Kooaba-api is a project mainly written in ..., it's free.
Sample code and documentation for kooaba's image recognition APIs.
The kooaba Web Services offer access to kooaba's image recognition platform. The Web Services consist of API's for recognition of query images (Query API) and for uploading reference images to the databases for recognition (Data API).
Access to the API can be obtained via http://www.kooaba.com/en/developers/query_api.
Once you obtained your access keys, documentation on using the API's and some sample code are given in the subdirectories of this project.