Restrict Eligible Holders - Base Documentation

Create an allowlist in the Policy Registry, then apply it when shares are issued, sent, or received. Accounts remain ineligible until the policy admin adds them.

Demo

New to B20? See the B20 Token Standard for the concepts and a full launch walkthrough. These samples target base-std@v1.0.0, viem@2.55.11, and Base Foundry v1.1.1.

Create and bind the eligibility policy

import { parseEventLogs, type Address } from "viem";
import { account } from "../../shared/clients.js";
import { POLICY_REGISTRY, b20Abi, policyRegistryAbi, scope } from "../abi.js";
import { sendContract } from "../write.js";

export async function restrictStockHolders(token: Address, holders: Address[]) {
  const receipt = await sendContract({ address: POLICY_REGISTRY, abi: policyRegistryAbi, functionName: "createPolicyWithAccounts", args: [account.address, 1, holders] });
  const [created] = parseEventLogs({ abi: policyRegistryAbi, logs: receipt.logs, eventName: "PolicyCreated" });
  for (const policyScope of [scope("MINT_RECEIVER_POLICY"), scope("TRANSFER_SENDER_POLICY"), scope("TRANSFER_RECEIVER_POLICY")]) {
    await sendContract({ address: token, abi: b20Abi, functionName: "updatePolicy", args: [policyScope, created.args.policyId] });
  }
  return created.args.policyId;
}

    function restrictStock(address token, address admin, address[] memory holders) public returns (uint64 id) {
        id = StdPrecompiles.POLICY_REGISTRY.createPolicyWithAccounts(
            admin, IPolicyRegistry.PolicyType.ALLOWLIST, holders
        );
        IB20(token).updatePolicy(B20Constants.MINT_RECEIVER_POLICY, id);
        IB20(token).updatePolicy(B20Constants.TRANSFER_SENDER_POLICY, id);
        IB20(token).updatePolicy(B20Constants.TRANSFER_RECEIVER_POLICY, id);
    }

CREATE_TX=$(base-cast send "$POLICY_REGISTRY" \
  "createPolicyWithAccounts(address,uint8,address[])" "$ADMIN" 1 "[$ALICE,$BOB]" \
  --rpc-url "$RPC_URL" --private-key "$PRIVATE_KEY" --json | jq -r .transactionHash)
POLICY_TOPIC=$(base-cast receipt "$CREATE_TX" --rpc-url "$RPC_URL" --json | jq -r '.logs[0].topics[1]')
POLICY_ID=$(base-cast to-dec "$POLICY_TOPIC")
for SCOPE in MINT_RECEIVER_POLICY TRANSFER_SENDER_POLICY TRANSFER_RECEIVER_POLICY; do
  base-cast send "$TOKEN_ADDRESS" "updatePolicy(bytes32,uint64)" "$(base-cast keccak "$SCOPE")" "$POLICY_ID" \
    --rpc-url "$RPC_URL" --private-key "$PRIVATE_KEY"
done

See the complete verified B20 examples for imports, client construction, and runnable projects.

The same allowlist policy gates mint recipients, transfer senders, and transfer recipients.

Seed all intended holders before binding an allowlist. An unlisted account becomes ineligible immediately.

See also

Cancel blocked shares · Pause transfers
Policy Registry and Policy integration in the B20 standard

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