Is there an API that would let me access my AMEX transactions? How do Mint or any other finance websites export my data? If so, is it free?
3 Answers
Take a look at open financial exchange.
American Express appears to support this.

- 13,974
- 3
- 42
- 42
-
2Annoyingly for those of us not living in America it appears that Amex don't support this outside of the US :( – Ash Berlin-Taylor Sep 04 '17 at 20:12
Mint uses the services of Yodlee (see here), a firm that essentially acts as middleware between banks and companies like Mint.
You might be interested in Yodlee's Account Data Gathering API but it looks like it is something that requires a formal agreement, and access to the API probably needs to be paid for..
MasterCard are also looking at releasing an API (see here) so maybe AMEX will follow suit?

- 4,046
- 29
- 41
You can find sample code, SDKs, and a variety of other open source work by American Express on GitHub.
Check the following URL for details description: https://developer.americanexpress.com/essentials
We welcome your contributions on GitHub. Feel free to submit requests or send us a pull request with your contributions. We'd especially like to know which languages you'd like to see more of for our samples repository.

- 7,460
- 17
- 52
- 85
-
3This appears to be aimed at merchant's (i.e. people wanting to accept payments on Amex) not Amex customers directly. – Ash Berlin-Taylor Aug 12 '17 at 15:05