DA-03 · Expert

Ducat vaults and transactions

Build and inspect every vault action end to end.

Follow these 10 lessons in order, or choose the topic you need. Each lesson combines an explanation, a worked example and practice inside the Guild.

  1. Open a vault

    The client fetches protocol and oracle data, reserves issuance capacity, builds and signs PSBTs, and submits the request for Guardian validation and co-signing.

    35 minutes · Open lesson
  2. Deposit and withdraw

    Collateral changes consume the current vault UTXO and create a successor while validation enforces allowed value and ratio transitions.

    45 minutes · Open lesson
  3. Borrow and repay

    Issuance or burn activity is paired with a vault state update so UNIT changes reconcile with the vault differential.

    55 minutes · Open lesson
  4. Two-transaction actions

    Open, borrow, and repay use an issue-or-burn transaction plus a vault transaction connected so package structure and fees matter.

    65 minutes · Open lesson
  5. Single-transaction actions

    Deposit, withdraw, repo, and trim update vault state without the separate issuance or burn pattern.

    35 minutes · Open lesson
  6. PSBT manifests and signing inputs

    The client prepares transaction context while signing code derives the precise sighash and Taproot context that each signer must authorize.

    45 minutes · Open lesson
  7. Vault metadata versus enforcement

    OP_RETURN records help reconstruct state, but spend authorization comes from committed Script paths and signatures rather than metadata alone.

    55 minutes · Open lesson
  8. Fees, signature checks, and control blocks

    Ducat estimates transaction weight from inputs, outputs, witnesses, signatures, price commitments, and taptree depth.

    65 minutes · Open lesson
  9. Confirmations and lifecycle state

    Validator and client behavior must read environment-specific confirmation and state rules instead of teaching a timeless hard-coded number.

    35 minutes · Open lesson
  10. CPFP for Ducat transaction pairs

    Package feerate explains how a fee-paying vault child can make a zero-fee issue or burn parent mineable.

    45 minutes · Open lesson