Glossary · Smart Contracts

Inline datum.

A datum stored directly inside the UTxO it belongs to, instead of as a hash that the spender has to resolve.

Think of it as

The note pinned to the box is now glued to the lid, not folded in someone's wallet. Anyone who finds the box can read it directly.

In depth

Before Plutus V2 (Babbage hard fork, 2022), a UTxO at a script address only stored the hash of its datum, the spender had to provide the actual datum bytes in the witness set, matching the hash. CIP-32 added inline datums: the full datum value can be stored on-chain in the output itself, removing the off-chain round-trip and making concurrent UTxO consumption easier.

Example

A DEX pool stores its current reserves as an inline datum on the pool UTxO. Anyone can read it without having to fetch the matching datum from somewhere else.

Next on this path

  1. Reference script A script body stored on-chain in a UTxO so transactions can use it by reference instead of bundling the whole script every time.
  2. Reference input A UTxO the transaction can read but not spend. Used to look at on-chain data (or a script) without consuming it.