Restrict who can hold it - Base Documentation

Keep your stablecoin within a known set of holders with an allowlist: transfers only settle between accounts your KYC program has approved. You manage the list in the Policy Registry and bind it to the token’s transfer scopes.

Demo

Set the allowlist

Terminal

REG=0x8453000000000000000000000000000000000002  # Policy Registry

# Create an ALLOWLIST policy (type 1), add approved accounts, bind sender + receiver.
base-cast send $REG "createPolicy(address,uint8)" $ADMIN 1 --rpc-url $RPC_URL --private-key $KEY
base-cast send $REG "updateAllowlist(uint64,bool,address[])" $POLICY_ID true "[$A,$B]" --rpc-url $RPC_URL --private-key $ADMIN_KEY
base-cast send $TOKEN_ADDRESS "updatePolicy(uint8,uint64)" $(base-cast keccak "TRANSFER_SENDER_POLICY") $POLICY_ID --rpc-url $RPC_URL --private-key $KEY
base-cast send $TOKEN_ADDRESS "updatePolicy(uint8,uint64)" $(base-cast keccak "TRANSFER_RECEIVER_POLICY") $POLICY_ID --rpc-url $RPC_URL --private-key $KEY

A B20 token is fully open by default. Confirm policyExists(policyId) before binding — an allowlist with no members denies everyone.

See also

Block an account
Policy integration in the B20 standard

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