Biomapper

How to enable Sybil resistance in your dApp on Sei Network?

Humanode Core

14 Mar 2025 • 3 min read

Building on Sei means you’re working with one of the fastest and most scalable Layer 1s designed specifically for decentralized trading. Sei’s twin-turbo consensus and parallel transaction processing make it an ideal platform for high-frequency trading, DEXs, and NFT marketplaces where speed and reliability are non-negotiable.

But with high-speed and low-latency trading comes a familiar problem: Sybil attacks. When transactions are fast and fees are low, malicious actors can generate multiple wallets to farm liquidity rewards, game trading incentives, and influence governance. If you’re building a DEX, NFT marketplace, or GameFi platform, protecting against multi-wallet exploitation is critical to maintaining fairness and market integrity.

That’s where Humanode Biomapper comes in. Biomapper allows you to verify that each wallet interacting with your dApp belongs to a unique human – without requiring KYC, document uploads, or personal data collection. This ensures Sybil-free liquidity mining, governance voting, and incentive programs while preserving user privacy.

Why Sybil Resistance Matters for dApps on Sei

Liquidity Incentives → Adding uniqueness check ensures that liquidity incentives doesn’t only depend on the TVL.
Governance Votes → Prevents governance capture by enforcing one-person-one-vote.
NFT Marketplaces → Stops wallet farming and bulk minting to increase floor prices artificially.
GameFi Rewards → Ensures that in-game incentives are fairly distributed to unique players.

How to enable Sybil resistance in your dApps on Sei

Before integrating Biomapper, familiarize yourself with core concepts such as:

Generations: Biomapper operates in fixed time-based generations. Each generation resets biometric mappings.
Integration Flow: Users verify uniqueness once, bridge their biomapping to the Sei network, and can be verified across multiple dApps.

What You Need to Do

Write a smart contract that interacts with the Bridged Biomapper on Sei.
Add a link to the Biomapper UI on your front end so users can complete their biomapping.

Integration Steps

1. Install the Biomapper SDK

The Biomapper SDK allows smart contracts on Sei to verify user uniqueness through the BridgedBiomapper.

Using npm:

npm install --save @biomapper-sdk/core @biomapper-sdk/libraries @biomapper-sdk/events

Using yarn:

yarn add @biomapper-sdk/core @biomapper-sdk/libraries @biomapper-sdk/events

Using Foundry:

forge install humanode-network/biomapper-sdk

2. Import Biomapper Interfaces & Libraries

In your Solidity contract, import the necessary interfaces:

// SPDX-License-Identifier: MIT
  
pragma solidity ^0.8.20;

import { IBridgedBiomapperRead } from "@biomapper-sdk/core/IBridgedBiomapperRead.sol";

import { IBiomapperLogRead } from "@biomapper-sdk/core/IBiomapperLogRead.sol";

import { BiomapperLogLib } from "@biomapper-sdk/libraries/BiomapperLogLib.sol";

These imports expose read-access functions to check a wallet’s biomapping status and uniqueness.

3. Connect to Bridged Biomapper

Sei already has BridgedBiomapper deployed, so you don’t need to deploy your own – just reference the existing contract.

Example: GameFi Reward Distribution

pragma solidity ^0.8.0;
import "@biomapper-sdk/core/IBridgedBiomapperRead.sol";
import "@openzeppelin/contracts/token/ERC20/IERC20.sol";
import "@openzeppelin/contracts/token/ERC20/utils/SafeERC20.sol";

  contract GameFiRewards {
    using SafeERC20 for IERC20;
    IBridgedBiomapperRead public biomapper;
    IERC20 public immutable REWARD_TOKEN;
    mapping(address => uint256) public playerScores;
    constructor(address _biomapperAddress, address _rewardToken) {
        biomapper = IBridgedBiomapperRead(_biomapperAddress);
        REWARD_TOKEN = IERC20(_rewardToken);
    }
    function distributeRewards(address player, uint256 rewardAmount) external {
        require(biomapper.isBridgedUnique(player), "User is not unique");
        require(playerScores[player] > 0, "No score recorded");
        REWARD_TOKEN.safeTransfer(player, rewardAmount);
        playerScores[player] = 0; // Reset score after reward
    }
    function updatePlayerScore(address player, uint256 score) external {
        playerScores[player] = score;
    }
}

This contract ensures that only unique players can receive rewards, stopping multi-wallet farming and unfair score boosting.

4. Local Testing with Mock Contracts

For local testing, use the MockBridgedBiomapper contract to simulate biomapping without hitting mainnet.

Example:

function generationsBridgingTxPointsListItem(uint256 ptr) external view returns (GenerationBridgingTxPoint memory);

Refer to Biomapper SDK Docs for full details on using mocks.

Frontend Integration

To complete user verification, link to the Biomapper App in your dApp UI.

Example Frontend Integration:

< a href="https://biomapper.hmnd.app" target="_blank">Verify Your Uniqueness< /a>

Once users complete their private face verification, they return to your dApp and interact Sybil-free.

Deployment & Rollout

1. Deploy the Smart Contract

Deploy your DEX, NFT marketplace, or GameFi contract to Sei Mainnet and link it to Bridged Biomapper.

2. Retrieve the Bridged Biomapper Contract Address

Find the latest contract addresses from the Biomapper SDK.

3. Update Frontend to Mainnet

Ensure your UI links to the mainnet Biomapper App.

4. Test Before Deployment

Use Sei testnet for pre-launch validation.
Confirm that biomapping checks prevent multi-wallet exploitation.
Log interactions to monitor anomalies in biomapping verification.

Post-Deployment & Maintenance

dApp Listing → Get featured in Humanode’s Biomapper ecosystem.
Ongoing Updates → Stay aligned with Biomapper SDK improvements.

Sei gives you the speed and scalability needed for high-frequency trading and real-time order execution. But for your dApp to be secure, fair, and Sybil-resistant, you need to ensure that each user is a real, unique human.

Biomapper makes it easy – no KYC, no identity exposure, just cryptographic proof of uniqueness. Whether you’re building a DEX, a GameFi platform, or NFT marketplace, Sybil resistance will give your platform the integrity it needs to scale securely.

Ready to integrate? Here are useful resources: