Eliminate Webhook Data Loss. Zyvan is a high-performance, distributed middleware that guarantees at-least-once delivery between your core services and external endpoints. Built with Node.js, PostgreSQL, Redis, and a Next.js Dashboard.
Calling external webhooks directly from your core API creates a tight coupling and a single point of failure:
- ❌ Downstream Downtime: If the receiver is down, your data is lost forever.
- ❌ Latency Spikes: Waiting for a slow webhook response ties up a thread and blocks your core API.
- ❌ Zombies: Failed events without observability are impossible to debug and replay.
Zyvan acts as a shock absorber. It separates Acceptance (Sync & Fast) from Delivery (Async & Reliable).
- 🛡️ Idempotent Ingestion: Never process the same event twice, even if your internal client aggressively retries the request during a network blip.
- 🔄 Intelligent Retries: Asynchronous BullMQ workers execute exponential backoff algorithms (with jitter) and configurable target-specific retry limits.
- 💀 Dead Letter Queue (DLQ): Poison messages and permanently failed events are automatically segregated for manual inspection and one-click bulk replay via the Dashboard.
- 🔐 HMAC Payload Signing: Every outbound delivery is signed (HMAC-SHA256) so the receiving server can verify the request's authenticity over the open internet.
- 🛡️ SSRF Prevention: Zyvan resolves DNS and blocks requests targeting internal IP ranges (e.g.,
localhost, AWS Metadata169.254.x.x). - 🔍 Full Visibility: Audit logs and a modern React (Next.js) dashboard expose the exact status code, latency, and response body of every single delivery attempt.
A clean, modern Monorepo structure containing separate stacks for the backend API and frontend Dashboard.
zyvan/
├── client/ # Dashboard UI (Next.js, Tailwind CSS, Recharts)
├── server/ # Core Reliability Engine (Node.js, Express, BullMQ, Prisma)
├── docs/ # Diagrams & Documentation
│ └── interview/ # 🎯 Interview Prep Docs (Resume points, ER Diagrams, Q&A)
├── docker-compose.yml
└── README.md
Looking to understand the system design in-depth for an interview or technical presentation?
- System Architecture & Data Model Flows: View the system ER Diagrams and Sequence Flows.
- Interview Q&A: 20 Advanced technical questions analyzing the scale and logic of this engine.
- Technical Buzzwords: A cheat-sheet of distributed system jargon (Idempotency, Backoff, SSRF) used here.
- Engine: Node.js v20 + Express (TypeScript)
- Infrastructure: PostgreSQL 15 (Persistence) & Redis 7 (Queueing)
- Task Scheduling: BullMQ (Job dispatching & delays)
- Database ORM: Prisma ORM
- Frontend Dashboard: Next.js 15 (App Router), React, Tailwind CSS
*(Note: The raw Express Ingestion API runs mapped to `http://localhost:3000`)*
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## 📄 License
Distributed under the MIT License. Built for mission-critical webhooks.