user1207: To experiment a little with automatic trading I'm looking for a trading api (like mtgox has) which is used on multiple independent websites so that if one goes under that I then don't have to redo my whole program. If possible one from open source bitcoin trading websites so that I can setup one in a vm and use that to test against.
I'm currently running my tests against Mt.Gox but that can be a bit expensive when the script doesn't perform too well.

user558: goxcli could also be an interesting codebase to make your own multi exchange trading api, goxcli provides an interesting and a shell api you can use as a backend to build your own frontend on top of it. for no goxcli supports only mtgox, but its open source and you can fork it on github : https://github.com/Trasp/GoxCLI
see also : https://github.com/neofutur/bitcoin_simple_php_tools

user117: The Java XChange library could help
It might not be exactly what you're after, but the XChange project provides a demonstration of a general purpose API for communicating with multiple exchanges. 
You could repurpose the code to create your own mock trading endpoints and run up a collection of virtual hosts. In this manner you can test against a reasonably well known set of APIs for the usual failure modes.

1207: <p>To experiment a little with automatic trading I'm looking for a trading api (like mtgox has) which is used on multiple independent websites so that if one goes under that I then don't have to redo my whole program. If possible one from open source bitcoin trading websites so that I can setup one in a vm and use that to test against.</p>

<p>I'm currently running my tests against Mt.Gox but that can be a bit expensive when the script doesn't perform too well.</p>
 558: <p>goxcli could also be an interesting codebase to make your own multi exchange trading api, goxcli provides an interesting and a shell api you can use as a backend to build your own frontend on top of it. for no goxcli supports only mtgox, but its open source and you can fork it on github : <a href="https://github.com/Trasp/GoxCLI" rel="nofollow">https://github.com/Trasp/GoxCLI</a></p>

<p>see also : <a href="https://github.com/neofutur/bitcoin_simple_php_tools" rel="nofollow">https://github.com/neofutur/bitcoin_simple_php_tools</a></p>
 117: <p><strong>The Java <a href="https://github.com/timmolter/XChange" rel="nofollow">XChange library</a> could help</strong></p>

<p>It might not be exactly what you're after, but the XChange project provides a demonstration of a general purpose API for communicating with multiple exchanges. </p>

<p>You could repurpose the code to create your own mock trading endpoints and run up a collection of virtual hosts. In this manner you can test against a reasonably well known set of APIs for the usual failure modes.</p>
