What is the MRZ code and how can I use it for the automatic identity validation process?

The MRZ code or Machine-Readable-Zone is a set of alphanumeric strings that usually appear on the back of the identity document or passport .

It's a way of adding personal information in an alphanumeric code so that any machine or smartphone can read and convert this code into relevant information . Virtually all passports and identity documents are equipped with a MRZ (Multiple Marker Signature).
OCR -B) is used to read these alphanumeric character strings

In addition to the alphanumeric code, the MRZ uses a special font called OCR-B that facilitates automatic reading by cameras and scanners, even in tilted conditions or with poor image quality. This allows mobile devices and embedded systems to read and process the information quickly and accurately, facilitating the integration of automatic validation protocols in airports, access systems, or digital platforms.

Since October 2025, the European Union has implemented the Entry/Exit System (EES), which replaces the physical passport stamp with an electronic record of entries and exits. This system also includes the collection of biometric data (fingerprints and facial photographs) to enhance security and migration monitoring.

What data does the MRZ code contain?

The MRZ code, among the alphanumeric character strings, contains the following data :

• Line 1:
  • Document type (P for passport).
  • Issuing country (three-letter code).
  • Full name of the owner (in the format SURNAME <
• Line 2:
  • Document number (passport number).
  • Check digit of the document number.
  • Nationality code (three-letter code).
  • Date of birth (in YYMMDD format).
  • Verification digit of the date of birth.
  • Sex (M for male, F for female).
  • Document expiration date (in YYMMDD format).
  • DNI issuance date.
  • Expiration date check digit.
  • Personal identification number (optional).
  • Verification digit of the personal identification number.
  • Final check digit.
  • Each check digit is calculated using a specific algorithm based on the numeric and alphabetic characters in the corresponding field.

Each MRZ element is accompanied by a check digit calculated using standard algorithms to detect reading errors and prevent fraud. In addition, validation systems compare this data with official databases and international templates to ensure the document's authenticity and internal consistency, which is essential to prevent forgery or alteration.

The body that regulates the information contained in the MRZ code is the International Civil Aviation Organization (ICAO), known in English as the International Civil Aviation Organization (ICAO) .

ICAO establishes the rules and recommendations for the issuance of travel documents, including passports and visas. These standards are collected in document 9303 entitled "Mechanical Reading Travel Documents" , which details the technical specifications for mechanical reading documents and establishes the technical specifications and standards for travel documents, including passports and visas.
Document 9303 covers various aspects, such as:

• Document layout
• Data format
• Verification procedures
• Security requirements

This standard is adopted internationally to guarantee the interoperability and security of travel documents.

When is the MRZ code used?

The MRZ code has several types of use, mainly in the field of security and border management . Here are some of the most common:

Passport control at airports

Passport control machines at airports scan the MRZ to verify the authenticity of the passport and the traveler's identity quickly and accurately.

Visa processing

Visas also contain an MRZ that facilitates verification and authentication at a country's entry points.

border control

In eGates or electronic gate systems, the MRZ is used to allow automated entry of passengers, reducing waiting time and increasing the efficiency of border control.

Hotel Registration

Online Check-in : Thanks to the Check-in Scan , hotels can quickly record guests' passport or ID details, streamlining the check-in process.
Currently, many hotels , airports , and organizations use automated systems that scan the MRZ (Regular Identification Number) to perform check-in, guest registration, and access control, streamlining the process and reducing human error. These technologies integrate with official databases and biometric systems to efficiently and securely verify user identity.

Access control in high security facilities

In facilities such as nuclear plants or government buildings, the MRZ can be used as part of the access control system to ensure that only authorized persons can enter.

Fraud Prevention

By providing a standard and secure way to encrypt personal information, the MRZ helps prevent the fraudulent use of counterfeit travel documents.