GST & Tax

Access GST filing data directly from your invoice and purchase records. The GST API provides a review center for catching errors before filing, plus GSTR-1 and GSTR-3B data endpoints with JSON and Excel export support. Requires the GST module.

Endpoints

Review center

Returns a summary of potential issues in your GST data for a given return period — missing GSTINs, mismatched HSN codes, invoices without place of supply, and other common filing errors. Review and fix these before generating your returns.

Query parameters

curl "https://api.katixo.com/api/v1/gst/review-center?month=6&year=2026" \
  -H "Authorization: Bearer eyJhbGciOiJIUzI1NiIs..."

{
  "success": true,
  "message": "Review center data retrieved",
  "data": {
    "period": "June 2026",
    "totalInvoices": 142,
    "totalPurchaseBills": 38,
    "issues": [
      {
        "type": "MISSING_GSTIN",
        "severity": "WARNING",
        "count": 3,
        "message": "3 B2B invoices missing customer GSTIN"
      },
      {
        "type": "HSN_MISMATCH",
        "severity": "ERROR",
        "count": 1,
        "message": "1 invoice has invalid HSN code"
      }
    ],
    "readyToFile": false
  },
  "errors": null
}

GSTR-1 data

Returns all outward supply data for a given return period, structured into the sections required by the GSTR-1 form: B2B invoices, B2CS (B2C small), B2CL (B2C large), credit/debit notes, HSN summary, and document summary.

Query parameters

curl "https://api.katixo.com/api/v1/gst/gstr1?month=6&year=2026" \
  -H "Authorization: Bearer eyJhbGciOiJIUzI1NiIs..."

{
  "success": true,
  "message": "GSTR-1 data retrieved",
  "data": {
    "month": 6,
    "year": 2026,
    "gstin": "27AAECS1234F1Z5",
    "b2b": [
      {
        "customerGstin": "29BBBFM1234A1ZV",
        "customerName": "Kumar Distributors",
        "invoices": [
          {
            "invoiceNumber": "KTX/2026-27/0038",
            "invoiceDate": "2026-06-05",
            "totalAmount": 23600.00,
            "placeOfSupply": "29",
            "reverseCharge": false,
            "items": [
              {
                "hsnCode": "07139090",
                "taxableValue": 20000.00,
                "igst": 1000.00,
                "cgst": 0.00,
                "sgst": 0.00,
                "cess": 0.00
              }
            ]
          }
        ]
      }
    ],
    "b2cs": [],
    "creditNotes": [],
    "debitNotes": [],
    "hsnSummary": [],
    "documentSummary": {
      "invoicesIssued": 25,
      "invoicesCancelled": 1,
      "creditNotesIssued": 0,
      "debitNotesIssued": 0
    }
  },
  "errors": null
}

GSTR-3B data

Returns the summary tax liability data for GSTR-3B filing — output tax from sales, input tax credit from purchases, and net tax payable, broken down by CGST, SGST, IGST, and cess.

curl "https://api.katixo.com/api/v1/gst/gstr3b?month=6&year=2026" \
  -H "Authorization: Bearer eyJhbGciOiJIUzI1NiIs..."

{
  "success": true,
  "message": "GSTR-3B data retrieved",
  "data": {
    "month": 6,
    "year": 2026,
    "outputTax": {
      "cgst": 1121.25,
      "sgst": 1121.25,
      "igst": 1000.00,
      "cess": 0.00,
      "total": 3242.50
    },
    "inputTaxCredit": {
      "cgst": 850.00,
      "sgst": 850.00,
      "igst": 500.00,
      "cess": 0.00,
      "total": 2200.00
    },
    "netPayable": {
      "cgst": 271.25,
      "sgst": 271.25,
      "igst": 500.00,
      "cess": 0.00,
      "total": 1042.50
    }
  },
  "errors": null
}

Export endpoints

Download GSTR-1 and GSTR-3B data as Excel files ready for upload to the GST portal. Pass the same month and year query parameters. The response is an Excel file with Content-Type: application/vnd.openxmlformats-officedocument.spreadsheetml.sheet.

curl "https://api.katixo.com/api/v1/gst/gstr1/export?month=6&year=2026" \
  -H "Authorization: Bearer eyJhbGciOiJIUzI1NiIs..." \
  -o gstr1_june_2026.xlsx

Authorization

GST endpoints require OWNER, ADMIN, or ACCOUNTANT role. The GST module must be enabled for your organization. See Authentication for role details.