Blockchain
Calldata
Raw transaction payload data on an EVM chain — the space where LearnCoin writes Merkle roots as part of the anchor transaction.
Calldata is the data field of an EVM transaction — arbitrary bytes that accompany a transaction payload. For smart-contract calls, calldata encodes the function selector plus arguments. For simple value transfers or data-only transactions, calldata is just the raw bytes.
LearnCoin anchor transactions are data-only: the transaction's calldata contains the 32-byte Merkle root of the credential batch. No smart contract call; no state change on any contract; just a signed transaction whose calldata records the root. This is the cheapest valid way to post data to Base (which is important for economics) and the simplest to verify (any Basescan visitor can decode the calldata as-is).
Post EIP-4844, some L2s moved their bulk data to blob space. LearnCoin's per-credential-batch data is small enough (32 bytes of actual Merkle root) that calldata remains the right target — blobs are for kilobytes, not single hashes.
Related terms