Webhook Reliability and Idempotency Guarantees

[grantfox-oss]

src/webhook.rs, src/event.rs, src/config.rs, src/metrics.rs, src/main.rs, src/cache.rs
Difficulty: Hard

Problem

Webhook delivery lacks strong idempotency guarantees. DLQ could lose data on restarts, and retry logic doesn't account for clock skew or webhook processing delays.

Current Issues

• DLQ stored in-memory, lost on process restart
• Idempotency key computed but not validated on webhook receiver
• No deduplication mechanism for retried deliveries
• Delivery ordering not guaranteed across multiple URLs
• No way to verify successful webhook processing
• Secret signing not explained in documentation

Required Changes

1. Persist DLQ to Redis for durability
2. Implement request signing with HMAC-SHA256 signature verification
3. Add deduplication service backed by Redis with TTL
4. Create webhook health check endpoint
5. Document idempotency protocol and receiver expectations
6. Implement exponential backoff with jitter for retries

Acceptance Criteria

• At-least-once delivery guarantee verified through tests
• Idempotent receivers can safely skip duplicate deliveries
• DLQ recoverable after process restart
• Webhook security guide in documentation

[Silver36-ship-it]

I would love to work on this professionally, please assign it to me

[divinemike019]

I’d like to contribute to this issue because improving the reliability and resilience of distributed systems is an area I genuinely enjoy working on. The challenge of strengthening webhook delivery, ensuring idempotency, and handling failure scenarios such as retries, clock skew, processing delays, and DLQ persistence is fundamental to building dependable production systems.
My approach will be to first understand the existing webhook pipeline and event lifecycle before implementing targeted improvements that preserve current behavior while addressing the identified reliability gaps. I'll ensure idempotent event processing, review retry and backoff logic, strengthen failure handling, and validate that dead-letter queue (DLQ) behavior remains durable across restarts. Where appropriate, I'll update documentation and add comprehensive tests covering edge cases to prevent regressions and improve long-term maintainability.
I have experience building backend systems, working with APIs, event-driven architectures, testing, debugging, and writing clean, maintainable code. I prioritize solutions that are secure, well-documented, and aligned with the project's architecture rather than introducing unnecessary complexity.
If assigned, I'll maintain clear communication throughout the implementation, keep the pull request focused on the issue scope, follow the repository's coding standards, and provide a production-ready contribution that reviewers can evaluate and merge with confidence. My goal is not only to resolve the issue but to improve the overall reliability and maintainability of the webhook infrastructure.

[Xhristin3]

Please assign me this issue

[grantfox-oss]

🦊 GrantFox — @Xhristin3 has been assigned to this issue as part of the Official Campaign | FWC26 campaign!

Next steps:

1. Open a Pull Request referencing this issue (e.g., Closes #47)
2. Your PR will be reviewed by the Proof-Stell maintainers

Good luck! Track your progress on GrantFox.

[grantfox-oss]

🎉 This issue has been marked as completed on GrantFox as part of the Official Campaign | FWC26 campaign!

@Xhristin3's PR #50 was approved and merged by @MaryammAli.

🏆 @Xhristin3: You earned 35 FoxPoints for this contribution! Your current tier: Explorer (274 total points). Track your full progress on GrantFox.

👏 Great work, @Xhristin3! Keep contributing to Proof-Stell.