From zero to signed PDF in five minutes

# Create a contract from a template
curl -X POST https://fastcontracts.com/api/v1/contracts \
  -H "Authorization: Bearer $FC_API_KEY" \
  -H "Content-Type: application/json" \
  -H "Idempotency-Key: $(uuidgen)" \
  -d '{
    "template_id": "nda",
    "title": "NDA with Acme Corp",
    "client_name": "Acme Corp",
    "client_email": "[email protected]",
    "jurisdiction": "CA",
    "form_data": {
      "disclosingParty": "FastContracts Inc",
      "receivingParty": "Acme Corp"
    }
  }'

// app/api/fastcontracts-webhook/route.ts
import { createHmac, timingSafeEqual } from 'crypto'
import { NextRequest, NextResponse } from 'next/server'

const WEBHOOK_SECRET = process.env.FC_WEBHOOK_SECRET!

export async function POST(request: NextRequest) {
  const rawBody = await request.text()
  const signature = request.headers.get('x-fc-signature') ?? ''

  const expected = createHmac('sha256', WEBHOOK_SECRET)
    .update(rawBody)
    .digest('hex')

  const valid =
    signature.length === expected.length &&
    timingSafeEqual(Buffer.from(signature), Buffer.from(expected))

  if (!valid) {
    return NextResponse.json({ error: 'bad signature' }, { status: 401 })
  }

  const event = JSON.parse(rawBody)
  // Respond fast — queue any heavy work for a worker
  switch (event.type) {
    case 'contract.completed':
      console.log('Completed:', event.data.contract_id, event.data.pdf_url)
      break
    case 'signature.signed':
      console.log(event.data.party_email, 'signed')
      break
  }

  return NextResponse.json({ received: true })
}