Design an asynchronous dead-letter queue (DLQ) recovery API for stalled tRPC webhook mutations

[Damola-Sodiq]

Description

Build a robust Dead-Letter Queue (DLQ) system in the backend to catch, inspect, and replay failed smart contract webhook events.

Architecture & Context

When the Soroban RPC emits events to the backend, temporary database outages or malformed payloads can cause ingestion failures. A DLQ ensures these events are not lost but safely stored for programmatic or manual replay.

Technical Requirements

• Create a dedicated Prisma schema table to store raw, unprocessed JSON payloads and their error stack traces.
• Implement a cron-based Fastify worker to automatically retry transient errors with exponential backoff.
• Build a secured tRPC mutation to manually edit and replay poisoned payloads.

Acceptance Criteria

• Failed webhook events are strictly routed to the DLQ table.
• Exponential backoff successfully recovers transient database timeout errors.
• Poison messages do not block the active webhook ingestion pipeline.