# Calibre OPDS (COPS) COPS (Calibre OPDS PHP Server) serves an existing Calibre ebook library over the web without running Calibre. Point it at the folder containing Calibre's `metadata.db`, and it exposes two things: an OPDS feed that e-reading apps and devices can browse and download from, and a plain HTML catalog for any browser. Search, multiple formats (EPUB, MOBI, PDF, ...), done. The reason it exists is resource frugality. Calibre's own content server drags in the whole Calibre stack; COPS is a small [[PHP]] app that reads the library database directly, so it runs happily on the kind of underpowered, always-on hardware people actually have: a [[Network Attached Storage (NAS)]], a Raspberry Pi, or cheap shared hosting. Any web server with PHP 8.x and the SQLite extensions will do. Originally by Sébastien Lucas (2012-2019), now actively maintained in the mikespub-org fork with modern PHP support. GPL-2.0. On a [[Synology NAS]] there's an even easier path: SynoCommunity packages COPS for DSM, so it installs straight from Package Center (with the SynoCommunity repository added) instead of hand-configuring a web server. Where it fits in the self-hosted library space: COPS ASSUMES Calibre manages your library and only handles serving it, while [[BookOrbit]] manages AND serves its own library with built-in readers and device sync. If you're a long-time Calibre user who just wants OPDS access from [[KOReader]] or a reading app, COPS is the minimal, proven answer. If you're starting from scratch, an all-in-one like BookOrbit covers more. ## References - GitHub (maintained fork): https://github.com/mikespub-org/seblucas-cops - Original project: https://github.com/seblucas/cops - Synology package (SynoCommunity): https://synocommunity.com/package/cops - Setup guide for Synology DSM (Pragmatic Tech Coach): https://ptc-notes.pragmatictechcoach.com/note/Adding-the-COPS-eBook-Library-to-Synology-DSM.html ## Related - [[BookOrbit]] - [[KOReader]] - [[PHP]] - [[Self-hosting]] - [[Network Attached Storage (NAS)]] - [[Synology NAS]]