---
title: "PAN, GSTIN & Pin Code Validation"
description: "Instant algorithmic validation for Indian tax identifiers, business registration numbers, and phone formats."
order: 2
category: "Data Core"
updated: "2026-10-13"
---

# PAN, GSTIN & Pin Code Validation

Perform instant client-side and server-side algorithmic validation on key Indian business and identity identifiers without calling costly third-party APIs.

## Supported Formats

- **PAN (Permanent Account Number)**: Checks 10-character alphanumeric structure (e.g., `ABCDE1234F`), verifies 4th character entity type (`P` for individual, `C` for company).
- **GSTIN**: 15-character Goods and Services Tax Identification Number including state code check and checksum character verification.
- **PIN Code**: 6-digit postal code mapping to valid postal circles.
- **Indian Phone Numbers**: Validates 10-digit mobile series prefixed with `+91`.

## TypeScript Validation Example

```typescript
import { validatePAN, validateGSTIN } from '@authsetu/core';

const panResult = validatePAN('ABCDE1234F');
console.log(panResult.isValid, panResult.entityType); // true, "individual"

const gstResult = validateGSTIN('29ABCDE1234F1Z5');
console.log(gstResult.isValid, gstResult.state); // true, "Karnataka"
```