SDK Kit

A blueprint for building JavaScript SDKs

SDK Kit provides a composable, plugin-based architecture for building type-safe, tree-shakeable JavaScript SDKs. Built with TypeScript and designed for modern development workflows, it offers the flexibility of a minimal core with the power of capability-based plugins. Whether you’re shipping a client library for your API, building a browser SDK for your product, or learning how modern SDKs work—SDK Kit gives you the patterns to create something production-ready.

Why SDK Kit?

Building a JavaScript SDK from scratch is hard. You need to figure out architecture, plugin systems, configuration management, events, storage, and more. SDK Kit gives you a proven blueprint:

• Functional Plugins - Pure functions with explicit dependencies, no classes or hidden state
• Event-Driven Coordination - Plugins communicate through events with wildcard patterns
• Type-Safe - Full TypeScript support throughout
• Tree-Shakeable - Users only bundle what they use
• Battle-Tested Patterns - Architecture proven in production SDKs
• Essential Building Blocks - 6 plugins covering storage, context, transport, queuing, polling, and consent
• Learn by Building - Understand how modern SDKs work by creating your own

Quick Start

Build your first SDK in minutes:

npm install @prosdevlab/sdk-kit @prosdevlab/sdk-kit-plugins

import { SDK } from '@prosdevlab/sdk-kit'
import { storagePlugin, contextPlugin, transportPlugin } from '@prosdevlab/sdk-kit-plugins'
 
// Build your SDK from composable plugins
const mySDK = new SDK()
mySDK.use(storagePlugin)
mySDK.use(contextPlugin)
mySDK.use(transportPlugin)
 
await mySDK.init({
  storage: { namespace: 'mycompany' },
  transport: { endpoint: 'https://api.mycompany.com' }
})

// Your SDK is ready to use
mySDK.storage.set('userId', '123')
const context = mySDK.context.get()
 
await mySDK.transport.send({
  event: 'pageview',
  context
})
 
// Export and publish to npm for your users
export default mySDK

Project Status

Core Framework:

• Core SDK with plugin system
• 6 capabilities (Emitter, Config, Namespace, Expose, Requirer, Extensible)
• Plugin-to-plugin communication via hold()
• 219 tests with >90% coverage
• Full TypeScript support

Essential Plugins:

• Storage (localStorage/sessionStorage/cookies/memory)
• Context (browser/device detection)
• Poll (async resource polling)
• Queue (batching & persistence)
• Transport (fetch/beacon/pixel/XHR)
• Consent (OneTrust/CookieBot)
• Logging (Pino with privacy-first design)

Learn More

• Getting Started - Build your first SDK
• Core Concepts - Understand the architecture
• Plugin Guide - Create custom plugins
• Plugin Extensibility - Plugin-to-plugin capabilities (Phase 3)