Why does my government PDF show a yellow question mark?

Indian government PDFs are digitally signed using certificates from NIC, eMudhra, or other CCA India licensed authorities. Adobe Acrobat and most PDF viewers don't include India's Root Certifying Authority (RCAI) in their default trusted certificate store. So even though the signature is completely valid and legally recognised under the Information Technology Act 2000, your PDF viewer shows a yellow question mark because it cannot automatically verify the issuer. Kagazo checks your PDF against the actual CCA India trust hierarchy and gives you a copy with a permanent green tick visible on any device.

Is my document safe? Do you store my PDF?

Your PDF is processed entirely in memory during verification. We never write your file to disk, never store it on our servers, and never share it with any third party. The file is deleted from memory immediately after verification is complete. You can also verify this by checking our open source backend code.

Which documents does Kagazo support?

Kagazo supports any PDF digitally signed under India's CCA certificate hierarchy. This includes e-Aadhaar, PAN card, DigiLocker documents, ITR-V, Form 16, and all state government certificates from Tamil Nadu e-District, AP and Telangana MeeSeva, Karnataka Nadakacheri and eJanma, Kerala Sevana portal, and more.

My Aadhaar PDF is password protected. Will it work?

Yes. Enter your Aadhaar password (first four letters of your name in capital letters followed by your birth year, for example RAMA1995) in the password field that appears after you upload your e-Aadhaar PDF. We decrypt it in memory, verify the signature, and return a verified copy.

What is the difference between "Signature Valid" and "Signature Unknown"?

Signature Valid means the document is genuinely issued by the government authority and has not been modified. Signature Unknown means your PDF viewer cannot verify the certificate chain — this is a viewer configuration issue, not a problem with your document. Signature Invalid means the document may have been tampered with or re-saved after signing.

Does this work on mobile?

Yes. Kagazo is fully mobile responsive and works on any Android or iOS browser. No app installation required. Simply open kagazo.in on your phone browser, upload your PDF and verify instantly.

GST Council & GSTN ISO/IEC 7064 Standard

GST Number (GSTIN) Instant Verifier

Validate 15-digit Indian GST numbers, decode registered State and business PAN details, and mathematically verify the official MOD 36 error-detection checksum to prevent fake invoice fraud and protect your Input Tax Credit (ITC).

100% Client-Side Algorithm Privacy: All GSTIN checks run directly inside your browser. No searched vendor numbers or invoice data are logged on our servers.

GST Number (GSTIN) Instant Verifier

MOD 36 ALGORITHM

Verify 15-digit GST numbers, decode PAN and State, and export printable vendor due diligence slips.

Govt Portal

Enter 15-Digit Goods and Services Tax Identification Number (GSTIN)

Test Samples:

Segment Breakdown (15 Characters)

33State

AAACR5055KEmbedded 10-Digit PAN

1Entity

ZDefault 'Z'

RMOD 36

Invalid Checksum Detected (Potential Fake / Typo)

The format matches 15 characters, but the MOD 36 checksum character "R" does not match the computed algorithm value "E". Check for misread characters.

State JurisdictionTamil NaduState Code: 33

Embedded PAN CardAAACR5055K10-Digit Income Tax PAN

Taxpayer ConstitutionCompany / Private Limited / LimitedDerived from 4th PAN char

Entity Count / CheckReg #1Checksum: R (Mod 36)

Vendor & Invoice Details for Audit Slip (Optional)

Vendor / Business Name

Invoice / PO Reference

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Indian GST State Code Reference Table

State Prefix

33Tamil NaduSouth India

27MaharashtraWest India

29KarnatakaSouth India

07DelhiNorth India

24GujaratWest India

09Uttar PradeshNorth India

36TelanganaSouth India

37Andhra PradeshSouth India

32KeralaSouth India

19West BengalEast India

Frequently Asked Questions

Q:How do I know if a GST number on an invoice is genuine or fake?

A valid GSTIN must strictly follow the 15-character statutory format: 2 state digits + 10 PAN characters + 1 entity count + "Z" + 1 MOD 36 checksum character. Fake or forged GST numbers almost always fail the mathematical ISO/IEC 7064 MOD 36 algorithm. Kagazo computes this check instantly in your browser.

Q:What is the consequence of accepting a fake GST invoice?

If you pay GST to a vendor holding an invalid or cancelled GSTIN, the Goods and Services Tax Network (GSTN) will deny your Input Tax Credit (ITC) under Section 16(2) of the CGST Act. You may also face penalty interest up to 18% per annum.

Q:What information is embedded inside a 15-digit GSTIN?

The first 2 digits represent the State Code (e.g., 33 for Tamil Nadu). The next 10 characters (digits 3 to 12) represent the Permanent Account Number (PAN) of the taxpayer. The 13th character represents the number of business vertical registrations in that state. The 14th character is always "Z" by default, and the 15th is an error-detecting checksum.

Q:Is any searched GSTIN stored or tracked by Kagazo?

No. All validation algorithms, state mappings, and checksum calculations execute strictly in client-side JavaScript inside your browser. No taxpayer or vendor numbers are logged on our servers.

Input Tax Credit (ITC) Protection

Verify Before Invoice Payment

Never release payment on handwritten or unverified GST invoices without verifying the 15-digit GSTIN.

GSTR-2B Matching

Ensure vendor files GSTR-1 on time so the invoice reflects in your monthly GSTR-2B auto-drafted statement.

Related Verification Tools

Aadhaar + PAN Single PDF KYC Bilingual Affidavit Generator Official Masked Aadhaar Redactor

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