Coinbase Commerce alternative: Crypto Merchant vs Coinbase Commerce (2026)

// orders: your own data layer
app.post("/orders/:id/pay", async (req, res) => {
  const order = await orders.find(req.params.id);

  const r = await fetch("https://cryptomerchant.online/api/v1/invoices", {
    method: "POST",
    headers: {
      Authorization: `Bearer ${process.env.CM_SECRET_KEY}`,
      "Content-Type": "application/json",
    },
    body: JSON.stringify({
      amount: order.total, // for example "49.90"
      currency: "USD",
      order_id: order.id,
      redirect_url: `https://yourstore.example/orders/${order.id}`,
    }),
  });
  if (!r.ok) {
    const { error } = await r.json();
    throw new Error(`${error.code}: ${error.message}`);
  }

  const invoice = await r.json();
  await orders.update(order.id, { invoiceId: invoice.id });
  res.redirect(303, invoice.checkout_url);
});

import crypto from "node:crypto";
import express from "express";

// CM-Signature: t=<unix seconds>,v1=<hex HMAC-SHA256 of "<t>.<raw body>">
function verify(rawBody, header, secret) {
  const parts = Object.fromEntries(
    String(header ?? "").split(",").map((p) => p.trim().split("=")),
  );
  if (!parts.t || !parts.v1) return false;
  const expected = crypto
    .createHmac("sha256", secret) // your endpoint secret, whsec_…
    .update(`${parts.t}.${rawBody}`)
    .digest("hex");
  const a = Buffer.from(expected);
  const b = Buffer.from(parts.v1);
  if (a.length !== b.length || !crypto.timingSafeEqual(a, b)) return false;
  return Math.abs(Date.now() / 1000 - Number(parts.t)) <= 300; // 5 minutes
}

const app = express();

// db, tx.webhookEvents, tx.orders: your own data layer
app.post(
  "/webhooks/crypto-merchant",
  express.raw({ type: "application/json" }), // keep the raw body for the signature
  async (req, res) => {
    const raw = req.body.toString("utf8");
    if (!verify(raw, req.get("CM-Signature"), process.env.CM_WEBHOOK_SECRET)) {
      return res.sendStatus(400);
    }
    const event = JSON.parse(raw);
    const invoice = event.data;

    try {
      await db.transaction(async (tx) => {
        // A unique key on the event id: a repeated delivery is skipped.
        const isNew = await tx.webhookEvents.insertIfAbsent(event.id);
        if (!isNew) return;

        if (event.type === "invoice.paid") {
          await tx.orders.markPaid(invoice.order_id, invoice.id); // one-way: never moves back
        } else if (event.type === "invoice.expired" || event.type === "invoice.cancelled") {
          await tx.orders.cancelIfUnpaid(invoice.order_id);
        }
      });
    } catch {
      return res.sendStatus(500); // not 2xx: Crypto Merchant tries again later
    }
    res.sendStatus(200); // within 10 seconds
  },
);

// Every paid invoice, newest first. Match each one to an order by order_id.
async function paidInvoices() {
  const all = [];
  let after = null;
  do {
    const url = new URL("https://cryptomerchant.online/api/v1/invoices");
    url.searchParams.set("status", "paid");
    url.searchParams.set("limit", "100");
    if (after) url.searchParams.set("starting_after", after);

    const r = await fetch(url, {
      headers: { Authorization: `Bearer ${process.env.CM_SECRET_KEY}` },
    });
    const page = await r.json();
    all.push(...page.data);
    after = page.has_more ? page.data[page.data.length - 1].id : null;
  } while (after);
  return all;
}