curl -X PATCH https://invoice.horizonpay.co/api/v1/customers/cus_Nf3kQ8pR2mX7vB1cT9wL4sZ6 \
  -H "Authorization: Bearer $INVOICE_AI_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{ "phone": "+1 512 555 0100" }'

import InvoiceAI from '@horizonpay/invoice-ai'

const invoiceai = new InvoiceAI() // reads INVOICE_AI_API_KEY

const customer = await invoiceai.customers.update('cus_Nf3kQ8pR2mX7vB1cT9wL4sZ6', {
  phone: '+1 512 555 0100',
})
console.log(customer.phone)

from invoice_ai import InvoiceAI

client = InvoiceAI()  # reads INVOICE_AI_API_KEY

customer = client.customers.update(
    "cus_Nf3kQ8pR2mX7vB1cT9wL4sZ6",
    phone="+1 512 555 0100",
)
print(customer.phone)

{
  "data": {
    "id": "cus_Nf3kQ8pR2mX7vB1cT9wL4sZ6",
    "object": "customer",
    "name": "Acme Industries",
    "email": "[email protected]",
    "phone": "+1 512 555 0100",
    "tax_id": "US-EIN 12-3456789",
    "address": {
      "line1": "4th Floor, Market Tower",
      "line2": null,
      "city": "Austin",
      "state": "TX",
      "postal_code": "73301",
      "country": "US"
    },
    "deleted": false,
    "created": "2026-09-22T09:30:00.000Z"
  }
}

{
  "type": "https://invoice.horizonpay.co/problems/unauthorized",
  "title": "Unauthorized",
  "status": 401,
  "detail": "Send your API key as `Authorization: Bearer inv_live_…`.",
  "instance": "req_7f3c9a1e2b4d4e8a9c6f2d1b0a3e5f71",
  "code": "unauthorized"
}

{
  "type": "https://invoice.horizonpay.co/problems/forbidden",
  "title": "Insufficient scope",
  "status": 403,
  "detail": "This credential is missing the invoices:write scope.",
  "instance": "req_7f3c9a1e2b4d4e8a9c6f2d1b0a3e5f71",
  "code": "forbidden"
}

{
  "type": "https://invoice.horizonpay.co/problems/not-found",
  "title": "Not found",
  "status": 404,
  "detail": "Client not found.",
  "instance": "req_7f3c9a1e2b4d4e8a9c6f2d1b0a3e5f71",
  "code": "not_found"
}

{
  "type": "https://invoice.horizonpay.co/problems/validation",
  "title": "Validation failed",
  "status": 422,
  "detail": "Some fields need attention.",
  "instance": "req_7f3c9a1e2b4d4e8a9c6f2d1b0a3e5f71",
  "code": "validation",
  "errors": [
    {
      "path": "name",
      "message": "Enter your customer's name"
    }
  ]
}

{
  "type": "https://invoice.horizonpay.co/problems/rate-limited",
  "title": "Too many requests",
  "status": 429,
  "detail": "Rate limit of 120 per 60s exceeded.",
  "instance": "req_7f3c9a1e2b4d4e8a9c6f2d1b0a3e5f71",
  "code": "rate_limited"
}