FormSDK - Zero-Lock-In Form Management

Framework-agnostic form state management with server-side validation.

Why FormSDK?

Stop rewriting form boilerplate.

Every project needs forms. Every project writes the same thing:

• Loading states
• Error handling
• Validation
• Request cancellation
• Reset logic

FormSDK gives you a consistent API across frameworks without locking you into a specific database or hosting provider.

vs. Writing your own:

• No need to handle navigator.sendBeacon for keepalive
• Automatic request deduplication (no double-submit)
• Unified error format across your entire app
• Captcha support built-in (Turnstile)
• Fewer lines of code to maintain

vs. Other form libraries:

• No component library - brings your own UI
• Works with any database via adapters
• Framework-agnostic (React, Svelte, Astro, Solid)
• Tiny bundle (~3KB for useForm hook)

Features

Client-Side

• useForm hook for React form state
• Field registration with register()
• Built-in validation (custom validator functions)
• Status tracking (idle, loading, success, error)
• Field-level errors and error clearing
• Form reset with reset()
• Request deduplication
• Keepalive via navigator.sendBeacon

Server-Side

• handleRequest for validation
• Custom field validators
• Cloudflare Turnstile captcha support
• IP and header context passing

Database Adapters

• PostgreSQL, Supabase, Neon, Turso
• Drizzle ORM, Prisma, Better Auth

Bundle Size

• ~3KB gzipped (useForm)
• ~10KB gzipped (handleRequest + adapters)

Quick Start

// Client
import { useForm } from "@formsdk/react";

const { register, handleSubmit, formState: { errors } } = useForm({
  action: "/api/contact",
});

// Server
import { handleRequest } from "@formsdk/core";

const result = await handleRequest({
  config: {
    fields: {
      email: (v) => typeof v === "string" && v.includes("@"),
    },
  },
  body: await req.json(),
});

License

MIT