> ## Documentation Index
> Fetch the complete documentation index at: https://docs.cashmere.exchange/llms.txt
> Use this file to discover all available pages before exploring further.

# System Design

> Architecture of the CashmereLabs Autonomous Monetary Infrastructure.

## Architectural Summary

CashmereLabs operates a dual-layer architecture that combines:

* **On-chain execution** written in Solidity, Move, and Anchor to govern burn, attestation, mint, yield routing, and policy enforcement.
* **Autonomous relayers** implemented in Go that handle pricing, attestation retrieval, compliance, and settlement orchestration across EVM and non-EVM networks.

Together, these layers deliver deterministic, zero-slippage mobility for stablecoins while powering autonomous yield, privacy-preserving settlement, and fiat ↔ crypto connectivity.

## On-Chain Components

### CashmereCCTP (EVM)

* Verifies relayer-signed fee quotes (ECDSA).
* Executes burns, emits verifiable events, and enforces minimum output guarantees.
* Supports `transfer`, `transferV2`, and permit variants for gas-optimised execution.

### Move / Anchor Modules (Sui, Aptos, Solana)

* Mirror the burn → attest → mint lifecycle using Ed25519 signature schemes.
* Integrate chain-native fee handling and deterministic finality.

### Smart Account Infrastructure (ERC-4337)

Built on ERC-4337 account abstraction with specialised validator modules:

* **Smart Accounts:** Users interact via programmable, non-custodial accounts.
* **Validator Modules:** Authenticate relayer/yield-agent actions under cryptographic policies.
* **Session Keys:** Grant scoped authority for bridging, yield allocation, or ramp transfers without exposing primary keys.
* **Programmable Policies:** Enterprises define limits (e.g., max transfer size, approved protocols, scheduling windows).

This transforms static wallets into autonomous smart accounts—enabling safe delegation to agents while users retain full asset control.

## Cross-Chain Execution Model

| Layer                     | Description                                                                                  |
| ------------------------- | -------------------------------------------------------------------------------------------- |
| **EVM Chains**            | CashmereCCTP contracts handle native burn-and-mint execution with on-chain fee verification. |
| **Non-EVM Chains**        | Move/Anchor modules and SDKs coordinate attestation-based mints with relayer support.        |
| **Unified Policy Engine** | Enforces compliance, minimum output guarantees, and routing rules on every transaction.      |

## Autonomous Relayers

Relayers are stateless orchestration agents. They never custody user funds; instead they validate events, quote fees, and submit destination transactions.

### Runtime Capabilities

* Subscribe to burn events across supported chains.
* Estimate fees using issuer feeds, on-chain gas data, and Cashmere policy limits.
* Sign quotes (ECDSA/Ed25519) with ≈100-second expiries.
* Retrieve and verify attestations from Circle CCTP, Tether USDT0, and future issuers.
* Submit destination mints with nonce management and retry logic.
* Enforce per-chain policy hooks (allowlist/denylist, AML checks).
* Provide observability via Prometheus metrics, structured logging, and circuit breakers.

## Execution Flow

1. **Detect Burn** – listen for `CashmereTransfer` (or equivalent) events on the origin chain.
2. **Retrieve Attestation** – fetch issuer proofs and validate signatures.
3. **Mint & Finalise** – submit the destination mint, enforcing min finality thresholds (1,000 Fast / 2,000 Normal).
4. **Record & Monitor** – persist transaction data and expose it through the Monitoring API for analytics.

## Fee Quotation Pipeline

* Clients call `GET /getEcdsaSig_native` or `GET /getEd25519Sig_native`.
* Relayers compute destination gas, issuer cost, and policy-defined overhead.
* Response includes `fee`, `deadline`, and signature.
* Users embed these values when invoking on-chain contracts.
* Quotes expire after \~100 seconds to keep pricing aligned with live network conditions.

## Yield Agent Layer

On top of the transfer infrastructure, Cashmere deploys autonomous agents that turn idle stablecoins into self-optimising capital:

* Continuous monitoring of APRs across integrated venues (Morpho, Euler, Jupiter).
* Policy-driven allocation using user-approved session keys (no custody risk).
* Cross-chain rebalancing via the same zero-slippage transfer fabric.
* Transparent reporting and withdrawal optionality at all times.

## Privacy & Compliance Layer

The forthcoming Cashmere Privacy module introduces zk-based settlement with optional selective disclosure:

* Confidential transfers for users and DAOs.
* Audit trails and disclosure hooks for regulated institutions.
* Integration with policy engines to maintain KYC/AML compatibility.

## Reliability & Security

| Mechanism                        | Purpose                                                                         |
| -------------------------------- | ------------------------------------------------------------------------------- |
| **Trust minimisation**           | Cashmere never holds user funds; all mints/burns occur via issuer contracts.    |
| **Deterministic outputs**        | Guaranteed minimum amounts remove MEV and sandwich risk.                        |
| **Infrastructure hardening**     | Dockerised, load-balanced relayers with automated failover and throttling.      |
| **Policy controls**              | Allowlist/denylist, rate limits, and compliance hooks per chain.                |
| **Non-custodial smart accounts** | Automation executes via user-controlled accounts with programmable permissions. |

For detailed contract interfaces and APIs, see [Smart Contracts](/developers/smart-contracts) and [Backend APIs](/developers/backend-apis).