I have been using JWT[1] since it's initial push as a mainstream authentication method. There's plenty of libraries that support it and make it easier to use[2]. There's even 0Auth[3] that is a company based around offering authentication services. Simply check for a valid token in the Authorization header, check out the introduction [4].

The library I've linked brings up a good point to make sure that you know the difference between decoding and verifying the token, but after that it's fairly plain sailing.

[1]: https://jwt.io [2]: https://github.com/auth0/node-jsonwebtoken [3]: https://auth0.com [4]: https://jwt.io/introduction/