xxx Dropbox API

Create redirect_url
https://dl.dropboxusercontent.com/spa/pjlfdak1tmznswp/powered_by.js/public/index.html

[Dropbox Javascript SDK documentation] (http://dropbox.github.io/dropbox-sdk-js/)
[Dropbox authoriztion workflow] (https://www.dropbox.com/developers/reference/oauth-guide)
[Dropbox API examples] (https://github.com/dropbox/dropbox-sdk-js/blob/master/examples/)
[Dropbox API developer support] (https://www.dropboxforum.com/t5/API-support/bd-p/101000014)

API v2

From API v1 best practices documentation: Rate limiting The API limits the amount of calls your app can make per user. The limits are high enough that any reasonable use of the APIs shouldn't come close to hitting them. Apps that hit the rate limits will receive a 503 error which uses the Retry-After header to indicate exactly when it's okay to start making requests again. If your app uses OAuth 2.0, the error will be a 429 instead. If you keep hitting these limits, contact our developer support team and we'll work with you.

rate limiting on dropbox developer community board

Advice for what to do in case of error 503: The Dropbox API does have a rate limiting system, but we don't have any specific numbers documented. It is only designed to prevent abuse though, and is accordingly very generous. Further, the limits operate on a per-user basis. That being the case, you generally don't need to worry about hitting it in normal use.

Also note that not all 503s indicate rate limiting, but in any case that you get a 429 or 503 the best practice is to retry the request, respecting the Retry-After header if given in the response, or using an exponential back-off, if not.

On using POST in Dropbox API v2