F# + Giraffe

F# + Giraffe for functional APIs.

BackendComplex

Stack Components

LanguageF# 9

FrameworkGiraffe 6

ORMEF Core 9

DBPostgreSQL 16

Why

Functional, type-safe, ASP.NET Core based. Node.js, Go, and Python are the top 3 backend languages (Stack Overflow 2024).

Go's goroutines handle 100k+ concurrent connections per process; Node's event loop excels at I/O-bound workloads.

When

Use for F# web apps. Avoid for OOP style.

How

1. dotnet new giraffe 2. Define routes with choose 3. Configure webHost 4. dotnet run 5. Add environment configuration — cp .env.example .env && edit values 6. Run tests — npm test or pnpm test to verify setup 7. Deploy — git push to trigger CI/CD or manual deploy

Example

let webApp = choose [ GET >=> route '/users' >=> json users ] // F# + Giraffe — usage example import { FGiraffe } from "fsharp-giraffe"; const result = await fgiraffe({ input: "data" }); console.log(result);

Common Problems

⚠Computation expressions — use task {} for async
⚠Routing — use choose and route
⚠Configuration drift between environments — use infrastructure-as-code (Terraform/Pulumi) to keep dev/staging/prod identical

Best Practices

✓Use Giraffe ViewEngine for HTML
✓Leverage F# type providers
✓Set up health checks and graceful shutdown — handle SIGTERM to drain in-flight requests before exit

FAQ

What is F# + Giraffe and what projects is it for?

F# + Giraffe for functional APIs. It pairs layered technologies for end-to-end type safety and out-of-the-box deploys, fitting everything from MVPs to production SaaS.

How do I spin up a working demo with F# + Giraffe in 10 minutes?

Two steps: (1) dotnet new giraffe; (2) Define routes with choose. Get the local dev server running, then wire one real data source to verify the end-to-end loop.

What is the most common pitfall with F# + Giraffe and how do I avoid it?

The most common pitfall is: Computation expressions — use task {} for async. Avoid it by adding the matching checklist to your PR template and running type-check + lint + unit tests in CI — three gates before merge.

What are the best practices for F# + Giraffe?

Best practices for F# + Giraffe include: Use Giraffe ViewEngine for HTML; Leverage F# type providers; Set up health checks and graceful shutdown — handle SIGTERM to drain in-flight requests before exit. The first one — "Use Giraffe ViewEngine for HTML" — should be set up at project init to avoid costly rework later.

When should I NOT choose F# + Giraffe?

Pick something else in three cases: (1) the team has zero experience with the core framework and the deadline is tight (learning-curve risk); (2) it's a pure content/marketing site (Astro is lighter); (3) you need very high throughput (>10k RPS) or strict-consistency microservices (Go/Rust). F# + Giraffe shines for mid-to-high complexity full-stack and API work — don't over-engineer simple static pages with it.