Firefly

A minimal F# web framework built on Kestrel.

Firefly is part of a cohesive F# ecosystem:

• Firefly — Web framework (routing, middleware, DI, gRPC)
• Flame — Schema validation (parsing, rules, JSON Schema)
• Flare — HTTP client (typed requests, resilience)
• Evlog — Structured logging
• Rhinox — Database conventions

Quick Start

dotnet new fire -n MyApp
cd MyApp
firefly dev

Features

• Type-safe routing with format strings (%i, %s, %b, %f)
• Auto dependency injection
• Schema validation via Flame
• 15+ built-in middleware (CORS, JWT, rate limiting, compression, etc.)
• WebSocket and SSE support
• gRPC server with computation expressions
• File uploads and downloads
• Pagination, versioning, HATEOAS, bulk operations
• OpenTelemetry traces and metrics
• Response caching with ETag auto-generation
• Typed configuration from .env files
• Testing helpers (direct + integration modes)
• CLI generators (controllers, schemas, Docker)