Does anyone know if there's a Gatherer API?

I'm working on web-based platform for judges and judge candidates, and it would really help if I could get stuff easily from gatherer.
I'm looking for stuff like card images, Oracle text, mana costs, format legality and so on…

Thanks!

I'm doing some work right now using mtgjson.com's stuff. It used to have an image library as well, but that was C&D'd. Otherwise, I'd recommend doing some investigation in that system, as you may still be able to leverage Gatherer for some of that data from within that system.

There are no official APIs that I am aware of, although there are a few unofficial ones that emulate such. (Simply google “Gatherer API” to find a few already prepared options). As Jordan suggested, images will need to come directly from Gatherer itself due to the more… aggressive legal stance toward any outside hosting, but it would be trivial to generate a simple file that could parse through each card's HTML page, grab the image URL, and simply link to the direct gatherer resource (there's likely an easier way or format in each image's URL that would make this very easy). There are no guarantees, however, that this won't be treated identically as any other image resource.

You may want to refer to Sections 2a & 2b in http://gatherer.wizards.com/pages/content.aspx?x=mtg/gatherer/termsofuse

I'm no lawyer, but that would give me some pause before embarking on a project

magiccards.info doesn’t have an API per se but I think you can add their
search bar to your site… probably not exactly what you were looking for but
super easy to implement.

http://magiccards.info/about.html

There's no official Gatherer API, sadly. MTGJson is good, and I'd also like to recommend deckbrew. It's a very easy to use REST API.

A couple of example requests:

http://api.deckbrew.com/mtg/cards?name=Tarmogoyf
http://api.deckbrew.com/mtg/sets

You get the idea.