Building a webhook relay infrastructure with ASP.NET Core 8 and React 19 I'm excited to announce WebhookRelay — a self-hosted, open-source webhook management platform built specifically for the (beta) .NET ecosystem. After years of working with webhook integrations and seeing the limitations of existing solutions, I set out to create a modern, alternative that leverages the latest .NET technologies while providing complete control and flexibility. Webhooks are the backbone of modern integrations, but managing them at scale presents several challenges: Signature Verification: Each provider (Stripe, GitHub, Twilio) uses different HMAC algorithms Reliability: Network failures require intelligent retry mechanisms Observability: Debugging failed webhooks can be time-consuming Multi-System Coordination: Fan-out to multiple targets with routing rules Vendor Lock-in: Commercial solutions can be expensive and inflexible WebhookRelay addresses these challenges with a comprehensive feature set: ✅ Multi-Provider Ingestion Stripe: Automatic signature verification via Stripe-Signature header GitHub: X-Hub-Signature-256 verification out of the box Twilio: Built-in support for Twilio webhooks Generic: Custom HMAC-SHA256 verification for any provider ✅ Security First Constant-time HMAC comparison to prevent timing attacks Complete audit log of all inbound requests (including rejected events) Per-endpoint secret management ✅ Intelligent Delivery Fan-out: Forward one webhook to multiple target URLs simultaneously Routing Rules: JSON path conditions (equals, contains, starts_with, exists, etc.) Automatic Retries: Exponential backoff with configurable max attempts Dead-letter Queue: Failed events stored for manual inspection ✅ Event Management Duplicate Detection: Provider event IDs deduplicated per endpoint Event Replay: Re-deliver any stored event on demand Real-time Dashboard: Live updates via SignalR with syntax-highlighted payloads WebhookRelay leverages cutting-edge .NET and frontend technologies: ASP.NET Core 8 Web API Entity Framework Core 8 for data access System.Threading.Channels for high-performance in-process queuing Serilog for structured logging React 19 with Vite 8 TypeScript for type safety shadcn/ui + Tailwind CSS for modern UI TanStack Query v5 for server state management React Router v7 for navigation React Hook Form + Zod for forms ASP.NET Core SignalR for live dashboard updates WebSocket connections for instant event notifications WebhookRelay.sln ├── src/ │ ├── WebhookRelay.Api/ # ASP.NET Core Web API + background workers │ ├── WebhookRelay.Core/ # Domain entities, interfaces (no external deps) │ ├── WebhookRelay.Infrastructure/ # EF Core, HTTP delivery, verifiers │ └── WebhookRelay.Shared/ # DTOs shared between API and frontend ├── dashboard/ # React 19 frontend ├── tests/ # Comprehensive test suite └── deploy/ # Docker Compose deployment Ingest: Webhook received at /webhooks/:endpointId Verify: HMAC signature validation per provider Store: Event persisted to database with full payload Route: Apply routing rules to determine target endpoints Deliver: Fan-out to multiple targets with retry logic Monitor: Real-time dashboard updates via SignalR .NET 8 SDK Node.js 22+ # Clone the repository git clone https://github.com/vrbagal/webhook-relay.git cd webhook-relay # Start the API (uses SQLite by default) cd src/WebhookRelay.Api dotnet run # API available at https://localhost:5001 # Start the dashboard cd dashboard npm install npm run dev # Dashboard available at http://localhost:3000 The project supports multiple databases out of the box: SQLite (Default - Zero Config) { "DatabaseProvider": "Sqlite", "ConnectionStrings": { "DefaultConnection": "Data Source=webhookrelay.db" } } SQL Server { "DatabaseProvider": "SqlServer", "ConnectionStrings": { "DefaultConnection": "Server=localhost;Database=WebhookRelay;Trusted_Connection=True;" } } PostgreSQL { "DatabaseProvider": "PostgreSQL", "ConnectionStrings": { "DefaultConnection": "Host=localhost;Database=webhookrelay;Username=postgres;Password=yourpassword" } } cd deploy docker compose up --build Services started: api: ASP.NET Core API on port 5000 dashboard: React app served via nginx on port 80 db: SQL Server 2022 (when using SqlServer profile) # Compute signature SECRET="your-signing-secret" PAYLOAD='{"event":"payment.completed","amount":100}' SIG=$(echo -n "$PAYLOAD" | openssl dgst -sha256 -hmac "$SECRET" | awk '{print $2}') # Send webhook curl -X POST https://localhost:5001/webhooks/ \ -H "Content-Type: application/json" \ -H "x-webhook-signature: sha256=$SIG" \ -H "x-webhook-event: payment.completed" \ -H "x-webhook-id: evt-$(date +%s)" \ -d "$PAYLOAD" Stripe: Just send the original Stripe webhook — it's automatically verified GitHub: Send as-is — the X-Hub-Signature-256 header is verified automatically Method Path Description GET /api/endpoints List all endpoints POST /api/endpoints Create endpoint GET /api/endpoints/:id Get endpoint details PUT /api/endpoints/:id Update endpoint DELETE /api/endpoints/:id Delete endpoint Method Path Description POST /api/endpoints/:id/targets Add delivery target DELETE /api/endpoints/:id/targets/:targetId Remove target Method Path Description GET /api/events List events (paginated, filterable) GET /api/events/:id Get event with delivery attempts POST /api/events/:id/replay Replay event // Stripe webhook handler with routing rules { "endpoint": "stripe-payments", "targets": [ { "url": "https://api.myapp.com/payments", "rules": [{ "path": "$.type", "operator": "equals", "value": "payment_intent.succeeded" }] }, { "url": "https://analytics.myapp.com/events", "rules": [{ "path": "$.type", "operator": "contains", "value": "payment" }] } ] } // GitHub webhook fan-out for CI/CD { "endpoint": "github-repo", "targets": [ { "url": "https://ci.example.com/webhook" }, { "url": "https://notifications.example.com/github" }, { "url": "https://analytics.example.com/events" } ] } CRM Integration: Forward webhooks to Salesforce, HubSpot, and custom systems Notification Systems: Send to Slack, email, and SMS simultaneously Analytics: Route events to multiple analytics platforms The React dashboard provides comprehensive webhook management: Real-time Monitoring: Live updates via SignalR Payload Inspection: Syntax-highlighted JSON viewing Event Replay: One-click re-delivery of failed events Endpoint Management: Create, update, delete endpoints and targets Routing Rules: Visual rule builder with JSON path support Delivery Analytics: Success/failure rates and retry statistics WebhookRelay uses System.Threading.Channels for high-performance, in-process queueing: Zero external dependencies Excellent performance characteristics Built-in backpressure handling SQLite: Perfect for development and small deployments SQL Server: Enterprise-grade with full transaction support PostgreSQL: Open-source with advanced features Self-hosted: Complete control on your infrastructure Docker: Easy containerization and orchestration Cloud: Deploy to Azure, AWS, or any cloud provider Each provider's signature algorithm is implemented exactly: Stripe: Stripe-Signature header with timestamp and signature GitHub: X-Hub-Signature-256 with HMAC-SHA256 Generic: Custom x-webhook-signature header All signature verifications use constant-time comparison to prevent timing attacks. Per-endpoint secret configuration Environment variable support Azure Key Vault integration ready Core business logic Signature verification algorithms Routing rule evaluation API endpoints with WebApplicationFactory Database operations External HTTP delivery Full webhook flow from ingestion to delivery Dashboard functionality Docker deployment [ ] Enhanced documentation with tutorials [ ] SDK for popular languages (Python, Node.js, Go) [ ] Plugin system for custom providers [ ] Advanced analytics and reporting [ ] Multi-tenancy support [ ] Webhook transformation (modify payload before delivery) [ ] Advanced routing with regex support [ ] Rate limiting per endpoint [ ] Managed cloud service option [ ] Marketplace for pre-built integrations [ ] Enterprise features (SSO, audit logs, SLA) [ ] Machine learning for anomaly detection WebhookRelay is an open-source project and welcomes contributions: Fork the repository Create a feature branch (git checkout -b feature/amazing-feature) Commit your changes (git commit -m 'Add amazing feature') Push to the branch (git push origin feature/amazing-feature) Open a Pull Request Documentation: Tutorials, API docs, deployment guides Testing: Unit tests, integration tests, E2E tests Features: New providers, advanced routing, analytics UI/UX: Dashboard improvements, accessibility WebhookRelay represents a modern approach to webhook management, built from the ground up for .NET developers who want complete control over their integration infrastructure. Whether you're building a multi-tenant SaaS application, integrating multiple payment providers, or coordinating complex business workflows, WebhookRelay provides the foundation you need. Modern Stack: ASP.NET Core 8, React 19, latest technologies Self-Hosted: Complete control without vendor lock-in Open Source: MIT license, community-driven development Try it out: Clone the repo and run locally Star the project: Show support on GitHub Contribute: Help build the future of webhook management Share: Spread the word in .NET communities Ready to get started? Visit the GitHub repository and start managing your webhooks like a pro! For more .NET development content, follow me on LinkedIn. Built with ❤️ by Vikrant Bagal