Single purpose API
Transloadit offers media upload, modification, and storage as a service for developers who need that functionality (or, as Transloadit's homepage puts it, "geeks who run web or mobile applications") but don't want to worry about it themselves. There aren't too many moving parts to it, but they're ones a lot of applications make use of. The Transloadit API's main functions include: file upload, image resizing, video file encoding, image thumbnail creations, and file storage on Amazon S3.
C2Call Low Level
||The C2Call Low Level API integrates chat, messaging, voice, and video into web and mobile applications. It is available in JSON architecture with OAuth as authentication method. Usage aims to...||Chat||10.10.2016|
||This REST API lets you access your submission and organization data and allows you to start accepting text, audio, video, image, or link submissions. It returns submissions, categories, submitters,...||Publishing||10.04.2016|
||VocaDB offers an international music database dedicated to singing synthesizers such as Vocaloid and UTAU. The database contains information related to artists, albums, and music videos. The API is...||Music||10.03.2016|
||TinEye's MatchEngine API offers image recognition capabilities that can find duplicates and derivatives of existing images in an image collection. This API compares incoming profile or UGC images...||Recognition||09.29.2016|
||The Ableton Live API allows developers to access their entire Live set - including tracks, clips, devices, and hardware control surfaces - programmatically from their third party applications. Using...||Media||09.28.2016|