XDC Network Architecture¶

This document explains the technical architecture of XDC Network, including its hybrid design, consensus mechanism, and key components.

Overview¶

XDC Network is an enterprise-grade hybrid blockchain that combines:

Public Network: Open, permissionless mainnet
Private Subnets: Permissioned networks for enterprises
Interoperability: Cross-chain communication between networks

flowchart TB
    subgraph "XDC Ecosystem"
        subgraph "Public Layer"
            A[XDC Mainnet]
            B[108 Masternodes]
        end

        subgraph "Private Layer"
            C[Enterprise Subnet 1]
            D[Enterprise Subnet 2]
        end

        subgraph "Bridge Layer"
            E[XDC Zero]
            F[Checkpoint Contract]
        end
    end

    B --> A
    C --> F
    D --> F
    F --> A
    E --> A
    E --> C
    E --> D

Network Layers¶

Layer 1: XDC Mainnet¶

The public XDC mainnet is the foundation:

Component	Description
Chain ID	50 (Mainnet), 51 (Apothem Testnet)
Consensus	XDPoS 2.0
Block Time	~2 seconds
Validators	108 Masternodes
EVM Version	Shanghai (latest)

Layer 2: Private Subnets¶

Enterprise-specific chains with:

Custom consensus parameters
Permissioned access
Data privacy
Mainnet checkpointing

Bridge Layer¶

XDC Zero: Cross-chain asset transfers
Checkpoint Contract: Subnet state anchoring

Consensus: XDPoS 2.0¶

XDC uses XinFin Delegated Proof of Stake (XDPoS) version 2.0:

How It Works¶

Token Holders stake XDC to vote for Masternode candidates
Top 108 Candidates become active Masternodes
Masternodes take turns proposing blocks (round-robin)
Validators sign blocks to confirm
Rewards distributed to Masternodes and voters

Key Features¶

flowchart LR
    A[XDPoS 2.0] --> B[BFT Finality]
    A --> C[Forensic Monitoring]
    A --> D[Penalty Mechanism]

    B --> E[Instant Finality]
    C --> F[Detect Misbehavior]
    D --> G[Slash Bad Actors]

Feature	Description
BFT Finality	Byzantine Fault Tolerant consensus for instant finality
Forensic Monitoring	Detects and records malicious validator behavior
Slashing	Penalties for misbehaving validators
Epoch System	900-block epochs for validator rotation

Validator Requirements¶

Requirement	Mainnet	Testnet
Minimum Stake	10,000,000 XDC	10,000 XDC
Hardware	16GB RAM, 500GB SSD	8GB RAM, 100GB SSD
Bandwidth	100 Mbps	50 Mbps
Uptime	99.9%+ expected	-

Node Types¶

Masternode (Validator)¶

Proposes and validates blocks
Requires 10M XDC stake
Earns block rewards

Standby Node¶

Ready to become Masternode
Maintains full chain state
Can be promoted if Masternode fails

Full Node¶

Stores complete blockchain
Serves RPC requests
No staking required

Archive Node¶

Stores all historical states
Required for block explorers
Higher storage requirements

EVM Compatibility¶

XDC is fully Ethereum Virtual Machine (EVM) compatible:

Supported Tools¶

Category	Tools
Languages	Solidity, Vyper
Frameworks	Hardhat, Truffle, Foundry
Libraries	Web3.js, Ethers.js, xdc3.js
Wallets	MetaMask, XDCPay
IDEs	Remix, VS Code

Migration from Ethereum¶

// Ethereum code works on XDC with minimal changes

// Change 1: RPC endpoint
const web3 = new Web3('https://rpc.xinfin.network'); // XDC mainnet

// Change 2: Address format (optional)
// Ethereum: 0x71C765...
// XDC:      xdc71C765... (just prefix change)

// Everything else works the same!
const contract = new web3.eth.Contract(ABI, address);

Transaction Lifecycle¶

sequenceDiagram
    participant User
    participant Node
    participant Mempool
    participant Validator
    participant Network

    User->>Node: Submit Transaction
    Node->>Node: Validate Tx
    Node->>Mempool: Add to Mempool
    Validator->>Mempool: Select Transactions
    Validator->>Validator: Create Block
    Validator->>Network: Propose Block
    Network->>Network: Validate & Sign
    Network->>User: Transaction Confirmed (~2s)

Transaction Finality¶

Stage	Time	Description
Submitted	0s	Tx sent to node
Pending	0-2s	In mempool, awaiting inclusion
Included	2s	In a block
Final	2-4s	BFT finality achieved

Smart Contract Execution¶

Gas Model¶

XDC uses a gas model similar to Ethereum:

Transaction Cost = Gas Used × Gas Price

Example:
- Simple transfer: 21,000 gas
- Gas price: 0.25 Gwei
- Cost: 21,000 × 0.25 Gwei = 5,250 Gwei ≈ $0.00004

Contract Limits¶

Parameter	Value
Block Gas Limit	420,000,000
Max Contract Size	24 KB
Max Call Depth	1024

Security Model¶

Network Security¶

108 Validators: Distributed consensus
10M XDC Stake: Economic security
Slashing: Penalties for misbehavior
Forensic Monitoring: Behavior tracking

Cryptography¶

Signing: ECDSA (secp256k1)
Hashing: Keccak-256
Addresses: 20-byte derived from public key

Network Parameters¶

Mainnet¶

Parameter	Value
Chain ID	50
Native Token	XDC
Block Time	~2 seconds
Epoch Length	900 blocks
RPC	https://rpc.xinfin.network
Explorer	https://xdc.blocksscan.io

Apothem Testnet¶

Parameter	Value
Chain ID	51
Native Token	TXDC (test)
Block Time	~2 seconds
RPC	https://rpc.apothem.network
Explorer	https://apothem.blocksscan.io
Faucet	https://faucet.blocksscan.io