TiDB is an open-source distributed SQL database combining MySQL compatibility with horizontal scalability and HTAP (Hybrid Transactional/Analytical Processing) capabilities. TiDB Cloud Serverless provides free tier (25 GiB storage, 250M RUs) with pay-per-use scaling. Dedicated clusters available for production requirements. The architecture separates computing (TiDB), transactional storage (TiKV), and analytical storage (TiFlash)—enabling both OLTP and OLAP from single database. MySQL 5.7 protocol compatibility ensures existing applications and tools work without modification. TiFlash columnar storage accelerates analytical queries 10-100x compared to row storage. Real-time HTAP enables analytics on live transactional data without ETL delays. Vector search support in development. Best suited for applications outgrowing single MySQL instances needing horizontal scale while maintaining MySQL compatibility. Page should cover: architecture explanation (TiDB, TiKV, TiFlash components), MySQL compatibility level, HTAP use cases and configuration, TiDB Cloud vs self-hosted comparison, pricing analysis, comparison with Aurora and CockroachDB, and migration path from MySQL.