How Git Actually Works Under the Hood

Short summary

Git is fundamentally a content-addressed key-value store using SHA-1 hashing for immutable content identity. Every object—blob (file content), tree (directory), commit (snapshot), and tag—derives its identity from its content, not location, forming a Merkle tree structure where changes cascade upward. This explains why commits are immutable, branches are cheap pointers, history is a directed acyclic graph of snapshots rather than diffs, and rebasing must rewrite hashes.

• •Git's foundation: content-addressed key-value store with SHA-1 hashing and immutable content identity
• •Four object types (blobs, trees, commits, tags) form a Merkle tree where every change cascades upward
• •History is a DAG of snapshots, not diffs—explains immutability, cheap branches, and why rebasing rewrites hashes

Generated with AI, which can make mistakes.