Last year, I have developed a JS library SM.js (https://github.com/slaypni/SM-15) which is based on the algorithm used in the latest SuperMemo.
I have also developed a web service (http://slaypni.github.io/flashward/) for memorizing Foreign words using the library. Through the experience of using it by myself, I felt that spaced repetition helped me to remember many words for learning English.
I am feeling that most (free) SRS are using relatively simple algorithms (for example, Anki is based on SM-2 which is developed in the late1980s). Although I am not sure SM-15 is better enough, there could be some room to improve it. It is nice if the library was helpful for some developers who create new SRS.
Newer isn't necessarily better with SuperMemo algorithms. They introduced tremendous complexity without strong evidence of increased effectiveness, last I looked into it - it seems to create more corner cases to manage, if anything.
I have also developed a web service (http://slaypni.github.io/flashward/) for memorizing Foreign words using the library. Through the experience of using it by myself, I felt that spaced repetition helped me to remember many words for learning English.
I am feeling that most (free) SRS are using relatively simple algorithms (for example, Anki is based on SM-2 which is developed in the late1980s). Although I am not sure SM-15 is better enough, there could be some room to improve it. It is nice if the library was helpful for some developers who create new SRS.