A programmable search engine system is programmable by a variety of different entities, such as client devices and vertical content sites to customize search results for users. Context files store instructions for controlling the operations of the programmable search engine. The context files are processed by various context processors, which use the instructions therein to provide various pre-processing, post-processing, and search engine control operations. Spam related and biased contexts and search results are identified using offline and query time processing stages, and the context files from vertical content providers associated with such spam and biased context and results are excluded from processing on direct user queries.