indycheck — Offline Indian ID validator

Validate PAN, Aadhaar, GSTIN, IFSC, UPI IDs, mobile numbers, PIN codes, TAN, CIN, LLPIN, Voter IDs and vehicle numbers — instantly, on-device, with no network call and no data leaving your server. One Rust core, bindings for JavaScript, TypeScript, Python and Rust.

Get started →Try the playground

New in v0.2.0: Bharat (BH) series vehicle numbers — 22BH1234AA now validates. Read the Vehicle docs →· Full changelog →

Install

npm install indycheck

import { validatePan } from 'indycheck';

const r = validatePan('AAAPL1234C');
console.log(r.ok);        // true
console.log(r.parsed);    // { entity: 'Individual', entity_code: 'P' }
console.log(r.reason_hi); // 'मान्य प्रारूप।'

Try it — right here, offline

Try: · · · · · ·

This demo runs 100% in your browser — the value you type is never sent anywhere.Open the full playground →

Why indycheck

🪪 12 validators

PAN, Aadhaar, GSTIN, IFSC, UPI, mobile, PIN, TAN, CIN, LLPIN, Voter ID (EPIC) and vehicle numbers.

🔌 Fully offline

No API keys, no network calls, no per-check fees. Works in a Lambda, a CLI, or a browser with no internet.

📦 Zero dependencies

One small Rust core compiled to native, Node and Python. Nothing to audit, nothing to break on install.

🇮🇳 Hindi + English reasons

Every failure comes with reason_en and reason_hi, so your form errors make sense to every user in India.

🎛️ Strict / lenient options

Control spaces, hyphens, +91 normalisation and uppercasing per call — strict for APIs, lenient for messy user input.

🎭 Masking & formatting

mask('aadhaar', …) → XXXX XXXX 0124, format('mobile', …) → +91 98765 43210. Display-safe by default.

🦀 Rust core

One implementation, one test suite — the same rules in JavaScript, Python and Rust. No drift between ports.

⚡ Batch-friendly

Validate thousands of rows in milliseconds. Built for CSV imports, signup forms and KYC pre-checks.

🎲 Test-data generators

generate('pan') gives you a valid-looking value for tests and seed data — clearly labelled TEST DATA ONLY, never a real ID.

🔍 Structured output

Every result returns a stable error code, a parsed breakdown (state, holder type, bank code…) and the normalised value.

🧩 Framework integrations

Ready-made Zod schemas, React Hook Form / Yup resolvers and Pydantic types — drop indycheck into the form library you already use.

⌨️ CLI

indycheck validate, detect and generate — check a single value or a whole CSV from your terminal.

Supported IDs

ID	Format	Checksum	Example
PAN	5 letters + 4 digits + 1 letter	Format only — entity reported, not enforced	`AAAPL1234C`
Aadhaar	12 digits, first digit 2–9	Verhoeff	`234567890124`
GSTIN	15 chars: state + PAN + entity + Z + check	Mod-36 Luhn	`27AAAPL1234C1ZE`
IFSC	4-letter bank code + 0 + 6 chars	Format only — no public checksum	`SBIN0001234`
UPI ID	`handle@bank`	Format only — no public checksum	`9876543210@paytm`
Mobile	10 digits starting 6–9 (+91 ok)	Format only — no public checksum	`9876543210`
PIN code	6 digits, first digit 1–9	Format only — no public checksum	`781001`
TAN	4 letters + 5 digits + 1 letter	Format only — no public checksum	`MUMB12345C`
CIN	21 chars: L/U + industry + state + year + type + no.	Format only — no public checksum	`U12345DL2025PTC123456`
LLPIN	3 letters + 4 digits (`AAA-1234`)	Format only — no public checksum	`AAA-1234`
Voter ID (EPIC)	3 letters + 7 digits	Format only — no public checksum	`ABC1234567`
Vehicle	State format (8–10 chars) or Bharat (BH) series `YYBH####XX`	Format only — no public checksum	`DL01AB1234` · `22BH1234AA`

Error codes — machine-readable, stable across releases

Code	Means	Example
`VALID`	Fully valid	`AAAPL1234C`
`INVALID_FORMAT`	Characters or pattern don't match	`ABCDE1234` as PAN
`INVALID_LENGTH`	Wrong length	`AAAPL123C` as PAN
`INVALID_CHECKSUM`	Verhoeff / Mod-36 Luhn check failed	`234567890123` as Aadhaar
`INVALID_FIRST_DIGIT`	First digit not allowed	`5123456789` as mobile
`INVALID_STATE_CODE`	Unknown state code	`99AAAPL1234C1ZE` as GSTIN
`INVALID_HANDLE`	UPI handle missing or unknown	`rahul@`
`UNKNOWN_TYPE`	No known ID format fits (`detect` only)	`hello world`

Branch on code, never on the reason text. Every failure also carries a Hindi reason (reason_hi). Full error-code table →

⚠️ Honest limits — read this first

indycheck validates format and checksum only. It does not — and cannot — tell you whether an ID is real, active, or belongs to the person who typed it.

No UIDAI, NSDL, GSTN, MCA, ECI or bank lookup. A "valid" Aadhaar may still be fake; a "valid" PAN may not exist.
It does not verify ownership, KYC status, or whether a bank account / UPI handle is live.
Aadhaar numbers are sensitive personal data — never log them, never store them in plain text, and prefer masked values (XXXX XXXX 0124).
Use indycheck as a first-pass form check before a real verification provider, not as a replacement for one.