The EU digital vaccine passport goes live today, allowing travelers from all 27 European Union countries to use their smartphone to prove that they have been vaccinated, have tested negative, or have recovered from COVID-19. It’s available for both iPhone and Android smartphones …

Officially known as the EU Digital COVID Certificate, it will allow airport scanners to read a unique QR code from your smartphone, verifying that you meet one or more of the requirements for travel.

BBC News reports that it is recognized by 31 countries in all.

The EU says that the certificate will allow easy entry into member countries.

It’s available in, and recognised by, all 27 EU member states – plus Switzerland, Iceland, Norway and Liechtenstein.

It’s free – and all EU citizens, as well as non-EU nationals legally staying or living in the member states (with the right to travel to other member states) can download it or obtain a paper copy.

Some countries have already been using the certificate on a voluntary basis – but it’s being officially introduced from 1 July with a six-week phase-in period.

Privacy was a key part of the specification for the certificate. Your code contains a unique identifier, together a link to the official body able to verify your status. This might be a database held by a health authority, hospital, or test center. The scanner verifies that your code is valid and allows you to pass the check, but does not retain any of the data.

The EU digital COVID certificate will have a speedy verification process and will help preventing the use of fake certificates across the EU […]

Holders of a valid EU digital COVID certificate should in principle not be subject to testing or quarantine when travelling within the EU.

England has its own digital certificate, available in the NHS App, which should be compatible.

Scotland and Wales don’t yet have their own digital certificates, only paper ones. The same will be true of Northern Ireland from the middle of this month. Paper certificates should, however, work in the same way.

Will the EU recognise the NHS Covid Pass? Not yet – but some individual countries, such as Greece and Spain, are already accepting it.

The EU says it’s working to ensure its digital certificate is compatible with similar products in non-EU countries. If it’s satisfied a non-EU certificate complies with EU “standards and systems”, it can decide to accept it across all 27 nations.

The IATA Travel Pass also works in the same way, and should similarly be compatible with scanners designed to read the EU digital vaccine passport.

Vaccinations are key to reopening countries for travel, as they dramatically reduce the risk of infection; reduce the severity of symptoms if someone is infected; and makes you far less likely to pass the infection to anyone else.