Alternative Payments Invoicing

Alternative Payments Invoicing

Overview

Invoices are the billing records in Alternative Payments. Each invoice belongs to a customer, carries one or more line items, and has a due date. Once an invoice exists you can fetch a hosted payment link (a URL the customer visits to pay) and a PDF link (a signed download of the invoice document).

Separately, payment requests are standalone hosted payment links that are not tied to a stored invoice — useful for ad-hoc charges and follow-ups.

The key posture: hosted payment links and payment requests let the customer choose to pay. Generating a link does not charge a card or move money — it simply produces a URL. This integration never executes a direct charge. See Alternative Payments API Patterns for why POST /payments (direct charge) is excluded by design.

Core Concepts

Invoice Status

Status	Description	Payable
open	Issued and awaiting payment	Yes
paid	Fully paid	No
overdue	Past due_date and still unpaid	Yes
archived	Removed from default lists (destructive)	No

Archiving uses DELETE /invoices/{id} and is destructive — confirm before running.

Hosted Links vs. Direct Charges

Mechanism	What it does	Money movement
Payment link (GET /invoices/{id}/payment-link)	URL for an existing invoice	Customer pays — not the integration
Payment request (POST /payments/request)	Standalone hosted link	Customer pays — not the integration
Direct charge (POST /payments)	Charges a card/bank	Not exposed

Field Reference

Invoice Fields

Field	Type	Required	Description
id	string	System	Auto-generated unique identifier
customer_id	string	Yes	Customer the invoice belongs to
currency	string	Yes	ISO currency code (e.g. USD)
due_date	string	Yes	Payment due date (YYYY-MM-DD)
line_items	array	Yes	One or more line items (see below)
reference	string	No	Reference text (PO number, billing period)
status	string	Read-only	open, paid, overdue, archived
amount_due	number	Read-only	Remaining unpaid amount
created_at	datetime	Read-only	Creation timestamp

Line Item Fields

Field	Type	Required	Description
description	string	Yes	Line item description
quantity	number	Yes	Quantity
unit_amount	number	Yes	Price per unit

Payment Request Fields

Field	Type	Required	Description
amount	number	Yes	Amount to request
currency	string	Yes	ISO currency code (e.g. USD)
redirect_url	string	Yes	Where to send the customer after paying
reference_id	string	No	Your reference for reconciliation

API Patterns

All requests carry a bearer token (Authorization: Bearer <token>). See Alternative Payments API Patterns for the OAuth2 token flow, the 5 req/sec rate limit, and cursor pagination.

List Invoices

curl -s "https://public-api.alternativepayments.io/invoices?limit=100" \
  -H "Authorization: Bearer ${TOKEN}"

Responses are cursor-paginated — items in data[], with next_cursor / has_more. Pass after=<cursor> for the next page.

Get a Single Invoice

curl -s "https://public-api.alternativepayments.io/invoices/${INVOICE_ID}" \
  -H "Authorization: Bearer ${TOKEN}"

Create an Invoice

Required: customer_id, currency, due_date, and a non-empty line_items[].

curl -s -X POST "https://public-api.alternativepayments.io/invoices" \
  -H "Authorization: Bearer ${TOKEN}" \
  -H "Content-Type: application/json" \
  -d '{
    "customer_id": "'${CUSTOMER_ID}'",
    "currency": "USD",
    "due_date": "2026-07-05",
    "reference": "June 2026 Managed Services",
    "line_items": [
      {
        "description": "Monthly Managed Services - Acme Corp (25 endpoints)",
        "quantity": 1,
        "unit_amount": 2500.00
      },
      {
        "description": "Microsoft 365 Business Premium (25 users)",
        "quantity": 25,
        "unit_amount": 22.00
      }
    ]
  }'

Get a Hosted Payment Link

Returns a URL the customer visits to pay the invoice. No charge occurs until the customer completes payment.

curl -s "https://public-api.alternativepayments.io/invoices/${INVOICE_ID}/payment-link" \
  -H "Authorization: Bearer ${TOKEN}"

Get a Signed PDF Link

curl -s "https://public-api.alternativepayments.io/invoices/${INVOICE_ID}/pdf-link" \
  -H "Authorization: Bearer ${TOKEN}"

Archive an Invoice (Destructive — Confirm First)

DELETE /invoices/{id} archives the invoice. Confirm with the operator before running it.

curl -s -X DELETE "https://public-api.alternativepayments.io/invoices/${INVOICE_ID}" \
  -H "Authorization: Bearer ${TOKEN}"

A 204 No Content indicates success.

Create a Hosted Payment Request

A standalone hosted link, not tied to a stored invoice. Required: amount, currency, redirect_url. The response includes a hosted URL — the customer chooses to pay; the integration does not charge them.

curl -s -X POST "https://public-api.alternativepayments.io/payments/request" \
  -H "Authorization: Bearer ${TOKEN}" \
  -H "Content-Type: application/json" \
  -d '{
    "amount": 2500.00,
    "currency": "USD",
    "redirect_url": "https://portal.example-msp.com/thanks",
    "reference_id": "MS-2026-06-ACME"
  }'

Get a Payment Request

curl -s "https://public-api.alternativepayments.io/payments/request/${REQUEST_ID}" \
  -H "Authorization: Bearer ${TOKEN}"

JavaScript Example

async function createInvoiceWithLink(token, invoice) {
  const base = 'https://public-api.alternativepayments.io';
  const headers = {
    'Authorization': `Bearer ${token}`,
    'Content-Type': 'application/json'
  };

  const createRes = await fetch(`${base}/invoices`, {
    method: 'POST', headers, body: JSON.stringify(invoice)
  });
  const createText = await createRes.text();
  if (!createRes.ok) throw new Error(`Create invoice failed (${createRes.status}): ${createText}`);
  const created = JSON.parse(createText);

  // Fetch a hosted link the customer can use to pay — no charge happens here.
  const linkRes = await fetch(`${base}/invoices/${created.id}/payment-link`, {
    headers: { 'Authorization': `Bearer ${token}` }
  });
  const link = JSON.parse(await linkRes.text());
  return { invoice: created, paymentLink: link };
}

Common Workflows

Monthly MSP Billing Cycle

1. Create invoices for each managed services customer with their line items
2. Generate hosted payment links and email them to the customer's users
3. Track payment via read-only transactions (see Payments & Payouts)
4. Follow up on overdue invoices with a fresh payment link

Ad-hoc Charge Follow-up

When chasing an outstanding balance that isn't a formal invoice, create a payment request with the amount, currency, and a redirect_url, then send the hosted link. The customer pays at their discretion.

Error Handling

Code	Meaning	Action
201	Invoice / payment request created	Process response
204	Archived	Treat as success
400 / 422	Validation error	Inspect the errors array; fix the request
401	Unauthorized	Refresh token, retry once
404	Invoice / request not found	Verify the id
429	Rate limited	Back off (Retry-After), retry

Common validation causes: empty line_items[], missing due_date, an unknown customer_id, or a missing redirect_url on a payment request.

Best Practices

1. Always include line items — line_items[] must be non-empty.
2. Use clear references — include the billing period and service in reference.
3. Send hosted links, not charges — let the customer pay via the payment link.
4. Set a reference_id on payment requests — makes reconciliation clean.
5. Confirm before archiving — DELETE is destructive.
6. Read bodies as text then parse — avoids "body already read" errors.

Endpoint Reference

Endpoint	Method	Description
/invoices	GET	List invoices (cursor-paginated)
/invoices	POST	Create an invoice with line items
/invoices/{id}	GET	Get a single invoice
/invoices/{id}	DELETE	Archive an invoice (destructive)
/invoices/{id}/payment-link	GET	Hosted payment link for the invoice
/invoices/{id}/pdf-link	GET	Signed PDF download link
/payments/request	POST	Create a hosted payment request
/payments/request/{id}	GET	Get a payment request

Related Skills

• Alternative Payments API Patterns - Auth, pagination, rate limits
• Alternative Payments Customers - Customers and their users
• Alternative Payments Payments & Payouts - Read-only transactions and payouts