Backend

Open Library's backend is in a transition period. This page is a short overview of the core systems.

Current Stack

• API direction: We are migrating API endpoints to FastAPI.
• How the local services fit together: See Local Development Architecture for a diagram of the Docker services and their connections.
• Endpoint lookup during migration: Use Endpoints (Transition) for current route/API pointers until FastAPI auto-docs are live.
• Legacy framework: Much of the current app still runs on web.py via Infogami. See Backend General Guide and Understanding the Data Model.
• Caching: We use memcached for performance and hot-path caching.
• Database: We use PostgreSQL 9.3 and are working to migrate to a much newer version; upgrade work is tracked in issue #5675.
• Search: We use Apache Solr for search indexing and query features. See Solr/Search Tech Guide.