Glossary · eUTxO

eUTxO.

Extended UTxO. Cardano’s ledger model: a UTxO can carry datum and be locked by a script, enabling smart contracts on a UTxO chain.

Think of it as

Classic UTxO + a tag and a bouncer. The tag (datum) says what it's for; the bouncer (validator) checks what you present (redeemer) before opening it.

In depth

Extended UTxO (eUTxO) is the model formalised by Chakravarty et al. (2020) and adopted by Cardano. It augments classical UTxOs with a Datum (state attached to the output) and a Validator script (a function that decides whether the output may be spent). Smart contracts gain expressivity while keeping the local-reasoning benefits of UTxO.

Example

A vesting contract is just a UTxO at a script address with a datum like { beneficiary: alice, unlocksAt: 1000 }; a transaction can only spend it when the validator agrees.

Try it interactively Build a complete eUTxO transaction

Next on this path

  1. Datum Custom data attached to an eUTxO. Acts as the “state” of a smart contract output.
  2. Redeemer Data supplied by the spender of an eUTxO. The “action” passed into the validator.
  3. Validator A pure script that gates a UTxO. Returns pass or fail given Datum, Redeemer and Script Context.