# Overview

## Introduction

MAP Protocol is a peer-to-peer cross-chain infrastructure enabling secure interoperability between heterogeneous blockchains. The architecture is built on a three-layer design that separates concerns and provides flexibility.

## Three-Layer Architecture

```
┌─────────────────────────────────────────────────────────────────────────┐
│                        Application Layer                                 │
│                                                                          │
│    Cross-chain DApps    │    Bridges    │    Omnichain Services         │
└─────────────────────────────────────────────────────────────────────────┘
                                    │
                                    ▼
┌─────────────────────────────────────────────────────────────────────────┐
│                     MOS (MAP Omnichain Service) Layer                    │
│                                                                          │
│    Message Passing    │    Asset Transfer    │    Verification          │
└─────────────────────────────────────────────────────────────────────────┘
                                    │
                                    ▼
┌─────────────────────────────────────────────────────────────────────────┐
│                         Protocol Layer                                   │
│                                                                          │
│    MAP Relay Chain    │    Light Clients / TSS    │    Maintainers      │
└─────────────────────────────────────────────────────────────────────────┘
```

### Layer 1: Protocol Layer

The foundation providing core cross-chain verification and consensus.

| Component       | Function                                           |
| --------------- | -------------------------------------------------- |
| MAP Relay Chain | Central relay hub and verification center          |
| Light Clients   | On-chain verification of other chains (v1)         |
| TSS Network     | Threshold signature for decentralized custody (v2) |
| Maintainers     | Network participants maintaining cross-chain state |

### Layer 2: MOS Layer

The service layer providing cross-chain capabilities to applications.

| Component         | Function                                |
| ----------------- | --------------------------------------- |
| Message Protocol  | Standardized cross-chain message format |
| Messenger/Relayer | Off-chain services delivering messages  |
| Vault/Gateway     | Asset custody and verification          |

### Layer 3: Application Layer

Where developers build omnichain applications.

**Examples:**

* Cross-chain DEX
* Omnichain NFT platforms
* Multi-chain lending protocols
* Cross-chain governance

## MAP Relay Chain

MAP Relay Chain (Atlas) is an EVM-compatible blockchain at the core of the protocol.

### Key Features

| Feature       | Description                                    |
| ------------- | ---------------------------------------------- |
| Consensus     | Istanbul BFT with \~5 second blocks            |
| Compatibility | Fully EVM compatible                           |
| Native Token  | MAPO for gas and staking                       |
| Finality      | Instant finality with 2/3+ validator agreement |

### Functions

1. **Relay Hub**: Routes cross-chain messages
2. **Verification Center**: Hosts light clients and TSS contracts
3. **Governance**: Manages validators and protocol parameters

## Two Cross-Chain Solutions

MAP Protocol offers two complementary solutions:

### v1: Light Client Solution

Uses on-chain light clients for trustless verification.

```
Source Chain → Light Client → MAP Relay Chain → Light Client → Target Chain
```

**Best for:**

* Maximum trustlessness
* EVM-to-EVM communication
* Message passing

[Learn more about v1](https://docs.mapprotocol.io/learn/architecture/v1-light-client)

### v2: TSS Solution

Uses threshold signatures for decentralized custody.

```
Source Chain → Vault → Maintainer Network (TSS) → Gateway → Target Chain
```

**Best for:**

* Bitcoin integration
* Fast asset transfers
* Lower gas costs

[Learn more about v2](https://docs.mapprotocol.io/learn/architecture/v2-tss)

## Network Participants

| Role             | Responsibility                                       |
| ---------------- | ---------------------------------------------------- |
| **Validators**   | Produce blocks on MAP Relay Chain                    |
| **Maintainers**  | Update light clients (v1) or participate in TSS (v2) |
| **Messengers**   | Relay cross-chain messages (v1)                      |
| **Relayers**     | Submit signatures to target chains (v2)              |
| **LP Providers** | Provide liquidity to Vaults (v2)                     |

## Supported Chains

MAP Protocol supports various blockchain types:

| Chain Type | Examples               | v1 Support | v2 Support |
| ---------- | ---------------------- | ---------- | ---------- |
| EVM        | Ethereum, BSC, Polygon | ✅          | ✅          |
| Non-EVM    | Near, Solana           | ✅          | ✅          |
| Bitcoin    | BTC                    | ❌          | ✅          |

## Security Model

### Decentralization

* No single point of failure
* Distributed validation and signing
* Permissionless participation (v1) or staked participation (v2)

### Cryptographic Security

* Light client proofs based on source chain consensus
* TSS threshold signatures with 2/3 fault tolerance
* On-chain verification

### Economic Security

* Staking requirements
* Slashing for misbehavior
* Incentive alignment

## Getting Started

Depending on your role:

| Role       | Getting Started                                                                |
| ---------- | ------------------------------------------------------------------------------ |
| User       | Use cross-chain bridges built on MAP Protocol                                  |
| Developer  | [Build cross-chain apps](https://docs.mapprotocol.io/develop/overview)         |
| Validator  | [Run a validator node](https://docs.mapprotocol.io/validator/become-validator) |
| Maintainer | [Run Compass-TSS](https://docs.mapprotocol.io/compass-tss-crossx/overview)     |