Setting Up Compliance for Non-EVM Deployments

Deploying compliance tooling on non-EVM chains requires a fundamentally different approach than on Ethereum. While EVM chains share a common execution environment, non-EVM ecosystems like Solana (Sealevel VM), Cosmos (CosmWasm), and Stellar have unique architectures, data structures, and smart contract models. This means standard EVM-centric solutions for address screening, transaction monitoring, and regulatory reporting cannot be directly ported. Developers must build or integrate compliance logic that interacts natively with each chain's specific runtime, state model, and transaction format.

The first step is understanding the data availability and primitives of your target chain. For transaction monitoring, you need reliable access to mempool data and finalized blocks. On Solana, this involves subscribing to the JSON-RPC getProgramAccounts or WebSocket streams for specific accounts. For Cosmos SDK chains, you query the Tendermint RPC for transactions and events. Tools must parse chain-specific transaction formats—like Solana's VersionedTransaction or Cosmos' Tx—to extract critical fields: sender, receiver, amount, and smart contract interactions.

Implementing sanctions screening requires mapping external compliance lists (e.g., OFAC SDN) to the native address formats of each chain. This is not a simple 1:1 mapping. On Bitcoin-like UTXO chains or Stellar, you screen output addresses and memo fields. For account-model chains like Solana or Algorand, you monitor the base58 or bech32 addresses of involved accounts. A robust setup involves running or connecting to an indexer that normalizes this cross-chain data into a unified format for screening against real-time threat intelligence feeds.

Smart contract-level compliance, such as pause functions or allow/deny lists, must be written in the chain's native smart contract language. For example, a compliance module on a Cosmos chain would be a CosmWasm contract exposing query and execute messages for validation. On Solana, you would write a program in Rust using the solana-program crate, embedding logic to check a central authority account before permitting a transaction. These contracts need secure, upgradeable administration patterns to manage listed addresses or risk parameters.

Finally, reporting and audit trails are crucial. Compliance deployments must log all screened transactions, alerts, and overrides. This involves writing events from your compliance logic to the chain where possible (e.g., using Solana's log instruction or Cosmos events) and maintaining off-chain databases for complex analysis. Integrating with oracles or inter-blockchain communication (IBC) protocols can be necessary for chains that need to verify compliance status or share alerts across ecosystems, creating a unified framework for decentralized application governance.

Compliance in blockchain refers to the technical mechanisms that allow applications to adhere to jurisdictional regulations, such as sanctions screening or transaction monitoring. For non-EVM chains like Solana, Cosmos, or Stellar, this involves interfacing with specialized compliance oracles and policy engines that operate off-chain. The core prerequisite is understanding your chain's unique architecture: its transaction format, account model, and how smart contracts (or their equivalents, like Solana programs or CosmWasm contracts) can initiate and validate external data requests.

Before integration, you must select a compliance provider. Services like Chainalysis KYT, Elliptic, or TRM Labs offer APIs that screen wallet addresses and transaction hashes against global watchlists. Your deployment needs a secure, reliable method to query these services. This typically involves setting up a dedicated off-chain relayer or oracle service that your on-chain program can trust. For example, a Cosmos-based app might use a custom module that makes HTTP requests via IBC to a designated compliance zone.

The next core concept is policy enforcement. It's not enough to just receive risk data; your application must define and execute rules based on that data. This requires embedding logic to handle compliance outcomes: allowing, flagging, or blocking transactions. On Solana, a program might include a check that consults a Verified Oracle Account for a compliance score before executing a transfer. You'll need to design your state management to store and reference these attestations, ensuring they are immutable and tamper-proof.

Key technical prerequisites include: securing API keys for your compliance provider, configuring RPC endpoints for your non-EVM chain, and establishing a signing authority for your oracle or relayer. For a Stellar deployment, this means managing secret keys for accounts that will submit ManageData operations containing compliance proofs. Testing is critical; you should deploy to a testnet and use the provider's sandbox environment to simulate high-risk addresses and transaction patterns before going live.

Finally, consider the data privacy and finality trade-offs. Sending every transaction detail to a third-party API can be a privacy concern. Some architectures use zero-knowledge proofs to validate compliance without exposing underlying data. Additionally, the asynchronous nature of oracle responses can conflict with your chain's block time. You must design your application's flow to handle delayed or failed compliance checks gracefully, potentially using conditional escrows or stateful pending statuses.

Integrating compliance into a Solana program requires a different approach than on EVM chains. Solana's architecture uses programs (smart contracts) and a unique account model. The core process involves intercepting transaction instructions, analyzing them with an external API like Chainscore, and conditionally halting execution based on the risk score. This is typically implemented using a CPI (Cross-Program Invocation) to a dedicated compliance program or a pre-execution hook in your program's instruction handler.

First, define the compliance check logic within your program's instruction handler. Before processing the core business logic, your program should serialize the relevant transaction details—such as the signer's public key, the program ID, and instruction data—into a structured format. This data is then passed to a compliance verification function. In Solana, you cannot make synchronous HTTP calls from on-chain programs, so this check must be performed client-side before submission or via a CPI to a separate oracle program that has off-chain data access.

For a client-side implementation, you would use the Chainscore API in your frontend or backend. Before building and sending the transaction to the network, you call the /v1/scan/address endpoint with the user's wallet address and the /v1/scan/transaction endpoint with a simulation of the transaction data. If the response indicates a high-risk score or a sanctioned address, you can prevent the transaction from being sent. This method provides a strong compliance gate without modifying the on-chain program.

For a more robust, on-chain enforcement, you can design a CPI pattern. Your main program would invoke a dedicated compliance oracle program. This oracle program would have a trusted off-chain relayer (oracle) that posts risk scores to its account data. Your program reads this data and aborts the transaction if risks are detected. While more complex, this ensures compliance is enforced at the protocol level, independent of client behavior. The Solana Cookbook provides excellent references for CPI and oracle patterns.

Key Solana-specific considerations include accounting for compute unit costs of the compliance check, managing program derived addresses (PDAs) for storing state, and ensuring the compliance logic adheres to the Solana runtime's constraints. Testing is crucial: use the solana-test-validator and the Chainscore testnet API to simulate high-risk transactions and verify your program correctly rejects them. This setup future-proofs your application against evolving regulatory requirements across all chains.

The Cosmos SDK's modular architecture allows developers to build custom application-specific blockchains. To implement compliance features like transaction screening, you create a dedicated x/compliance module. Start by scaffolding the module using the ignite scaffold module command, which generates the necessary directory structure, MsgService, and Keeper. The core logic for checking addresses against a sanctions list or validating transaction metadata will reside in the module's MsgServer and AnteHandler.

Within your new module, define the key data structures in types.go. This typically includes a ComplianceRule type to store rules (e.g., rule_type, target_address, status) and a ViolationRecord to log blocked transactions. The module's Keeper manages the state of these rules and records, providing methods like SetRule and GetViolations. You must also define protobuf messages for governance proposals to add or update rules, ensuring decentralized control over the compliance parameters.

The primary enforcement point is a custom AnteHandler decorator. This function intercepts transactions before they enter the mempool or are included in a block. Your AnteHandler should: 1) decode the transaction messages, 2) extract sender and receiver addresses from MsgTransfer or similar, 3) query the compliance module's Keeper to check these addresses against the active rule set, and 4) return an error if a violation is detected. This prevents non-compliant transactions from being processed.

For real-time screening, you can integrate with external services. Implement a querier or MsgServer method that calls an oracle or API (e.g., Chainalysis or a custom service) and posts the result to the blockchain state via a governance proposal or a permissioned oracle module. A more decentralized approach involves creating a proof-of-compliance zk-SNARK circuit that validators can verify, though this requires significant cryptographic integration.

Finally, thoroughly test your module. Use the Cosmos SDK's simapp for unit tests on the Keeper logic and the AnteHandler. Write integration tests that simulate multi-block scenarios with compliant and non-compliant transactions. Ensure your module correctly interfaces with other core modules like bank and gov. Document the new transaction types and query endpoints for wallet and exchange integrators.

Deploying a compliance layer on a non-EVM chain like Solana, Cosmos (with CosmWasm), or Aptos Move requires a fundamentally different approach to testing than on Ethereum. The core principles—ensuring sanctions screening, transaction monitoring, and policy enforcement work as intended—remain the same. However, the tooling, smart contract paradigms, and runtime environments are distinct. Your testing strategy must account for chain-specific account models, transaction formats, and state management to guarantee that your compliance rules are correctly executed on-chain.

The first step is establishing a robust local testing environment. For Solana, this means using solana-test-validator and frameworks like anchor test or the Solana Program Library's test utilities. For Cosmos chains, you'll work with wasmd for local CosmWasm simulation. These tools allow you to deploy your compliance program and run unit tests against a local node. Key tests should verify that your program correctly: intercepts and validates transaction instructions, queries your chosen oracle or API for sanction list data, and blocks or flags transactions based on your defined policy rules.

Integration testing is critical for verifying interactions with off-chain data providers. Your compliance program will likely need to call an oracle, like Pyth or Chainlink on Solana, or make HTTP queries via CosmWasm's IBC-enabled oracles. Mock these services in your tests to simulate various responses: a clean address, a sanctioned address, or a failed API call. Ensure your program handles each case appropriately—blocking the tx, allowing it, or entering a safe fallback state. Test edge cases like rate limiting, data staleness, and oracle downtime.

Formal auditing for non-EVM code requires specialized expertise. Engage auditors familiar with the specific language and chain security model. For Solana's Rust-based programs, auditors check for common pitfalls in the BPF loader, account privilege escalation, and cross-program invocation safety. For CosmWasm, they review IBC packet handling and query authorization. For Move-based chains (Aptos, Sui), they verify resource semantics and global storage patterns. Provide auditors with comprehensive documentation, a detailed specification of your compliance policy, and the full suite of your unit and integration tests.

Finally, implement a continuous monitoring and upgrade strategy. Post-deployment, use chain-specific explorers and indexers to track events emitted by your compliance program. Set up alerts for any policy violation events or failed rule executions. Plan for upgrades via your chain's governance mechanism (e.g., CosmWasm migration) or program deployment authority. Always test upgrades on a testnet—like Solana Devnet or a Cosmos test chain—with a full regression suite before proposing them to mainnet governance.

To move from theory to practice, begin by implementing the core monitoring tools discussed. For a Solana program, integrate the solana-web3.js library with your chosen RPC provider to track on-chain events. For Cosmos SDK chains, set up a Tendermint RPC subscription to listen for transaction broadcasts. The initial goal is to establish a reliable data ingestion pipeline that logs all relevant activity from your deployment, which forms the foundation for all subsequent compliance checks.

Next, develop and deploy your custom compliance smart contracts or logic. On Algorand, write a stateful smart contract in TEAL that validates transaction parameters against a whitelist stored in global state. For a Starknet application, use Cairo to create a contract that verifies user credentials via a zero-knowledge proof. Rigorously test these contracts on testnets like Algorand TestNet or Starknet Goerli to ensure they correctly enforce rules without disrupting core application functionality.

Finally, establish a review and reporting workflow. Schedule regular audits of the compliance logs, using the indexed data to generate reports for internal review or regulatory submission. Proactively monitor for anomalies, such as a spike in transaction volume from a single address on your Sui Move application. The ecosystem for non-EVM tooling is rapidly evolving; subscribe to developer forums and governance channels for your chosen chain (e.g., Solana Stack Exchange, Cosmos Forum) to stay updated on new best practices and security advisories.