Glossary term
What is ACID? Meaning for developers
ACID stands for Atomicity, Consistency, Isolation, Durability.
In System Design
Guarantees that transactions are reliable. Example: A bank transfer: both debit and credit happen, or neither.
Learn it properly · System DesignLesson 21: ACID Transactions & Isolation LevelsTwo people book the last seat; a transfer crashes halfway. What ACID really promises, the write-ahead log behind durability, the five anomalies isolation levels do (and don't) prevent, and the practical fixes for real race conditions.In Backend in Depth
Four promises of a database transaction: all or nothing, always valid, separate from other transactions, and safe after a crash.
Learn it properly · Backend in DepthLesson 7: Database Fundamentals for API Engineers: Indexes, Transactions, IsolationB-tree indexes, reading EXPLAIN ANALYZE, transactions and isolation levels, and the race conditions they stop, like selling too many items.