A growing number of US states are letting residents prove their identity digitally, offering a more modern method than physical credentials for purchasing age-restricted products, seeking government benefits, or even checking in at the polls.

The technology’s continued rollout is poised to test business’ enthusiasm and the public’s willingness to embrace digital verification in a wider range of interactions. Many states are allowing the use of mobile driver’s licenses and identification cards as an alternative to their traditional counterparts, though ID holders are still told to carry their physical credentials.

One of the most widely accepted current uses is at …