payment-router

Some payment gateways for some reason only let you configure a single webhook URL. If you have multiple apps that need to receive payments then it is a nightmare to handle those cases. This project tries to solve this by acting as a router: you register your real webhook URL with this API, and then point the gateway at the worker's URL. The worker will forward the callback to your real webhook URL.

A hosted instance is live at https://payment-r.fanth.pl. You can also self-host this on Cloudflare Workers.

Supported gateways

Gateway	Callback endpoint	External ID field
PayU	https://router.example.com/webhooks/payu	extOrderId
Paymentic	https://router.example.com/webhooks/paymentic	externalReferenceId
PayNow	https://router.example.com/webhooks/paynow	externalId
Cashbill	https://router.example.com/webhooks/cashbill	additionalData

Each gateway's adapter lives in src/gateways/. Adding a new one is a single file, see that directory for the pattern.

1. Set notification url in your payment gateway dashboard

Set the notification URL according to the table above. Replace https://router.example.com with your own instance's public origin. The path is fixed per gateway.

2. Register your webhook on payment initalization

curl -X POST https://router.example.com/v1/routes \
  -H "Content-Type: application/json" \
  -d '{
        "webhookUrl": "https://shop.example.com/webhooks/paymentic",
        "expiresAt": "2026-07-12T10:00:00Z"
      }'

{
    "externalId": "3f6a1c0e-9a6b-4a5f-8d21-7c1b0f2e9d44",
    "webhookUrl": "https://shop.example.com/webhooks/paymentic",
    "expiresAt": "2026-07-12T10:00:00.000Z",
    "createdAt": "2026-07-11T12:00:00.000Z",
    "callbackUrls": { "paymentic": "https://router.example.com/webhooks/paymentic" }
}

externalId is a UUID generated for you - it is the value you send to the gateway and that callbacks are matched on. Keep it alongside your own order id so you can correlate the callback when it lands.

expiresAt is optional, defaults to 12h out.

3. Create transaction in your payment gateway

Create a transaction according to the gateway's API, using the externalId from the previous step as the external payment id. You can look up the correct field in the table above.

4. Verify the callback

The router forwards the gateway's request verbatim - same method, same body byte for byte, same headers - and adds nothing of its own. So verify it exactly as you would if the gateway called you directly: check the gateway's own signature (PayU's OpenPayU-Signature, PayNow's Signature, ...) against the raw body you received. Your externalId is inside that payload, where the gateway put it.

Notes

• Your webhook endpoint's response is passed straight back to the gateway. Return 2xx or the gateway will treat the callback as failed and retry.
• Route creation is rate-limited per IP (60/min by default).

Self-hosting

This is built for Cloudflare Workers (D1, wrangler) - to run 24/7 you need to deploy it there with pnpm deploy, not just run it locally.

npx wrangler d1 create payment-router   # paste the printed id into wrangler.jsonc
pnpm db:generate                        # regenerate SQL after schema changes
pnpm db:migrate:local                   # apply migrations to the local D1
pnpm db:migrate                         # apply migrations to the remote D1
pnpm dev                                # local dev only - stops when your machine does
pnpm deploy                             # ship it to Cloudflare Workers

Set PUBLIC_BASE_URL in wrangler.jsonc to the worker's public origin.