Deploying Contracts

The ScalusBlueprintPlugin provides a deploy sbt task that creates a reference script UTxO from a Contract object. It extracts the compiled script, attaches it to a new UTxO, builds and signs the transaction, and submits it via Blockfrost.

Setup

project/plugins.sbt:


addSbtPlugin("org.scalus" % "scalus-sbt-plugin" % "<scalus-version>")

build.sbt:


lazy val myProject = (project in file("."))
    .enablePlugins(ScalusBlueprintPlugin)
    .settings(
      scalaVersion := "3.3.7",
      addCompilerPlugin("org.scalus" % "scalus-plugin" % "<scalus-version>" cross CrossVersion.full),
      libraryDependencies ++= Seq(
        "org.scalus" %% "scalus" % "<scalus-version>",
        "org.scalus" %% "scalus-cardano-ledger" % "<scalus-version>",
      ),
    )

Define a Contract object with a compiled validator and blueprint:


@Compile
object MyValidator extends Validator {
    inline override def spend(
        datum: Option[Data], redeemer: Data, tx: TxInfo, ownRef: TxOutRef
    ): Unit = {
        val owner = datum.getOrFail("No datum").to[PubKeyHash]
        require(tx.signatories.contains(owner), "Not signed by owner")
    }
}
 
object MyContract extends Contract {
    private given Options = Options.release
    lazy val compiled = PlutusV3.compile(MyValidator.validate)
    lazy val blueprint = Blueprint.plutusV3[PubKeyHash, Unit](
      title = "My Validator",
      description = "Owner-signed spending validator",
      version = "1.0.0",
      license = None,
      compiled = compiled
    )
}

Usage


sbt "deploy MyContract --network preprod --blockfrost-key <key> --mnemonic '<24 words>' --address <bech32-address>"

The first argument is the simple name of your Contract object. Named flags:

Flag	Env Variable	Default	Description
`--network`	`CARDANO_NETWORK`	`preview`	`preview`, `preprod`, or `mainnet`
`--blockfrost-key`	`BLOCKFROST_API_KEY`	—	Blockfrost API key
`--mnemonic`	`CARDANO_MNEMONIC`	—	BIP-39 mnemonic phrase
`--address`	—	—	Bech32 address for the reference script UTXO

CLI flags take precedence over environment variables. Using env vars avoids secrets in shell history:


export BLOCKFROST_API_KEY=preprodXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
export CARDANO_MNEMONIC="word1 word2 ... word24"
export CARDANO_NETWORK=preprod
 
sbt "deploy MyContract --address addr_test1q..."

Example output:


[info] Deploying contract 'MyContract' to preprod...
[info] Tx e484fdac... submitted successfully
[info] Deployed successfully! Transaction hash: e484fdac...

What’s Next?

Blueprint Generation — Produce and verify CIP-57 blueprints alongside deployment
Working with Contract — Reference the deployed script from off-chain dapp code
Building Transactions — Spend from your reference script with TxBuilder