kramank

Zero-dependency validators for Indian identifiers: GSTIN, PAN, IFSC, and pincode. Checksum-verified where a checksum exists (GSTIN), TypeScript-first, works in Node, browsers, and edge runtimes (no Node built-ins used).

Format validation only. These functions check that a string is a well-formed GSTIN/PAN/IFSC/pincode. They do not confirm the value is real, active, or currently registered with GSTN, the Income Tax Department, or a bank — that requires a live lookup against those systems, which this package does not do.

Install

npm install kramank

Usage

import { validateGstin, validatePan, validateIfsc, validatePincode } from 'kramank';

validateGstin('27AAPFU0939F1ZV');
// {
//   valid: true,
//   input: '27AAPFU0939F1ZV',
//   errors: [],
//   warnings: [],
//   stateCode: '27',
//   state: 'Maharashtra',
//   category: 'REGULAR',
//   pan: 'AAPFU0939F',
//   panEntityType: 'Firm',
//   note: 'Format check only — does not confirm this value is real, active, or currently registered.'
// }

validatePan('ABCPD1234E');
// { valid: true, entityType: 'Individual', ... }

validateIfsc('HDFC0001234');
// { valid: true, bankCode: 'HDFC', ... }

validatePincode('110001');
// { valid: true, zoneDigit: '1', zone: 'Northern Region — ...', ... }

Every validator returns the same shape — never a bare boolean:

interface ValidationResult {
  valid: boolean;
  input: string;              // trimmed, normalized
  errors: { code: string; message: string }[];
  warnings: { code: string; message: string }[];
  // ...plus decoded fields specific to each identifier
}

So a failed validation always tells you why (errors[0].code), not just that it failed.

What this package does not do

• No network calls, no live registry lookups, no "is this GSTIN actually registered" check.
• No maintained reference data for IFSC branches or pincode post offices — just the structural/zone rules encoded in the formats themselves.

The hosted Kramank API

Kramank (क्रमांक, "number") is a hosted API that builds on these same validators and adds what a pure format check can't give you:

• IFSC lookup — real bank, branch, and address data for a given IFSC code, kept up to date.
• Pincode lookup — real post office, district, and state data for a given pincode.
• The same GSTIN/PAN/IFSC/pincode format validation as this package, as a hosted endpoint — useful if you'd rather not vendor the logic at all.

See the API reference for endpoints and free-tier limits, or get a key directly on RapidAPI — BASIC (free, 500 requests/month) and PRO ($9/month, 50,000 requests/month) are both live.

License

MIT