CL about open source craigslist is a big believer in open source software_ and relies on Linux; MySQL, Perl, Apache , Sphinx, Redis Haraka; and many others. craigslist (CL) has released the following open source projects: CL blob service simple HTTP-based, multi-master storage service designed for scale-out and multi- datacenter deployments: multi-master architecture with no single point of failure scales well for both read and write intensive workloads tracks TTLs for automatic expiration and purging of blobs designed for both local and multiple data center replication pluggable index and storage interface (uses SQLite for index and filesystem for storage by default) CL image service large scale image resizing and processing HTTP service: flexible API to choose any quality, size, and center-cropping automatically handles orientation operations from EXIF data stores resized images in the blob service (could use other stores) memcache cluster proxy (MCP) high-performance modular clustering HTTP reverse proxy: high-performance event-driven daemon flexible configuration; easily extensible framework uses standard memcached memory store for caching supports PCRE and rule-based traffic routing by URL, headers and more tracks health of origin servers routes around failures provides configurable URL redirects, rewrites and real-time header transformations addition, craigslist contributes code to the following open source projects: Haraka: added the smtp_client code that helps support pooled connections for proxy queues rewrote all of the smtp proxy and smtp_forward code major contributions to the test suite plugin that does strict DNS checking DNS access control lists contributions to bannering support logging infrastructure changes for more robust logging plugins for aliases_ access lists etc. Redis: