
File Sharing and Storage.
Dropbox API is a free Cloud Storage & File Sharing API that requires OAuth authentication, is served over HTTPS and has unconfirmed CORS support.
With the DBX Platform, you can go from idea to implementation quickly and easily. Discover how you can develop apps for millions of Dropbox users.
Details from dropbox.com.

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Geocode an address, validate an email, track a flight or pull stock data with one account, one dashboard and one API key.
Super simple file sharing, convenient, anonymous and secure
The Dropbox API is provided by Dropbox (dropbox.com). With the DBX Platform, you can go from idea to implementation quickly and easily. Discover how you can develop apps for millions of Dropbox users.
Yes. The Dropbox API is listed in the Cloud Storage & File Sharing category of the public-apis directory, which only includes APIs that are free or have a free tier. Check its documentation for rate limits and paid plans.
Yes. The Dropbox API uses OAuth authentication, so you need to register for credentials before making requests.
CORS support for the Dropbox API is unknown. Test a request from the browser, and fall back to a server-side call if it is blocked.
Yes. The Dropbox API is served over HTTPS, so it's safe to use in production.