# Vault

The **KRNL Vault** is the economic backbone of the protocol — the component that ensures workflows not only execute securely but also settle fairly. Executors may compute, attestors may prove, but the Vault handles the **money flows**: billing, fee collection, storage, and distribution.

By integrating with Ethereum standards like **EIP-7702** (delegated accounts) and **EIP-4337** (account abstraction), the Vault makes billing seamless, flexible, and fully automated. This ensures developers can focus on building while the protocol transparently handles value exchange.

### Role in the Protocol

* **Billing Engine** – Enforces payment flows for every workflow execution.
* **Fee Collector** – Captures protocol fees, gas fees, and service costs.
* **Distributor** – Routes funds to node operators, executor builders, kernel providers, and the protocol treasury.
* **Economic Guardian** – Prevents underpayment, double-spending, and ensures sustainability via transparent fee policies.

### Billing System with EIP-7702 + EIP-4337

The Vault leverages Ethereum’s most advanced account standards to handle payments:

#### **EIP-7702: Delegated Accounts**

* Lets an **EOA (Externally Owned Account)** delegate authority to a **Smart Contract Account (SCA)**.
* SCAs can sign and pay for workflow executions on behalf of the user.
* Supports **dual transactions**:
  1. The **workflow execution** itself.
  2. The **corresponding payment** into the Vault.
* Benefits:
  * Users don’t have to manually juggle fee payments.
  * Developers can enforce billing policies at the account level.

#### **EIP-4337: Account Abstraction**

* SCAs function as **programmable wallets**, enabling meta-transactions.
* Supports:
  * **Bundlers**, who relay batched transactions into the chain.
  * **Paymasters**, who can sponsor gas fees for users.
* Benefits:
  * Smooth UX: users don’t need ETH for gas.
  * Flexible billing: fees can be paid in stablecoins or other ERC-20s.
  * Gas optimization: multiple workflow steps can be batched into a single transaction.

Together, **7702 + 4337 turn KRNL billing into a self-contained system**: users delegate, SCAs enforce, Vault collects, and everything is cryptographically verifiable.

### Fee Structure

Every workflow execution incurs three categories of cost:

**Total Execution Cost = Platform Base Fee + External Service Costs + Gas Costs**

1. **Platform Base Fee**
   * Paid to the Vault for using KRNL infrastructure.
   * Funds node operators, executor builders, and protocol maintenance.
2. **External Service Costs**
   * APIs, off-chain data providers, and kernel services each have their own costs.
   * Automatically collected and routed to the correct provider.
   * Enables long-tail API providers to monetize directly within KRNL.
3. **Gas Costs**
   * Native Ethereum gas fees for on-chain verification and settlement.
   * Can be sponsored by developers (via Paymasters) or paid directly by users.

### Distribution of Fees

The Vault executes **automated, rules-based distribution**:

* **Node Operators** – Paid for running KRNL-Nodes that execute workflows and provide computational resources.
* **Executor Builders** – Receive rewards when their executors are used inside workflows.
* **Protocol Treasury** – Funds governance, ecosystem incentives, audits, and long-term development.

This ensures that every contributor to the ecosystem is rewarded **fairly and transparently**.