Official Journal of the European Union
Online verification of the certified electronic edition
  2. Portal of the Publications Office of the EU
  3. EUR-Lex
  4. CheckLex
  5. FAQ

What is CheckLex?

CheckLex is an application that enables you to verify the electronic signature and authentic character of an electronic edition of the Official Journal of the European Union (e-OJ). If verification succeeds, you are guaranteed that:

  • the electronic edition is authentic
  • it has not been changed since the date of its signature.

Verification can be done in any of the EU's 24 official languages. You can select a language via the drop down list in the top right hand corner of the homepage.

Why do I need CheckLex?

Effective 1 July 2013, the electronic edition of the Official Journal of the European Union (e-OJ) is authentic and produces legal effects, pursuant to Council Regulation (EU) No 216/2013.

The e-OJ bears an advanced electronic signature to ensure its authenticity, integrity and inalterability, in accordance with Directive 1999/93/EC.

Paper versions will no longer have any legal value, except for cases where – due to an unforeseen and exceptional disruption of the Publications Office's IT systems – the e-OJ cannot be published.

Official Journal – print editions with legal effect

What is an electronic signature?

An electronic signature has the same function as a written signature on a paper document. A document is signed electronically by attaching an electronic certificate to it.


  • Any change to the signed document is detectable, which means its integrity is guaranteed.
  • The document's publisher is identified with certainty, and the authenticity of the electronic signatory is assured.
  • It is impossible for the person or organisation that signed the document electronically to deny having done so.

What is an electronic certificate?

Like passports or identity cards, electronic certificates make it possible to verify that a person or organisation is who they claim to be. A certificate is an electronic file containing personal data on the certificate holder:

  • holder's identity
  • lifespan of the certificate
  • identity of the certification-issuing authority
  • signature of the issuing certification authority
  • holder's public key, used to verify signatures done by the holder.

What is electronic signature verification?

Electronic signature verification is a method for proving that there is a unique correspondence between a specific PDF edition of the OJ and its signature file.

Verification makes it possible to:

  • guarantee the integrity of the document.
  • authenticate the document signatory (only if the signatory is the sole holder of the private signature key).
  • verify the electronic signer's certificate.

In practice, CheckLex verifies that:

  • the "fingerprint" of the PDF is the same as the one indicated in the signature.
  • the signature has been issued by a trusted and authorized signatory.
  • the signature file has not been falsified.

If a signature is considered valid, CheckLex displays the date and time at which the signature file was created.

What are the technical requirements for using CheckLex?

You only need an Internet connection.

CheckLex is compatible with Internet Explorer 8, Mozilla Firefox 4 and with more recent versions of these browsers. Other recent browsers are likely work as well, but have not been specifically tested.