> For the complete documentation index, see [llms.txt](https://quackai.gitbook.io/docs/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://quackai.gitbook.io/docs/architecture-of-autonomy/fordevsandintegrators.md).

# Layer 2: Q402 Execution Fabric

The Q402 Execution Fabric is the transaction backbone of Quack AI’s autonomy architecture. It unifies payments, settlements, and policy enforcement through a single sign-to-pay system.

Q402 is Quack AI’s gasless payment protocol built on EIP-7702 + EIP-712. It allows users and agents to complete any on-chain action — payments, distributions, upgrades, or votes — by signing once, without holding gas tokens or executing manual approvals. Q402 supports any ERC-20 token without requiring token-side upgrades and is currently live across 7 EVM mainnets: Ethereum, BNB Chain, Avalanche C-Chain, X Layer, Mantle, Stable, and Injective EVM.

<figure><img src="/files/6lqWlstC2QcrWwAUl1Sd" alt=""><figcaption></figcaption></figure>

#### How It Works

<table data-header-hidden><thead><tr><th width="80.66668701171875"></th><th></th><th></th><th></th></tr></thead><tbody><tr><td>Step</td><td>Action</td><td>Component</td><td>Output</td></tr><tr><td>1</td><td>User or agent signs an EIP-712 witness + EIP-7702 authorization</td><td>Q402 SDK + Wallet</td><td>Intent, parameters, and delegation defined</td></tr><tr><td>2</td><td>Relayer or facilitator submits transaction</td><td>Q402 Relay Layer</td><td>Gas sponsored and verified</td></tr><tr><td>3</td><td>Policy Engine validates compliance</td><td>Policy Module</td><td>Rule checks and limit enforcement</td></tr><tr><td>4</td><td>On-chain execution settles</td><td>Smart Contracts</td><td>Transfer, payout, or action finalized</td></tr><tr><td>5</td><td>Audit trail recorded</td><td>Q402 Registry</td><td>Signature linked to transaction hash</td></tr></tbody></table>

#### Key Capabilities

* Gasless Transactions — Users or agents can act even with zero native token balance.
* EIP-7702 Delegated Execution — Works with any existing ERC-20 token. No ERC-3009 support, token upgrades, or prior approvals needed.
* Programmable Policies — Limits, expiry, whitelists, and audit hooks built in.
* Facilitator Network — Agents or relayers that pay gas and maintain receipts.
* Verifiable Receipts — Each signature produces a traceable transaction hash for audits.

#### Example Use Cases

| Scenario                       | Outcome                                                  |
| ------------------------------ | -------------------------------------------------------- |
| DAO payouts                    | Distributions settle instantly after governance approval |
| RWA redemptions                | NAV-based withdrawals with audit-proof receipts          |
| Merchant or affiliate payments | One-signature settlements under policy guardrails        |
| Agent-to-agent transactions    | Automated data or API payments between AI systems        |

Q402 turns on-chain execution into a seamless experience — one that combines the simplicity of Web2 payments with the verifiability and decentralization of Web3.