it looks like another free native API is biting the dust.  Joining the trend from Xing, and Facebook image sharing website 500px is shutting down its API.

Letter from 500px

Shutting down API access

In January, we removed public access to our API. 500px has always fostered creativity with technology, but due to shifting business priorities, we’ve now decided to shut down the API completely. This decision is part of a larger strategic shift—focusing our energy on continuing to build the world’s best photography community at, as well as strengthening our asset protection and improving our site’s performance.

As of June 15, we’ll be shutting down all access to the API, which means you will no longer be able to use it to pull images or data.

We will consider the possibility of creating our own API for 500px.