---
title: "Invoice Processing"
space: "Digital Invoicing"
url: "https://docs.kodlyft.com/digital-invoicing/invoice-processing"
updated: "2026-05-16"
---

This document explains the runtime document flow for sales invoices, purchase  
invoices, and POS fiscal flows.  
  
## Document Events  
  
The app hooks into:  
  
- `Sales Invoice.before_submit`  
- `Purchase Invoice.before_submit`  
- `Item.before_save`  
- `Company.before_save`  
  
## Company Before Save  
  
The app prevents duplicate sale types in the company configuration.  
  
## Item Before Save  
  
If an item has an HS Code but no HS UOM, the app auto-fetches the linked UOM.  
  
## Sales Invoice Flow  
  
The sales invoice flow has two branches.  
  
### Standard DI Sales Invoice  
  
This path is used when the invoice is not POS.  
  
1. Check whether DI is enabled for the company  
2. Check whether the customer has digital invoicing enabled  
3. Validate per-item DI fields  
4. Validate SRO requirements for sale types that need them  
5. Build the FBR DI payload  
6. Post automatically if `Auto Post on Submit` is enabled  
7. Save the FBR invoice number, posting time, QR code, and DI log  
  
If the DI API rejects the invoice, the app raises a validation error and stores  
the failure details in `DI Log`.  
  
### POS Fiscal Sales Invoice  
  
This path is used when the invoice is POS and the POS Profile has FBR  
integration enabled.  
  
1. Validate that each item has a customs tariff number  
2. Load POS Profile FBR credentials and endpoint settings  
3. Resolve payment mode into the FBR payment mode code  
4. Build the POS fiscal payload  
5. Submit the payload to the FBR POS endpoint  
6. Save the fiscal invoice number and posting timestamp  
7. Generate a QR code  
  
## Purchase Invoice Flow  
  
For purchase invoices:  
  
1. Check whether DI is enabled for the company  
2. Validate item-level HS code presence  
3. Build the DI payload  
4. Post automatically if `Auto Post on Submit` is enabled  
5. Save the response details in `DI Log`  
  
## Manual Actions Available in the UI  
  
On submitted sales invoices, the app can expose:  
  
- `DI Preview`  
- `Post to FBR`  
- `Validate with FBR`  
- `Verify Buyer`  
  
On submitted purchase invoices, the app can expose:  
  
- `DI Preview`  
- `Post to FBR`  
  
## QR Code Flow  
  
When an invoice is posted successfully and an FBR invoice number is available,  
the app generates a QR code and stores it as a base64 PNG data URI for UI and  
print use.  
  
## Print Output  
  
The app ships a `Sales Tax Invoice` print format that can render FBR-specific  
invoice data and the generated QR code.