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Introduction to Pikku

Pikku is a TypeScript backend that adapts. Write your business logic once as plain functions. Wire them to any protocol — HTTP, WebSockets, queues, scheduled tasks, CLI, or AI agent tools — without changing a line of that logic.

Define once. Run anywhere. No lock-in. Just TypeScript.

The Problem​

Traditional backend frameworks lock you into choices before you've written a line of business logic:

  • Express/Fastify — Great for servers, but bundling the whole framework into a serverless function is wasteful
  • AWS Lambda — Great for isolated functions, but fragments your logic across services
  • NestJS — Heavy runtime with decorator-based patterns that make tree-shaking and portability hard

The result: you're forced to choose your architecture upfront. Want to move a hot path to serverless? Extract a microservice? Add a background queue? That's a rewrite, not a config change.

Types drift. Logic fragments. Vendor lock-in creeps in.

The Pikku Answer​

Architecture becomes a deployment decision, not a coding decision.

Write your function once:

export const sendWelcomeEmail = pikkuFunc<SendWelcomeEmailInput>(
  async ({ email }, data) => {
    await email.send({ to: data.userEmail, subject: 'Welcome!', body: `Hello ${data.userName}!` })
    return { sent: true }
  }
)

Wire it to whatever you need:

// Process from a background queue
wireQueueWorker({ queue: 'emails', func: sendWelcomeEmail })

// Or trigger on a schedule
wireScheduler({ schedule: '0 9 * * *', func: sendDailyDigest })

Same business logic. Different entry points. Zero duplication.

What's in This Section​

  • Vision — The three principles that shape how Pikku is built
  • Architecture — How functions, wiring, and the CLI fit together
  • Types & Schemas — How TypeScript types drive validation, clients, and docs automatically
  • Typed Clients — The generated clients that make end-to-end type safety real
  • Limitations — Where Pikku is deliberately scoped, and what it doesn't do

Ready to build? Start with Getting Started.