Integrate with SvelteKit

Install the Commet Skill so your coding agent can integrate the current SDK and verify its work against the live API contract.

npx skills add commet-labs/skills --skill commet

Install

pnpm
npm
yarn
bun

pnpm add @commet/node

npm install @commet/node

yarn add @commet/node

bun add @commet/node

Configure

.env

COMMET_API_KEY=ck_sandbox_xxx

src/lib/server/commet.ts

import { Commet } from '@commet/node'
import { COMMET_API_KEY } from '$env/static/private'

export const commet = new Commet({
  apiKey: COMMET_API_KEY,
})

customers.create is idempotent — if a customer with the same id already exists, it returns the existing record.

src/routes/api/billing/subscribe/+server.ts

import { json } from '@sveltejs/kit'
import { commet } from '$lib/server/commet'
import type { RequestHandler } from './$types'

export const POST: RequestHandler = async ({ request }) => {
  const { customerId, email } = await request.json()

  await commet.customers.create({ email, id: customerId })

  const subscription = await commet.subscriptions.create({
    customerId,
    planCode: 'pro',
  })

  return json({ checkoutUrl: subscription.checkoutUrl ?? null })
}

Check Access

src/routes/api/billing/access/[customerId]/+server.ts

import { json } from '@sveltejs/kit'
import { commet } from '$lib/server/commet'
import type { RequestHandler } from './$types'

export const GET: RequestHandler = async ({ params }) => {
  const subscription = await commet.subscriptions.getActive({ customerId: params.customerId })

  if (!subscription) {
    return json({ error: 'no_active_subscription' }, { status: 404 })
  }

  const feature = await commet.featureAccess.get({
    code: 'api_calls',
    customerId: params.customerId,
  })

  return json({ status: subscription.status, allowed: feature.allowed })
}

Track Usage

src/routes/api/billing/usage/+server.ts

import { json } from '@sveltejs/kit'
import { commet } from '$lib/server/commet'
import type { RequestHandler } from './$types'

export const POST: RequestHandler = async ({ request }) => {
  const { customerId } = await request.json()

  await commet.usage.track({
    customerId,
    featureCode: 'api_calls',
    value: 1,
  })

  return json({ tracked: true })
}

Usage is aggregated and billed at end of period.

Customer Portal

src/routes/api/billing/portal/+server.ts

import { redirect } from '@sveltejs/kit'
import { commet } from '$lib/server/commet'
import type { RequestHandler } from './$types'

export const GET: RequestHandler = async ({ locals }) => {
  const portal = await commet.portal.getUrl({
    customerId: locals.user.customerId,
  })

  redirect(303, portal.portalUrl)
}

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