I implemented passkeys into our web app before most major websites had figured them out. While it wasn’t an important feature on the roadmap I worked on passkeys as a side project and was able to implement it was only 200 lines of code and no external libraries. I followed the specification
Our implementation ran from September 2023 till December 2023 and had no known vulnerabilities or issues. Our CEO remarked that it was one of his favorite features and was frequently surprised that other websites hadn’t implemented it yet.