> ## Documentation Index
> Fetch the complete documentation index at: https://trust-link-tsn.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# Cranker Node: Lease, Submit, and Pay Fees

> A Cranker Node leases Mother-Node-verified work, submits the exact authorized transaction, and pays network fees without changing settlement terms.

**In plain English:** A Cranker Node is an independent operator process, not a program. It watches the Receiver for verified work, leases work the Mother Node has authorized, and submits the exact Mother-DNA-authorized transaction to Solana. It pays fees and cannot change amount, recipient, or anything else. Anyone can run one.

## Cranker role

<Note>
  **Status: Live on Devnet.** Anyone can run a Cranker Node against the deployed TSN
  program.
</Note>

A Cranker may:

* lease Node-verified `AUTHORIZED_FUNDING` work
* lease internally-created DNA `SETTLEMENT` work that is already eligible
* submit the exact sender-signed epoch-treasury funding transaction
* submit the exact Mother-DNA settlement transaction supplied by the protocol
* pay Solana fees from its operator wallet
* report transaction signatures and retry safe failures

## Hard boundaries

A Cranker must not:

* decrypt a user's master seed or reconstruct a private commitment key
* choose a different source, recipient, amount, tranche, fee, or change route
* sign as a user, a user authorization, or any Mother-controlled settlement authority
* mark an intent paid, recoverable, or reimbursable by itself
* authorize refunds (Node and Mother only)
* expose Receiver API keys, operator secret keys, or private route material

If a Cranker tampers with any bound field (amount, mint, recipient, commitments, sequence, policy, nullifier, expiry), the Mother-rooted permit breaks and the TSN program rejects the transaction before token movement.

## What the Cranker sees

* Opaque settlement commitment and nullifier
* Public payout coordinates (recipient wallet, mint, amount)
* CrankerVault
* Signed Mother-rooted permit
* Lease id, version, expiry

**Never sees:**

* Encrypted payment binding
* Payment-specific escrow account
* A per-payment PDA (does not exist on the privacy-safe path)
* Sender identity beyond what public payout coordinates require

## Reimbursement

After the Cranker pays the recipient from its CrankerVault, TSN reimburses that exact CrankerVault for the exact amount from the epoch treasury, only if the Mother-rooted permit checks out. Reimbursement is atomic with settlement.

## Prerequisites for running a Cranker

Before starting, the deployment owner must provide:

1. A deployed TSN program ID and matching build / IDL
2. A reachable TSN Receiver with Cranker work endpoints
3. A running or reachable TSN Node that verifies and publishes work
4. The current Receiver Cranker API credential
5. Direct Solana Devnet RPC and WebSocket access
6. A funded operator keypair (dedicated, never an upgrade authority or user wallet)
7. A supported token mint and enough Devnet SOL for fees; a funded CrankerVault if policy requires

The Cranker submits to Solana directly. The TSN RPC Gateway is used by browsers and application services, not as a substitute for the operator's submission RPC.

## Deployment boundary

There is no separate Cranker program to deploy. A Cranker is a signed operator process that uses the already-deployed TSN program. Only the deployment owner should build or upgrade the on-chain program.

## Related

<CardGroup cols={2}>
  <Card title="Mother Node" icon="server" href="/operators/tsn-node">
    The verification and permit-signing role implemented by `tsn-node`.
  </Card>

  <Card title="TSN Layer" icon="network-wired" href="/layers/tsn">
    Program-level settlement, refund, and vault reimbursement.
  </Card>

  <Card title="Architecture" icon="diagram-project" href="/how-it-works/architecture">
    End-to-end sequence diagram.
  </Card>

  <Card title="FAQ" icon="circle-question" href="/get-started/faq">
    What a cranker can and cannot do.
  </Card>
</CardGroup>