See llms.txt for all machine-readable content.
Quick overview
This workflow receives failed-payment webhooks, logs retryable failures to a Google Sheets queue with reason-based retry timing, retries due payments on a 15-minute schedule via an HTTP payment API call, and notifies customers through Gmail when action is required, a payment succeeds, or retries are exhausted.
How it works
- Receives a POST webhook event for a failed payment and normalizes the payload into consistent fields.
- Checks Google Sheets (RetryQueue tab) for an existing row with the same event_id and stops if the event was already processed.
- Classifies the failure reason to either schedule an automatic retry (with delay and max retries) or mark it as customer action required.
- Appends the result to the Google Sheets RetryQueue and, for customer-action cases, sends a Gmail email asking the customer to update their payment method.
- Runs every 15 minutes, loads the Google Sheets RetryQueue, and filters to rows that are SCHEDULED, due now, and still below the max retry limit.
- Calls the payment provider’s retry endpoint via HTTP for each due row and interprets the response to determine success or failure.
- Updates the same Google Sheets row to SUCCESS and emails the customer on success, or schedules the next retry time (or marks MAX_RETRIES_REACHED) and emails the customer when retries are exhausted.
Setup
- Create a Google Sheet with a RetryQueue tab and column headers that match the fields used in the Google Sheets nodes (for example: id, event_id, transaction_id, payment_id, amount, currency, status, retry_count, max_retries, next_retry_at, last_retry_at, customer_email, failure_reason, failure_message).
- Add Google Sheets credentials in n8n and update each Google Sheets node to point to your spreadsheet (replace any YOUR_GOOGLE_SHEET_ID placeholders and select the correct document and sheet).
- Add a Gmail credential in n8n and confirm the “Notify Customer”, “Email Customer — Payment Successful”, and “Email Customer — Payment Failed” nodes use the correct sender and content for your use case.
- Set the HTTP Request node to your real payment retry endpoint (URL and authentication via headers/credentials) and verify the request/response fields align with how “Read Retry Result” detects success.
- Copy the “Receive Failed Payment” webhook URL from n8n and configure your payment system to POST failed payment events to it using the expected fields (event_id, transaction_id, customer_email, amount, currency, failure_reason/failure_code).
Additional info
Troubleshooting Guide
| Issue | Possible Cause | Solution |
|---|---|---|
Google Sheets Operation lookup shows red error |
Your n8n version removed/renamed Lookup | Use Get Row(s) + filter on event_id |
| Sheets node returns no data / fails | Still using YOUR_GOOGLE_SHEET_ID |
Replace with real Sheet ID and connect credential |
| Duplicate always true | Demo row already has same event_id |
Use a new event_id or clear the matching row |
| Auto-retry IF never goes false | failure_reason is still retryable (e.g. insufficient_funds) |
Send expired_card / invalid_card / authentication_required |
| Schedule finds no due rows | next_retry_at is in the future or status not SCHEDULED |
Backdate next_retry_at and set status=SCHEDULED |
| HTTP retry fails immediately | Placeholder payment URL / missing auth | Point to mock (e.g. httpbin) or real provider + credential |
| Success IF unexpected with httpbin | httpbin echoes request; not a real payment status | Use a mock that returns {"status":"succeeded"} or {"status":"failed"} |
| Gmail not received | Wrong email / missing Gmail credential | Use your real customer_email and reconnect Gmail |
| Webhook 404 | Workflow inactive or wrong path | Activate workflow; POST to /webhook/payment-failed (or test URL while listening) |
| Card data concerns | Payload includes sensitive fields | Send only payment IDs/tokens — never PAN/CVV |
Need Help?
If you need help customizing or extending this workflow, for ex. adding provider-specific retry APIs, CRM sync, Slack alerts, fraud checks or production hardening then WeblineIndia's n8n team can assist you with advanced automation.
Learn more: Everything in n8n Automation | Offshore Workflow Experts