Introduction to Invoicing

Paisr provides a full-stack billing system designed to manage the complete lifecycle from invoice creation to payment collection and settlement. Invoices support multiple currencies, up to 500 line items each, and integrate directly with your customer records for clean reporting and reconciliation.

Creating an Invoice

Navigate to Billing → Invoices in your dashboard and click Create Invoice, or use the Invoices API.

1. Set the details — add a summary describing what the invoice is for, select the customer, set the currency, and choose a due date using relative time (e.g. In 7 days or In 30 days).
2. Add line items — each line item needs a description, a unit price of at least 0.01, and a quantity of at least 1. You can add up to 500 line items per invoice.
3. Create invoice — click Create to generate the invoice and its checkout session.

curl -X POST "https://api.live.paisr.tech/v2/invoices" \
  -H "Authorization: Bearer <token>" \
  -H "User-Agent: MyApp/1.0" \
  -H "Content-Type: application/json" \
  -d '{
  "customer": "cus_<id>",
  "summary": "Website redesign - Q3 2025",
  "currency": "SRD",
  "due": "In 14 days",
  "line_items": [
    { "description": "Design", "unit_price": 500.00, "quantity": 1 },
    { "description": "Development", "unit_price": 750.00, "quantity": 2 }
  ]
}'

The response includes the invoice ID and a session.url for the hosted checkout link of this invoice.

Sending an Invoice

Once created, share the checkout URL with the customer directly, or send it by email from the dashboard. The email delivers a PDF of the invoice with an embedded checkout link.

Dashboard: Open the invoice → Send

curl -X POST "https://api.live.paisr.tech/v2/invoices/{invoice_id}/send" \
  -H "Authorization: Bearer <token>" \
  -H "User-Agent: MyApp/1.0"

Hosted Checkout

Each invoice comes with a unique, time-limited checkout session:

https://invoice.paisr.tech/<session_token>

Sessions expire 30 minutes after generation. Once the customer completes payment, the invoice is automatically marked as paid and funds settle to your wallet balance. See the Payment Methods section for supported payment methods.

Managing Line Items

You can add, update, or remove line items on any invoice that is in draft or unpaid status.

Add items

curl -X POST "https://api.live.paisr.tech/v2/invoices/{invoice_id}/items" \
  -H "Authorization: Bearer <token>" \
  -H "User-Agent: MyApp/1.0" \
  -H "Content-Type: application/json" \
  -d '{ "line_items": [{ "description": "Hosting", "unit_price": 25.00, "quantity": 12 }] }'

Update an item

curl -X PUT "https://api.live.paisr.tech/v2/invoices/{invoice_id}/items/{item_id}" \
  -H "Authorization: Bearer <token>" \
  -H "User-Agent: MyApp/1.0" \
  -H "Content-Type: application/json" \
  -d '{ "description": "Updated Hosting", "unit_price": 25.00, "quantity": 12 }'

Remove an item

curl -X DELETE "https://api.live.paisr.tech/v2/invoices/{invoice_id}/items/{item_id}" \
  -H "Authorization: Bearer <token>" \
  -H "User-Agent: MyApp/1.0"

Modifying Invoices

You can update the summary, currency, and due date of any draft or unpaid invoice. Once an invoice is paid or void it is locked permanently to preserve financial record integrity.

Subscription-linked invoices

Invoices generated automatically by a subscription cannot be modified or deleted directly. To remove them, delete the parent subscription and all associated invoices are removed automatically.

Applying Discounts

Vouchers can be applied to an unpaid invoice before or during checkout to reduce the amount due. See Discount Vouchers for details.