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Guides

Setting Up Automated Compliance Checks for Contributors

A technical guide for developers on implementing automated rules engines to screen contributors against jurisdictional restrictions and sanction lists for permissioned token sales.
Chainscore © 2026
introduction
TOKEN SALE SECURITY

Setting Up Automated Compliance Checks for Contributors

This guide explains how to implement automated on-chain checks to verify contributor eligibility and enforce regulatory requirements during a token sale.

Automated compliance for token sales uses smart contracts to programmatically enforce rules before accepting contributions. This replaces manual KYC/AML reviews with deterministic, transparent logic executed on-chain. Core checks typically include verifying a contributor's wallet is not on a sanctions list, ensuring they are from a permitted jurisdiction, and limiting individual contribution amounts. Protocols like Chainalysis Oracle or TRM Labs provide on-chain oracles that feed real-world compliance data into your sale contract, enabling real-time validation.

The technical implementation involves integrating a compliance verification function into your token sale smart contract's contribution method. Before processing any transaction, the contract calls an external oracle or checks an on-chain registry. A basic Solidity pattern might use a modifier: modifier onlyCompliant(address _contributor) { require(complianceOracle.isAllowed(_contributor), "Address not allowed"); _; }. This modifier would then be applied to your contribute() function. Failed checks revert the transaction, preventing non-compliant capital from entering the sale.

For jurisdiction filtering, you need a reliable source of geolocation data. Services can map IP addresses or wallet addresses to countries. Your contract logic would then check against a list of allowed or blocked country codes. It's critical to design gas-efficient checks, as each oracle call adds cost. Consider using a commit-reveal scheme or batching checks off-chain with a merkle proof verification on-chain to reduce gas fees for contributors while maintaining security guarantees.

Beyond basic checks, advanced systems can handle accredited investor verification using attestations from licensed providers. Platforms like CoinList or Securitize integrate these checks directly into their sale infrastructure. For a custom solution, you could design a contract that accepts and verifies signed attestations from a trusted verifier's wallet. The signed message would confirm the investor's status, and your sale contract would verify the cryptographic signature before allowing a higher contribution tier.

Always audit your compliance logic thoroughly. A bug could incorrectly block legitimate users or, worse, allow prohibited ones. Use testnets to simulate contributions from various restricted and allowed addresses. Furthermore, consider the privacy implications of on-chain checks; using zero-knowledge proofs (ZKPs) via protocols like Aztec or Polygon ID can allow verification without exposing sensitive user data on the public ledger, balancing compliance with privacy.

prerequisites
SETUP GUIDE

Prerequisites and System Architecture

This guide outlines the technical foundation required to implement automated compliance checks for on-chain contributor activity, covering essential tools, system design, and initial configuration.

Before implementing automated compliance checks, you need a development environment with Node.js (v18+), a package manager like npm or Yarn, and a code editor. You will also require access to blockchain data, which can be sourced via a node provider API key from services like Alchemy, Infura, or QuickNode. For smart contract interaction, a wallet with testnet ETH (e.g., on Sepolia) and its private key is necessary. Finally, install the core libraries: ethers.js v6 for blockchain interactions and axios for making HTTP requests to external APIs.

The system architecture for automated checks typically follows a modular, event-driven pattern. A core orchestrator service polls for new on-chain events or listens via WebSocket subscriptions. When a relevant transaction is detected—such as a token transfer or governance vote—it extracts the contributor's address and routes the data to specialized check modules. Each module is responsible for a specific compliance rule, querying both on-chain data (like token holdings) and off-chain data (like sanctions lists) to produce a pass/fail result. Results are aggregated, logged, and can trigger automated actions via smart contracts.

Key architectural components include a persistent database (e.g., PostgreSQL) to store check results and contributor histories, a task queue (e.g., Bull with Redis) for handling asynchronous verification jobs, and a configuration manager to define which checks apply to different protocols or token standards. Security is paramount; the system must never expose private keys in client-side code. All sensitive operations, especially those requiring a signer, should be executed in a secure, backend environment. Environment variables should manage all API keys and RPC URLs.

Start by initializing your project and installing dependencies: npm init -y followed by npm install ethers axios. Configure your .env file with your RPC_URL, ALCHEMY_API_KEY, and WALLET_PRIVATE_KEY. The first script you should write is a simple connection test to verify RPC access and wallet connectivity using ethers.providers.JsonRpcProvider and new ethers.Wallet. This foundational step ensures your environment can successfully read from and write to the blockchain before adding complex logic.

Design your check modules as independent functions that accept a user address and return a standardized result object. For example, a checkSanctionsList module might call the OFAC API, while a checkTokenThreshold module queries an ERC-20 contract's balanceOf function. Use the factory or strategy pattern to allow easy addition of new checks. The orchestrator should iterate through an array of enabled modules, executing them in parallel with Promise.all for efficiency, and compile the results into a comprehensive report for the contributor in question.

Finally, consider scalability and maintenance from the outset. Implement robust error handling and logging (using winston or pino) for each module. Plan for rate limiting when calling external APIs and RPC endpoints. For production, you may need to deploy the service as a containerized application using Docker, with health checks and monitoring via Prometheus metrics. The initial architecture should be simple but structured to allow seamless integration with existing contributor management platforms or DAO tooling like Snapshot or Collab.Land in future iterations.

key-concepts
IMPLEMENTATION GUIDE

Core Components of a Compliance Engine

Automated compliance for on-chain contributors requires integrating specific technical modules. This guide outlines the essential components to build or integrate into your system.

03

Jurisdictional Rule Engine

Define and enforce rules based on a contributor's geographic location or jurisdiction. This component:

  • Uses IP geolocation or proof-of-residence attestations to determine jurisdiction.
  • Executes a set of programmable compliance rules (e.g., "users from Region X cannot contribute to Project Y").
  • Can be built using smart contract logic or off-chain services with on-chain verification, allowing for complex, conditional logic beyond simple blocklists.
OFAC
Primary Sanctions List
04

Transaction Monitoring & Limit Management

Monitor contribution patterns and enforce limits to prevent money laundering or regulatory breaches. Key functions include:

  • Setting and enforcing contribution caps per user, per time period (daily, monthly).
  • Tracking aggregate funding from specific jurisdictions.
  • Flagging suspicious patterns, such as rapid, small contributions (smurfing) or transactions just below reporting thresholds. This often requires an off-chain database to track historical activity across blocks.
05

Audit Logging & Reporting

Maintain an immutable, detailed record of all compliance decisions for regulators and internal review. This audit trail must include:

  • Timestamp, user address, and action taken.
  • The specific rule triggered and data used for the decision (e.g., risk score, jurisdiction).
  • The final outcome (approved, blocked, flagged). Logs should be stored in a tamper-evident system, such as IPFS with on-chain anchoring or a dedicated compliance database with strict access controls.
step-1-data-integration
AUTOMATED COMPLIANCE

Step 1: Integrating External Data Sources

This guide explains how to programmatically integrate external data sources to automate compliance checks for on-chain contributors, using Chainlink Functions and OpenZeppelin Defender.

Automated compliance checks require reliable access to off-chain data, such as sanctions lists, KYC status, or jurisdictional restrictions. Manually verifying this data is inefficient and prone to error. Instead, developers can use oracle networks like Chainlink to fetch and deliver verified external data directly to their smart contracts. This creates a trust-minimized system where compliance logic executes automatically based on real-world information, ensuring only approved contributors can interact with your protocol.

The core technical component is an oracle—a service that bridges on-chain and off-chain systems. For custom logic, Chainlink Functions provides a serverless environment to run JavaScript code that can call any public API. A typical compliance function might query the Office of Foreign Assets Control (OFAC) Specially Designated Nationals (SDN) list or an internal permissions database. The returned data, such as a boolean isApproved flag, is then signed by decentralized oracle nodes and sent back to your smart contract for on-chain verification.

Here is a simplified example of a Chainlink Functions JavaScript source code that checks an address against a mock compliance API:

javascript
const axios = require('axios');
const userAddress = args[0];
const apiResponse = await axios.get(`https://api.compliance-service.example/check/${userAddress}`);
return Functions.encodeUint256(apiResponse.data.isSanctioned ? 0 : 1);

This code retrieves a user's address from the request args, calls an external API, and encodes the result (where 1 means approved) for on-chain consumption. The smart contract would then store or act upon this result.

To automate the execution of these checks, you can use a service like OpenZeppelin Defender. Defender Autotasks can be scheduled to trigger your Chainlink Function at regular intervals or based on specific events, such as a new user registration on your dApp. This creates a fully automated pipeline: an event triggers a Defender Autotask, which calls the Chainlink Function, which fetches the latest compliance data and updates the on-chain contract state—all without manual intervention.

When designing this system, key considerations include data freshness, cost, and failure handling. You must decide how frequently to update compliance statuses, as oracle calls incur LINK token costs. Your contract should also handle scenarios where the oracle call fails or returns stale data, potentially by reverting transactions or placing users in a temporary pending state. Using a decentralized oracle network with multiple nodes mitigates single points of failure.

By integrating external data sources through oracle networks, you build a robust foundation for automated compliance. The next step is to define the on-chain logic in your smart contract that consumes this data to enforce rules, manage contributor permissions, and trigger automated actions based on their compliance status.

step-2-rules-engine
CORE LOGIC

Step 2: Building the Rules Engine Logic

Define the programmable conditions that automatically evaluate contributor actions against your project's governance and quality standards.

The rules engine is the core of your automated compliance system. It's a set of conditional statements, or rules, that programmatically check if a contributor's on-chain or off-chain actions meet predefined criteria. Think of it as an if-then system for governance: if a condition is met, then a specific action is triggered. For example, a rule could state: if a contributor's wallet holds less than 100 project tokens, then they cannot create a proposal in the governance forum. You define these rules using a combination of smart contract calls, API queries, and logical operators.

Rules typically evaluate data from multiple sources. Common data points include: - On-chain data: Token balance, voting history, transaction volume, or NFT ownership verified via a smart contract call. - Off-chain data: GitHub commit history, forum post count, or Discord role membership fetched from an API. - Temporal data: Account age, time since last action, or participation frequency. A single rule might combine these, such as requiring a minimum token balance and a verified GitHub account that is at least 30 days old before granting proposal creation rights.

To implement this, you'll write the rule logic in your backend service or within an off-chain keeper. Here's a simplified pseudocode example for a basic eligibility check:

javascript
async function checkProposalEligibility(walletAddress) {
  const minTokens = ethers.utils.parseEther("100");
  const tokenContract = new ethers.Contract(TOKEN_ADDRESS, ABI, provider);
  
  // Check on-chain token balance
  const balance = await tokenContract.balanceOf(walletAddress);
  const hasTokens = balance.gte(minTokens);
  
  // Check off-chain GitHub contributions (mock API call)
  const ghContributions = await fetchGitHubContributions(walletAddress);
  const hasContributions = ghContributions > 5;
  
  // Rule: Must have both tokens AND contributions
  return hasTokens && hasContributions;
}

This function returns a boolean that determines if the action (e.g., submitting a proposal) is permitted.

For more complex, multi-step workflows, consider using a dedicated rules engine library like JSON Logic or Nools. These allow you to define rules as declarative JSON objects, making them easier to manage, update, and audit without redeploying code. A JSON Logic rule for the above example might look like this, which can be stored in a database and interpreted by your service:

json
{
  "and": [
    { ">=": [
      { "var": "tokenBalance" },
      100000000000000000000
    ]},
    { ">": [
      { "var": "githubCommits" },
      5
    ]}
  ]
}

Finally, ensure your rules engine is modular and upgradeable. Rules will evolve as your community grows. Design your system so that new rules can be added, and existing ones modified or deprecated, through a transparent governance process—potentially even an on-chain vote. This keeps the compliance framework adaptable and aligned with the community's current standards, without requiring a full system overhaul for every policy change.

step-3-workflow-automation
AUTOMATING COMPLIANCE

Step 3: Configuring Automated Accept/Reject Workflows

Automated workflows enforce your grant program's rules by programmatically evaluating and processing contributor submissions, reducing manual review overhead and ensuring consistent, objective decisions.

An automated workflow is a set of predefined rules that your grant program executes against each incoming application or milestone submission. These rules are encoded as smart contracts or backend logic that can check for criteria like: wallet ownership verification, proof of completion (e.g., a GitHub commit hash or deployed contract address), adherence to submission deadlines, and required documentation. When a submission is received, the workflow automatically evaluates it against these conditions and triggers an accept, reject, or flag for review action without requiring manual intervention.

To implement this, you define the acceptance logic in code. For on-chain grants, this is often done with a smart contract. For example, a contract for a code completion grant could automatically approve a milestone when a verifiable transaction hash proving a deployment to a testnet is submitted. Off-chain, you might use a serverless function or a tool like Chainscore's API to check if a contributor's GitHub PR has been merged into the main branch of the specified repository. The key is to make the success criteria objective and machine-verifiable to minimize ambiguity.

Start by mapping your grant's requirements to specific, checkable data points. For a bug bounty, the rule might be: IF (a vulnerability report includes a PoC) AND (the issue is classified as High/Critical by a scoring system like CVSS) AND (the reported contract is in scope) THEN auto-approve for review. You then codify this using conditional statements in your chosen platform. Always include a manual override function for edge cases, allowing admins to manually accept or reject submissions that the automated rules cannot properly assess.

Testing your workflow is critical. Use a staging environment with test submissions to verify that the automation correctly identifies both valid and invalid applications. Common pitfalls include overly strict rules that reject valid work, or rules that can be gamed by malicious actors. For instance, a rule that only checks for a GitHub commit hash could be fooled by an empty commit. A more robust check would also verify that the commit contains actual code changes to the relevant files.

Finally, integrate the workflow's output with your grant management system. An approved submission should automatically trigger the next step in your process, such as moving the application to a "Ready for Payment" queue or initiating a token transfer on-chain. A rejected submission should notify the contributor with a clear reason, referencing the specific rule that was not met. This transparency builds trust and reduces support requests. Automated workflows transform your grant program from a manual, error-prone process into a scalable, efficient engine for distributing funds.

step-4-audit-logging
AUTOMATED COMPLIANCE

Step 4: Implementing Immutable Audit Logs

This guide explains how to set up automated, on-chain compliance checks for project contributors using immutable audit logs.

Immutable audit logs create a permanent, tamper-proof record of all contributor actions and compliance checks. By storing this data on-chain, you eliminate reliance on centralized databases and create a verifiable history that is accessible to all stakeholders. This is critical for regulatory compliance, internal governance, and security audits. The core mechanism involves emitting structured events from your smart contracts for every significant action, such as a new contributor being added, a KYC check being completed, or a transaction being approved.

To implement automated checks, you must define the compliance logic directly within your smart contracts. For example, a ContributorRegistry contract can require that a contributor's address has passed a verified KYC process with an oracle like Chainlink or API3 before they are whitelisted. The contract's addContributor function would check an external data feed; if the check passes, it mints an SBT (Soulbound Token) to the contributor and logs an event. This event, containing the contributor's address, timestamp, and attestation ID, becomes part of the immutable log.

Here is a simplified Solidity example of a function that performs an automated check and logs the result. It assumes an external oracle has already attested to the contributor's status and stored a mapping.

solidity
event ContributorVerified(address indexed contributor, uint256 timestamp, bytes32 attestationId);

mapping(address => bool) public isVerifiedContributor;
mapping(address => bytes32) public attestationIds;

function addVerifiedContributor(address _contributor, bytes32 _attestationId) external onlyOwner {
    // In practice, this would verify a signature or call an oracle
    require(_attestationId != bytes32(0), "Invalid attestation");
    
    isVerifiedContributor[_contributor] = true;
    attestationIds[_contributor] = _attestationId;
    
    // Emit the immutable log entry
    emit ContributorVerified(_contributor, block.timestamp, _attestationId);
}

For off-chain data or complex rule sets, consider using a verifiable credentials standard like W3C Verifiable Credentials or EIP-712 signed attestations. A contributor could present a credential signed by a trusted issuer (e.g., a legal entity). Your smart contract verifies the cryptographic signature on-chain before granting access. This pattern separates the issuance of compliance proof from its verification, allowing for flexible and privacy-preserving checks. The verification event is still logged immutably.

To make these logs actionable, you need to index and query them. Use a blockchain indexer like The Graph or Covalent to create a subgraph that listens for your ContributorVerified and related events. This allows you to build a dashboard that shows real-time compliance status, audit trails, and flags any addresses attempting to operate without proper credentials. The combination of on-chain enforcement and indexed, queryable logs creates a robust automated compliance system.

Finally, integrate these checks into your project's workflow. Before a contributor can interact with a treasury Multisig, execute a protocol upgrade, or receive tokens, the relevant contract should check isVerifiedContributor[msg.sender]. This automated gatekeeping ensures policy is enforced by code, not manual review. Regularly audit the logic of these checks and the security of any external oracles or signers they depend on to maintain the system's integrity.

DATA SOURCES

Comparison of KYC and Sanctions Data Providers

Key metrics and features for selecting a provider for automated compliance screening.

FeatureChainalysisEllipticTRM LabsComplyAdvantage

Sanctions List Coverage

OFAC, UN, EU, 50+ lists

OFAC, UN, EU, 40+ lists

OFAC, UN, EU, 60+ lists

OFAC, UN, EU, 80+ lists

Real-time PEP Screening

Adverse Media Monitoring

On-chain Transaction Monitoring

Average API Latency

< 500 ms

< 800 ms

< 400 ms

< 1 sec

Enterprise SLA Uptime

99.99%

99.9%

99.99%

99.5%

Direct VASP Directory Integration

Pricing Model (Enterprise)

Custom Quote

Custom Quote

Custom Quote

Tiered Subscription

AUTOMATED COMPLIANCE CHECKS

Common Implementation Issues and Troubleshooting

Automating compliance for on-chain contributors involves integrating multiple data sources and smart contract logic. Developers often encounter issues with data freshness, gas costs, and edge cases in permissioning logic. This guide addresses the most frequent technical hurdles.

Stale data typically originates from using off-chain indexers or APIs without proper caching or update mechanisms. For example, querying a contributor's token balance from a node's eth_getBalance provides a real-time snapshot but is gas-intensive for batch checks.

Common causes and fixes:

  • RPC Latency: Use a dedicated RPC provider with WebSocket support for real-time event listening instead of polling.
  • Indexer Lag: If using The Graph or Covalent, check subgraph syncing status or use their streaming APIs.
  • State vs. Event Data: For historical compliance (e.g., "held 1 ETH for 30 days"), you must analyze event logs, not just the current state. Use a service like Etherscan's API or Alchemy's Transfers API to reconstruct historical balances.
  • Solution Pattern: Implement a hybrid approach: cache on-chain data in your backend with a TTL and use events to invalidate the cache when relevant transactions occur.
TROUBLESHOOTING

Frequently Asked Questions on Automated Compliance

Common questions and solutions for developers implementing automated compliance checks for on-chain contributors.

A compliance check can fail for a valid wallet due to several common configuration issues. First, verify the block explorer API you are using (e.g., Etherscan, Snowtrace) has a valid API key with sufficient rate limits; many public endpoints are rate-limited. Second, confirm the smart contract address for your compliance rules (like a token or NFT contract) is correct for the intended network (e.g., using the Ethereum mainnet address on Polygon will fail). Third, ensure your query logic accounts for the finality of the chain; queries on networks with probabilistic finality (like some L2s) may need to check blocks with sufficient confirmations. Finally, check for data indexing delays; some explorers or subgraphs can be minutes behind the chain head, causing false negatives.

conclusion
IMPLEMENTATION

Conclusion and Next Steps

You have now configured a foundational system for automated contributor compliance. This guide covered the essential components: setting up a GitHub Actions workflow, integrating with the Chainscore API, and establishing a policy enforcement mechanism.

The workflow you've built automates the critical checks for every pull request: verifying contributor identity via a signed message, checking for Sybil behavior against the Chainscore database, and enforcing your project's specific policy rules. This moves compliance from a manual, error-prone process to a consistent, transparent, and automated gatekeeper. By integrating these checks into your CI/CD pipeline, you ensure that only verified, non-Sybil contributors can merge code, significantly reducing the risk of airdrop farming, spam, and governance attacks.

To extend this system, consider implementing more granular policies. For instance, you could create tiered access based on a contributor's Chainscore reputation_score or contribution_depth. Contributors with higher scores might bypass certain checks or gain automatic merge rights. You could also log all compliance events to a dashboard or database for audit trails and analytics. Explore the Chainscore API documentation for additional endpoints, such as fetching detailed on-chain history or contribution graphs for deeper analysis.

The next step is to test your workflow thoroughly in a staging environment. Create test PRs from accounts with varying Chainscore states to ensure your policy logic behaves as expected. Monitor the GitHub Actions logs and adjust your policy.yml rules as needed. For production use, ensure your GitHub repository secrets are properly secured and consider setting up notifications (e.g., Slack, Discord) for policy violations. Automating compliance is an ongoing process; regularly review and update your rules to adapt to new threats and your project's evolving needs.

How to Set Up Automated Compliance Checks for Token Sales | ChainScore Guides