ERC-721A and Compressed NFTs

The NFT Gas Problem

The original NFT standard (ERC-721) was elegant but inefficient. Minting 10,000 NFTs in a single collection meant ~10,000 separate storage operations — gas costs in the thousands of dollars for the collection deployer and end users alike. During the 2021 NFT boom, gas wars where mints would cost $200-500 in fees per NFT became a major friction point. Standards evolved to solve this in two distinct ways: ERC-721A for cheaper Ethereum mints, and Solana state compression for radically different storage architecture.

ERC-721A — Batch-Minting Optimisation

ERC-721A, introduced by Azuki's team in early 2022, is a backwards-compatible reimplementation of ERC-721. The key insight: instead of recording each minted NFT's owner separately, ERC-721A records ownership for ranges of consecutive token IDs. When Alice mints tokens 1-5 in one transaction, only one ownership record is created. The downside: transferring token 3 later requires checking which range it falls in. The net effect: mint gas drops dramatically; transfer gas slightly increases. For most collections this is the right trade because mints are once-per-token, transfers are usually rare.

Compressed NFTs — Solana's Approach

Solana's state compression goes much further. Instead of storing each NFT's metadata on-chain, compressed NFTs (cNFTs) store all the data in a Merkle tree off-chain, with only the root hash on-chain. Owners can prove they own a specific NFT by providing the Merkle proof. The cost of minting 1 million cNFTs is roughly the cost of minting 1 regular NFT on Ethereum. This enables use cases (loyalty programs, in-game items, ticketing) that wouldn't be economically viable with traditional NFT storage.

• ERC-721A: batch-minting gas optimisation, backwards-compatible with ERC-721
• cNFTs: Solana's compressed NFTs store data off-chain in Merkle trees
• ERC-721A: better mints, slightly worse transfers
• cNFTs: dramatically cheaper for high-volume use cases