Backend: Implement Webhook Event Replay and Dead-Letter Queue Management

[Smartdevs17]

Context

Webhook delivery reliability is critical for merchants integrating with AgenticPay. Failed deliveries can result in missed payment notifications, order fulfillment delays, and merchant dissatisfaction.

Current Limitation/Problem

Webhook delivery has basic retry with exponential backoff, but no replay capability, no dead-letter queue for permanent failures, and no dashboard for monitoring delivery health.

Expected Outcome

A robust webhook delivery system with configurable retry policies, a dead-letter queue for persistently failing deliveries, manual replay capability, and a delivery health dashboard.

Acceptance Criteria

• Configurable retry policy per endpoint (max retries, backoff multiplier, timeout)
• Dead-letter queue with permanent failure categorization (invalid endpoint, bad signature, rate limited)
• Manual replay single or batch from DLQ via API
• Webhook delivery logs with response status, latency, and payload preview
• Dashboard showing delivery success rate, average latency, and failure breakdown
• Alert when delivery success rate drops below 99%
• Export delivery logs as CSV
• Support retry window expiration (discard after 7 days)

Technical Scope

• backend/src/services/webhooks/delivery-manager.ts - enhanced delivery logic
• backend/src/services/webhooks/dead-letter-queue.ts - DLQ management
• Prisma: WebhookDeliveryLog, WebhookDeadLetter, WebhookEndpoint enhancements
• BullMQ queues: webhook-delivery, webhook-dlq, webhook-replay
• Frontend: /dashboard/developers/webhooks - delivery health page
• Edge cases: endpoint permanently down, invalid SSL, payload too large

[maxim-ultra]

Hi - I looked at #453 from the payment-reliability angle. One risk worth isolating is: Public issue mentions payment, retry, replay, webhook; Backend: Implement Webhook Event Replay and Dead-Letter Queue Management.

A useful first check: trace webhook signature, replay, and idempotency boundaries into a public-only acceptance checklist. I would keep it public-only: no production access, no API keys, no wallet access, and no private customer data.

If useful, I can turn this into a compact Agent Payment Reliability Kit Scan: five checks across idempotency, webhook signature, retry, budget, and receipt attribution.

[JosephOladele]

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I would like to work on this issue

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[Adeyemi-cmd]

@Adeyemi-cmd has applied to work on this issue as part of the Stellar Wave Program's 6th wave.

Can I please work on this

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[akintewe]

@akintewe has applied to work on this issue as part of the Stellar Wave Program's 6th wave.

I've been creating intricate forms and e-commerce systems for more than four years as a full-stack developer. I have designed inventory management systems for agricultural enterprises and have experience with image processing and large-scale state management. I have also worked on this project in the past.
My ETA is one hour, and I would love to work on this problem.

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