Deposit a script UTxO

This example deposits an output while preserving its script address and datum inside the head. It uses an always-succeeding script on preprod only; anyone can spend funds locked by this example script. For application-specific checks, see deposit from a dApp.

Prerequisites

Complete the testnet tutorial through opening a head. Keep that node running with fuel available. Use the same working directory, Alice's funded wallet, cardano-cli, jq, and curl.

export CARDANO_NODE_SOCKET_PATH="$PWD/node.socket"
export CARDANO_NODE_NETWORK_ID=1
export HYDRA_API=http://127.0.0.1:4001
WALLET_ADDR=$(cat credentials/alice-funds.addr)
cardano-cli query protocol-parameters --out-file l1-protocol-parameters.json

Create and fund the script output

Save this script as always-true.plutus:

{
  "type": "PlutusScriptV2",
  "description": "Always succeeds: test funds only",
  "cborHex": "49480100002221200101"
}

Create its address and select an ADA-only funding input with enough value for the 10 ADA output, transaction fees, and change:

cardano-cli address build \
  --payment-script-file always-true.plutus \
  --testnet-magic 1 --out-file script.addr
SCRIPT_ADDR=$(cat script.addr)
cardano-cli query utxo --address "$WALLET_ADDR" --out-file wallet-utxo.json
FUNDING_INPUT=$(jq -er 'to_entries | map(select((.value.value | keys) == ["lovelace"] and .value.value.lovelace >= 15000000)) | .[0].key // error("Need at least 15 ADA")' wallet-utxo.json)

cardano-cli conway transaction build \
  --tx-in "$FUNDING_INPUT" \
  --tx-out "$SCRIPT_ADDR+10000000" \
  --tx-out-inline-datum-value 42 \
  --change-address "$WALLET_ADDR" \
  --out-file lock.json
cardano-cli conway transaction sign \
  --tx-file lock.json \
  --signing-key-file credentials/alice-funds.sk \
  --out-file lock-signed.json
cardano-cli conway transaction submit --tx-file lock-signed.json
LOCK_TX_ID=$(cardano-cli conway transaction txid --tx-file lock-signed.json | jq -er .txhash)

Wait until the following query returns the script output. Selecting its exact reference avoids accidentally using another person's output at this shared script address.

SCRIPT_INPUT="$LOCK_TX_ID#0"
cardano-cli query utxo --tx-in "$SCRIPT_INPUT" --out-file script-utxo.json
jq -e --arg input "$SCRIPT_INPUT" 'has($input)' script-utxo.json

Prepare the blueprint

The blueprint includes the script witness, datum reference, redeemer, and an execution budget. It has no outputs, so the node records the supplied UTxO with its existing address, value, datum, and reference.

cardano-cli conway transaction build-raw \
  --tx-in "$SCRIPT_INPUT" \
  --tx-in-script-file always-true.plutus \
  --tx-in-inline-datum-present \
  --tx-in-redeemer-value 42 \
  --tx-in-execution-units '(1000000, 100000)' \
  --protocol-params-file l1-protocol-parameters.json \
  --fee 0 \
  --out-file script-blueprint.json

jq -n \
  --slurpfile blueprint script-blueprint.json \
  --slurpfile utxo script-utxo.json \
  '{blueprintTx: $blueprint[0], utxo: $utxo[0]}' \
  > script-commit-request.json

build-raw constructs a transaction; it does not evaluate its scripts. The node evaluates and balances the actual deposit transaction. For a different script, supply its required datum, redeemer, signers, reference inputs, and input context. Use explicit blueprint outputs when supplying reference-input context, because a blueprint without outputs deposits the entire supplied UTxO map. Even an always-succeeding script consumes execution resources.

If you supply explicit blueprint outputs, those outputs define ownership on L2. Paying them to a key address releases them from the script. Do not include reference scripts in the deposited outputs: the node cannot reconstruct them from the deposit encoding. Publish them separately on L2 if needed.

Submit the deposit

Open a WebSocket connection before submitting to observe the lifecycle:

websocat 'ws://127.0.0.1:4001?history=no'

In the original terminal, request the draft and add any client witness while preserving the node's existing witness:

curl --fail-with-body -sS "$HYDRA_API/commit" \
  -H 'Content-Type: application/json' \
  --data-binary @script-commit-request.json \
  > script-deposit.json
cardano-cli conway transaction sign \
  --tx-file script-deposit.json \
  --signing-key-file credentials/alice-funds.sk \
  --out-file script-deposit-signed.json
cardano-cli conway transaction submit --tx-file script-deposit-signed.json

Wait for CommitFinalized, then inspect GET /snapshot/utxo. The deposited output should still have the script address and datum 42. Submission and CommitRecorded precede activation and settlement; they do not make the output spendable on L2. See deposit timing and recovery.

Prerequisites​

Create and fund the script output​

Prepare the blueprint​

Submit the deposit​

Prerequisites

Create and fund the script output

Prepare the blueprint

Submit the deposit