State Compression

State Compression is Solana's technique for storing the cryptographic fingerprint (root hash) of a Merkle tree on-chain while keeping the actual leaf data off-chain in the Solana ledger's account data logs, reducing the cost of storing large datasets by orders of magnitude. A compressed NFT collection of 1 million items costs roughly 50 SOL to mint versus ~12,000 SOL with standard SPL accounts, because only a single Concurrent Merkle Tree account occupies on-chain storage. Any data change requires updating the root hash and supplying a Merkle proof to the on-chain program, which verifies inclusion without reading the full dataset.