Read the Docs is a Django-based web application for building, hosting, and serving documentation from version control repositories (GitHub, GitLab, Bitbucket). It supports Sphinx, MkDocs, and other documentation generators, with automated builds triggered by webhooks, versioning (semver, calver, custom), custom domains, subprojects, translations, and a full-text search powered by Elasticsearch. The platform includes a multi-tenant organization system with teams, invitations, and Stripe-based subscriptions for commercial features like concurrent builds and private documentation. Architecturally, it is a monolithic Django application with multiple apps (projects, builds, search, analytics, oauth, embed, proxito, etc.) communicating via Celery task queues for async operations (builds, indexing, email). It exposes REST APIs (v2 and v3) for programmatic access, and serves documentation through a custom proxito middleware that handles domain resolution, caching, redirects, and CDN integration. The codebase demonstrates strong engineering practices with extensive use of mixins, class overrides via SettingsOverrideObject, structured logging with structlog, and a comprehensive test suite. Key features include OAuth-based repository synchronization, automation rules for version management, an embed API for content fragments, file tree diff for pull request previews, audit logging, and spam detection. The system is designed for extensibility, with many components replaceable through Django settings, and relies on external services like AWS S3 for storage, Elasticsearch for search, and Stripe for payments.