Reconcile With Memos

Tag stablecoin operations with an onchain reference so you can match them to offchain records at scale.

Tie onchain activity back to your books. A memo attaches a bytes32 reference to an operation and emits a Memo event alongside it, so reconciliation is a log query instead of a deposit address per customer. Every core call has a memo variant: mintWithMemo, burnWithMemo, transferWithMemo, and transferFromWithMemo.

Demo

Complete Launch a B20 token first. These samples target base-std@v1.0.0, viem@2.55.11, and Base Foundry v1.1.1.

Attach and read an invoice memo

TypeScript

import { hexToString, parseEventLogs, parseUnits, stringToHex, type Address } from "viem";
import { b20Abi } from "../abi.js";
import { sendContract } from "../write.js";

export async function payWithMemo(token: Address, merchant: Address) {
  const memo = stringToHex("invoice-8842", { size: 32 });
  const receipt = await sendContract({
    address: token,
    abi: b20Abi,
    functionName: "transferWithMemo",
    args: [merchant, parseUnits("25", 6), memo],
  });
  const [event] = parseEventLogs({ abi: b20Abi, logs: receipt.logs, eventName: "Memo" });
  return hexToString(event.args.memo, { size: 32 }).replace(/\0+$/, "");
}

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

The receipt contains Transfer followed immediately by Memo, with invoice-8842 encoded as bytes32.

Join a memo to the preceding operation with (transactionHash, logIndex - 1). Keep the offchain invoice ID unique.

See also

• Accept a B20 payment for the app-side flow
• Query B20 events with the CDP SQL API to reconcile at scale