CIN

Validates a Corporate Identification Number (CIN): the 21-character code the Registrar of Companies (MCA) allots to every company at incorporation. Each segment carries meaning — listing status, industry, state, year, company type and registration number.

Structure

Positions	Meaning	Example
1	Listing status: `L` listed, `U` unlisted	`U`
2–6	Industry code (NIC)	`12345`
7–8	State code	`DL` = Delhi
9–12	Year of incorporation	`2025`
13–15	Company type (`PTC`, `PLC`, `OPC`, `NPL`…)	`PTC`
16–21	Registration number	`123456`

Rules

Rule	Detail
Format	`^[LU][0-9]{5}[A-Z]{2}[0-9]{4}[A-Z]{3}[0-9]{6}$`
Length	Exactly 21 characters
1st character	`L` or `U` only
Checksum	None — format only, no public checksum

Usage

import { validateCin } from 'indycheck';

validateCin('U12345DL2025PTC123456');
// { ok: true, code: 'VALID',
//   parsed: { cin: 'U12345DL2025PTC123456', listing: 'Unlisted',
//             industry_code: '12345', state_code: 'DL', year: '2025',
//             company_type: 'PTC',
//             registration_number: '123456' } }

from indycheck import validate_cin

r = validate_cin("U12345DL2025PTC123456")
print(r.parsed["company_type"])  # PTC

use indycheck::validate_cin;

let r = validate_cin("U12345DL2025PTC123456");
assert_eq!(r.parsed.unwrap()["state_code"], "DL");

Examples

Input	Result	Code
`U12345DL2025PTC123456`	✅ Valid, unlisted Pvt Ltd, Delhi, 2025	`VALID`
`L12345MH2020PLC123456`	✅ Valid, listed public company	`VALID`
`X12345DL2025PTC123456`	❌ Invalid — must start with L or U	`INVALID_FORMAT`
`U12345DL2025PTC12345`	❌ Invalid — 20 characters	`INVALID_LENGTH`
`U1234ADL2025PTC123456`	❌ Invalid — letter inside industry code	`INVALID_FORMAT`
(empty)	❌ Invalid	`EMPTY`

Error codes

Code	Means
`EMPTY`	Nothing was passed in
`INVALID_LENGTH`	Not exactly 21 characters
`INVALID_FORMAT`	Doesn’t match the CIN structure, or 1st character is not L/U

Parsed output

On success, parsed contains:

{
  "cin": "U12345DL2025PTC123456",
  "listing": "Unlisted",
  "industry_code": "12345",
  "state_code": "DL",
  "year": "2025",
  "company_type": "PTC",
  "registration_number": "123456"
}

Common company types: PTC private limited, PLC public limited, OPC One Person Company, NPL Section 8 not-for-profit, GPC government company, FTC foreign company.