What is a tax API?
A tax API is an interface that lets your software submit a sales invoice electronically to a tax authority and receive back a verifiable fiscal invoice number and QR value. Instead of manual filing, your POS or ERP makes one HTTP call per sale. In Pakistan the authorities are FBR (goods, federal) and PRA, SRB and KPRA (services, provincial).
Why tax APIs exist
Tax authorities want every taxable sale reported at the moment it happens, with a QR the buyer can verify. Doing that by hand does not scale. A tax API automates it: your software sends the invoice, the authority records it and returns proof to print on the receipt.
What a tax API call looks like
With TaxBridge it is one request and one response, whatever the authority:
{
"success": true,
"data": {
"invoiceId": "INV-10001",
"submissionId": "sub_01J8ZK7M4QW3RTYV6XB2N9C5PD",
"authority": "PRA",
"environment": "sandbox",
"status": "APPROVED",
"authorityInvoiceNumber": "PRA-123456",
"qrCode": "PRA-123456",
"quota": { "limit": 10000, "used": 6501, "remaining": 3499 }
},
"requestId": "REQ-20260810-A1B2C3D4"
}The four Pakistan tax authorities
| Authority | Covers | Where |
|---|---|---|
| FBR | Sales tax on goods | All Pakistan (federal) |
| PRA | Sales tax on services | Punjab |
| SRB | Sales tax on services | Sindh |
| KPRA | Sales tax on services | Khyber Pakhtunkhwa |
A tax API gateway like TaxBridge lets you integrate all four through one API.