# How to use the Authentication REST API (video)
VP of Technology Rune Synnevåg takes you through Signicat Express' Authentication API, when you should use REST vs OIDC, which parameters to use, and how it actually works. You can try it out on your own if you create a free user on our test environment:
For written instructions, refer to our Quick start guide.
Questions, comments, or suggestions? Check out our community (opens new window).