Install

Install the seampact command from npm and start a project. This page is for a Node.js app. For Spring Boot, Laravel, Symfony or Python, go to install in other ecosystems; commands per stack shows how each runs the commands.

You need Node.js 24 or later and npm.

Create the folder

mkdir notes-app
cd notes-app
npm init -y
npm pkg set type=module

Install seampact

npm install --save-dev @seampact/cli

This is the seampact command. The generators and the runtime of your server or client come with its guide, in Your first API for a server: the package map lists them all.

Keep every @seampact/* package at the same version.

pnpm and Yarn take the same package names. pnpm holds back a package published in the last day: if it finds none, wait or add minimumReleaseAgeExclude: ["@seampact/*"] to pnpm-workspace.yaml. Yarn Plug’n’Play is not supported.

Start the project

npx seampact init

You see Created .gitignore. among the lines. init writes:

• seampact.config.yaml, the config;
• contract/api.yaml, a small example contract;
• contract/.seampact/schemas, the schemas your editor reads to check the contract;
• .seampact/ in .gitignore.

npx seampact init --blank writes the api header alone instead of the example.

Next: your first API