.
• DeviantArt - The largest social networking website for artists and art enthusiasts.
• WeChat - WeChat is a social messaging application that works across different and multiple platform.
• Whatsapp Document Interaction - If your application creates photos, videos or audio notes and you’d like your users to share these media using WhatsApp. #Limited
• Snapchat - PHP library of Snapchat’s private API. #Private
• GoodReads - Allows developers access to Goodreads data in order to help websites or applications that deal with books.
• Telegram - The Telegram API allows you to build your own customized Telegram clients.
• Twitch - The Twitch API enables you to develop your own applications using the rich feature set that Twitch provides.
• Reddit - API to build clients, crawlers, scrapers, and browser extensions.
• Zomato - Zomato APIs give you access to the freshest and most exhaustive information for over 1.5 million restaurants across 10,000 cities globally.
• Delicious - Access to Delicious’s API.
• Vimeo - Access to Vimeo’s API.
• Daily Motion - Build applications centered around DailyMotion.
• EventBrite - The Eventbrite Python SDK makes it trivial to interact with the Eventbrite API.
• Wordpress - Access to Wordpress’ API.
• Imgur - Imgur's API exposes the entire Imgur infrastructure via a standardized programmatic interface.

• GitHub - Build real-world GitHub applications right from authentication, to manipulating results, to combining results with other service.
• GitHub Gists - Access to GitHub’s Gists API.
• SVN - Collection of modular libraries written in the C programming language.
• Mercurial - Access to Mercurial’s API.
• Team Foundation Server - TFS APIs are based on REST, OAuth, Json and service hooks.

• Google URL Shortener - Service that takes long URLs and squeezes them into fewer characters.
• Bitly - Access to Bitly’s API.
• Yourls - Generate or get existing short URLs, with sequential or custom keyword.
• Po.st - Shorten URLs, Expand shortened URLs, see statistics etc.
• Readability - Shorten long URLs and deliver a great reading view with a single, unique URL using the Shortener API.
• Anon.click - Shorten long URLs and optionally protect them with passwords or captcha. No registration required.

• Open Weather - Access current weather data for any location on Earth including over 200,000 cities!
• Yahoo Weather API - Get up-to-date information for any location, including 5-day forecast, wind, atmosphere, astronomy conditions, and more.
• Wunderground API - Reliable data, accurate forecast, & global coverage in 80 languages.
• Forecast - The same API that powers Forecast.io and Dark Sky for iOS.
• AccuWeather - Provides subscribers access to location based weather data via a simple RESTful web interface.
• Weather Source - Powerful Weather API built for systems that demand speed, reliability and heavy load.

• NewStack
• Music Machinery
• Computer Science Zone
• Louis Dorrad

• Programmable Web
• More Awesome APIs
• APIs.guru

Pull requests are welcome. Please adhere to the guidelines.

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