Compliant Dedicated Chains: Optional AML Screening Without Latency

TL;DR — When a dedicated chain adds optional compliance filters, you can keep AML screening off the validator hot path by running address checks at the custody-operator layer instead. Screen sender and recipient addresses with a single API call before you sign or broadcast, and let webhooks catch anything that lands on watched addresses after the fact. This keeps block production fast while satisfying MiCA and FATF Travel Rule obligations.

The problem

Arbitrum voted to activate Elara, a framework that lets teams launch dedicated chains with optional compliance filters, as The Defiant reported. The vote is the easy part. The engineering decision that follows is harder: where does screening actually run.

If you are the custody operator or payment service provider standing up a dedicated chain, putting sanctions and AML (Anti-Money Laundering) logic inside the validator means every block waits on an external lookup. That couples execution latency to a third-party screening service. One slow response degrades throughput for the whole chain. Most teams building crypto payment processors cannot accept that trade.

The practical pattern is to move screening out of consensus and into the operator layer, where you control the transaction lifecycle. You screen before you sign. You screen before you credit a deposit. Validators stay fast.

What you need

• A dedicated JSON-RPC (JSON Remote Procedure Call) endpoint for your chain. A shared or dedicated node as a service covers this without you running infrastructure.
• An address screening source that returns risk classification and sanctions matches. We expose this through GET /aml/addresses/{address}.
• A clear policy on what you block versus flag. Sanctions hits are a hard stop. Elevated-risk classifications may only warrant review. Encode this in your service, not in the chain.
• Webhook infrastructure for post-hoc monitoring. Deposits arrive on addresses you did not initiate, so you screen those on confirmation via blockchain events.

Be honest about the hard part: screening is a policy problem before it is an API problem. The call is simple. Deciding what a risk score means for a given jurisdiction, and documenting that decision for auditors, is the work.

How it works

Screen the recipient before you sign an outbound transfer. If the address returns a sanctions match, you never build the transaction. Call the AML endpoint with the address:

curl -X GET \
  "https://rest.cryptoapis.io/aml/addresses/0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045" \
  -H "Content-Type: application/json" \
  -H "x-api-key: YOUR_API_KEY"

The response returns a risk assessment for the queried address, including a risk classification you map to your own allow, review, or block rules. Read the classification, apply your policy, and only then proceed to build the transaction.

Once an address clears screening, prepare the outbound transfer. For an EVM (Ethereum Virtual Machine) chain, native-coin transfers go through prepare transactions:

POST https://rest.cryptoapis.io/prepare-transactions/evm/{blockchain}/{network}/native-coins

Sign the prepared payload in your own signing environment, then push it to the network:

POST https://rest.cryptoapis.io/broadcast-transactions/{blockchain}/{network}

For inbound deposits, screening cannot happen before the fact. You do not control who sends to your addresses. Subscribe to confirmed incoming transactions so you can screen the sender the moment funds land:

POST https://rest.cryptoapis.io/blockchain-events/{blockchain}/{network}/address-coins-transactions-confirmed

When the webhook fires, extract the sender address from the payload and run it through GET /aml/addresses/{address}. If it fails your policy, hold the credit and route it to manual review. This is the same monitoring pattern we describe in our guide to monitoring blockchain addresses with webhooks. Every screening decision runs off-chain, so validator performance never depends on it.

What to watch for

Screening returns a point-in-time result. An address clean today can be added to a sanctions list next week. Re-screen counterparties on a schedule for long-lived relationships, and always re-screen at the moment of a new transaction rather than trusting a cached verdict.

Webhook delivery is not guaranteed to be instant under every condition, though our events fire in under 100 milliseconds in normal operation. Build an idempotent handler keyed on transaction hash so a redelivered event does not double-process a deposit. If your endpoint is down, events queue and retry, so design the consumer to tolerate replays.

Coverage matters. If your dedicated chain settles or bridges to assets on Ethereum, Bitcoin, Solana, or other networks, screen across every chain a counterparty touches, not just the one your chain runs on. We cover this cross-chain requirement in detail in AML address screening across 17 chains before you credit a deposit.

Watch your policy mapping for false positives. A high-risk classification is not automatically a sanctions match. Blocking every elevated score will freeze legitimate users and generate support load. Separate hard stops from review queues in code, and log the reasoning behind each decision for MiCA (Markets in Crypto-Assets) and FATF (Financial Action Task Force) Travel Rule audit trails.

Rate limits apply per plan. Screening every address on a high-volume chain can consume request budget quickly, so batch where your policy allows and cache short-lived clean results for repeat internal transfers. Check current limits on the pricing page.

Optional compliance filters on dedicated chains work best when screening lives at the custody-operator layer, not inside consensus. Verify Address, exposed through GET /aml/addresses/{address}, gives you sanctions and AML screening across 20-plus chains with a single call, so you can keep block production fast and your obligations met. Start on the free crypto api tier, no credit card required, and see the full endpoint set under products.