Is anyone there?

The CREST API has a fistful of endpoints available to 3rd party developers. Interestingly, sending a request to the root endpoint returns a JSON string of all available endpoints; pretty handy.

https://public-crest.eveonline.com/

Most browsers will return this object as a download as there is no filetype associated with the response. When sent through an application however, the string can be read as normal. This stuff is pretty straight forward as all that needs doing is identifying the desired endpoint, some examples are outlined below.

https://public-crest.eveonline.com/market/10000002/types/34/history/

Will return the history of the item ID 34 (Tritanium) from a market region ID 10000002 (The Forge).

https://public-crest.eveonline.com/market/10000002/orders/sell/?type=34/

Will return all current sell orders of the item ID 34 (Tritanium) from a market region ID 10000002 (The Forge).

More information can be found on the EVE Online wiki.

Anything else?

The CREST API is still being implemented so a lot of the endpoints do not work, but in future it is planned to give access to any public game data from characters, industry, market, corporations and alliances. There are also plans for an authentication only (OAuth) API for account private account data.

Rate Limits

Rate Per Second: 150
Burst Size: 400
Maximum concurrent connections: 20

For your requests, this means you can send an occasional burst of 400 requests all at once. If you do, you'll hit the rate limit once you try to send your 401st request unless you wait.

Your bucket refills at a rate of 1 per 1/150th of a second. If you send 400 requests at once, you need to wait 2.67 seconds before you can send another 400 requests (1/150 * 400), if you only wait 1.33 seconds you can send another 200, and so on. Altrnatively, you can send a constant 150 requests every 1 second.