App Transport Security(ATS)

Client <-http-> Server
Get in touch with the people running the server

Web Services and API
client(app) HTTP server

Flicker API document
https://www.flickr.com/services/api/

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https://api.flicker.com/services/rest/?method=*&api_key=*&text=*&extras=url_m

some of API
OpenMenu API, World Bank API, Sunlight API, Gilt API, Riot GAmes API

To use an API:
1. Sign up for an account with the service
2. Register the app
3. [Usually] source authentication process