contract-kit

Contract and client entrypoint for incremental Contract Kit adoption.

contract-kit gives existing apps the first Contract Kit boundary: define contracts and call them from a typed client before adding the server runtime, use cases, ports, and providers.

What's included

This package re-exports:

• @contract-kit/core - Contract definitions and builders
• @contract-kit/client - HTTP client for contract-based requests

What's not included

Install these separately when you need them:

• OpenAPI - @contract-kit/openapi
• Application layer - @contract-kit/application
• Domain modeling - @contract-kit/domain
• Error/catalog utilities - @contract-kit/errors
• Ports/providers - @contract-kit/ports and @contract-kit/provider-*
• Mail - @contract-kit/mail
• Server runtime/adapters - @contract-kit/server, @contract-kit/next
• Devtools - @contract-kit/devtools
• React integrations - @contract-kit/react-query, @contract-kit/react-hook-form, @contract-kit/nuqs

Installation

npm install contract-kit
npm install zod  # or valibot, arktype, etc.

Add optional packages as needed:

npm install @contract-kit/openapi zod
npm install @contract-kit/next @contract-kit/ports next
npm install @contract-kit/mail
npm install @contract-kit/devtools
npm install @contract-kit/react-query @tanstack/react-query react
npm install @contract-kit/react-hook-form react-hook-form @hookform/resolvers
npm install @contract-kit/nuqs @contract-kit/react-query nuqs @tanstack/react-query react

Quick start

import { createContractGroup, createClient } from "contract-kit";
import { z } from "zod";

// Define a contract
const todos = createContractGroup()
  .namespace("todos")
  .prefix("/api/todos");

export const getTodo = todos
  .get("/:id")
  .pathParams(z.object({ id: z.string() }))
  .responses({ 200: z.object({
    id: z.string(),
    title: z.string(),
    completed: z.boolean(),
  }) });

// Create a typed client
const client = createClient({
  baseUrl: "https://api.example.com",
});

// Make type-safe requests
const getTodoEndpoint = client.endpoint(getTodo);

const result = await getTodoEndpoint.call({
  path: { id: "123" },
});

Optional add-ons

OpenAPI

npm install @contract-kit/openapi zod

Server

npm install @contract-kit/next @contract-kit/ports next

React

npm install @contract-kit/react-query @tanstack/react-query react
npm install @contract-kit/react-hook-form react-hook-form @hookform/resolvers
npm install @contract-kit/nuqs @contract-kit/react-query nuqs @tanstack/react-query react

Documentation

For complete documentation, visit: https://contract-kit.dev

License

MIT