@seamstack/cli

The seam command — dev, build, plan, and start any SeamStack project.

pnpm add -D @seamstack/cli

If you scaffolded with pnpm create seam@latest, this is already a dev dependency.

The seam binary

seam dev    [-v|--verbose] [--host <host>]
seam build  [-v|--verbose] [--host <host>]
seam start  [-v|--verbose] [--host <host>]
seam plan   [phase] [--json] [-v|--verbose] [--host <host>]

• seam dev — Boot the dev composition: one URL, frontend hot-reloads, backend handles /api.
• seam build — Run the frontend's build and write a manifest the backend can find.
• seam start — Run the production composition. The backend serves API routes and the built frontend on the same port.
• seam plan [dev|build|start] — Print the topology the seam resolved for a phase. --json for the machine-readable form. Useful for debugging "why is my backend on a different port than I expected."
• --host <host> — Bind the public-facing server. Defaults to localhost. --host 0.0.0.0 exposes to the LAN.
• -v, --verbose — Show internal seam details (resolved private ports, debug events). Quiet by default.

defineWeave

defineWeave is the typed config helper for seam.config.ts:

import { defineWeave } from '@seamstack/cli'
import vite from '@seamstack/vite/adapter'
import hono from '@seamstack/hono/adapter'

export default defineWeave({
  fabric: [vite({ root: './client' }), hono({ entry: './server/index.ts' })],
  port: 4567,
})

fabric is the array of adapters — typically one frontend (vite/astro/angular) and one backend (hono/express/fastify/elysia/nestjs), in any order. The seam wires them together. port is the public-facing port.

More

See the SeamStack README for the bigger picture, the mix-and-match support table, and the philosophy.