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Validation applications čTečka and Tečka

Certificates of the basic vaccination schedule (1 dose of Janssen or 2 doses of other vaccines) will be valid in the Czech Republic from February 15th, 2022 for 9 months.This means that the certificates will expire after 9 months and will be displayed in red in the Tečka (Dot) application. It will continue to be possible to use a certificate of a booster (third) dose as proof of vaccination. 

(Pre) register for a booster dose
(Pre) registration for self-payers


From July 1st, the EU countries and Serbia will accept the Covid Pass (Digital Green Certificate, Digital COVID Certificate, or also the Certificate) as proof of completed vaccination against Covid-19. At the same time, the use of Covid Pass within the Czech Republic is also being prepared, eg for entering service establishments (this would prove compliance with the ONT rules).

Other countries are also being added, their list and information on the recognition of certificates from other countries can be found on the website of the Ministry of Health.

There are two applications - one containing a QR code (from the certificate) and the other that reads the code and shows whether the vaccination or Covid-19 test is performed at the required interval - either according to the rules of cross-border movement or within the entrance to stores, establishments, for cultural or sports events, etc.

čTečka (E-reader)

The application will read the QR code from a paper certificate, a downloaded certificate, for example from a mobile phone, or later from the Tečka application. The QR code is equipped with a digital signature that protects it against forgery. When checking the certificate, the QR code is scanned using the phone's camera, thus verifying the signature - the phone's display lights up green if the certificate is valid and red if it is invalid. The details of the certificate will show the person's name, date of birth, the validity of the certificate and the vaccine with which the vaccination was performed.

There is an application on Google Play and the App Store, before using you will see the conditions of use of the application.

Use for travel outside the Czech Republic: from July 1st.

Use for proving within the Czech Republic: the application is available from June 18th.

Possible reasons for certificate invalidity:

  • contains an incorrect data format and cannot be read, the data is not displayed
  • an electronic signature cannot be verified - specific reasons are coded in SIGxxx error codes
  • does not comply with the rules of validity (number of days after the first/second dose of vaccination, etc.)

Even for invalid certificates, if it is technically possible to obtain information from the certificate, the information from the certificate is listed on the Certificate detail page.

What are the SIGxxx error codes when the electronic signature cannot be verified:

  • SIG001 - Expiration missing in COSE
  • SIG002 - COSE is expired
  • SIG003 - COSE lacks KID (public key identifier)
  • SIG004 - Could not find active signing certificate for KID
  • SIG005 - Failed to extract the key from certificate data
  • SIG006 - Wrong signature data in COSE
  • SIG007 - Failed to verify the signature

čTečka (E-reader) – how to?

To check your customers’ certificates, you can use the validation app čTečka. You can download it for free to your mobile phone or iPad on Google Play and App Storeyou do not need any special device.

The first time you run the application, you must accept the terms of use of the application. After the confirmation, the home screen will appear. Click on the “SCAN QR CODE” button. The first time you run the application, it will request access to the camera – you need to allow the access to be able to scan QR codes. After that, a square will appear on your "camera" screen, point it to the QR code (it does not matter whether it is on paper, phone, watch, etc.). When the QR code is scanned, if the certificate is valid, a green screen will appear; if it is not valid, a red screen will appear.

You can find image instructions on how to use the Tečka and čTečka apps and the most common questions and answers on


The application in which the QR code is displayed. It is available on App Store and Google Play.

The application updates its parameters - validation rules and signature certificates of EU countries approx. every 24 hours.

Use for travel outside the Czech Republic: from July 1st.

Use for proving within the Czech Republic: the application is available from June 30th.

You can upload more certificates (eg family members) to Tečka by downloading the certificate to, or you can scan the QR code from the certificate you have already downloaded. The validity of the certificate downloaded in Tečka can be verified even without internet access.

You can find image instructions on how to use the Tečka and čTečka applications and the most frequently asked questions and answers at

Are you a service provider or organizer of mass events and you want to know how to best control the infectivity of visitors or customers? You can find help at

Frequent questions about this topic

Why is the original version of the vaccination certificate (issued before June 1st) always invalid?
Why don't I see a booster (or additional) dose certificate in Tečka?
What does Parameter Update mean?
Does the čTečka and Tečka application require Internet connection?
Does the čTečka application store information from certificates?
Why is the name listed twice in the certificate detail?
What will the app want access to on my phone?
Does it matter which vaccine we are vaccinated with?