I strongly recommend appmap.io The most useful feature I have found is the request recording which is pretty much instantaneous and outputs an array of beautiful diagrams of your application code: sequence diagrams, dependency maps, flame graphs, and very in-depth After reading most of the replies here I will say that while there are some great products made and in the making, appmap crosses off a lot of boxes when it comes to a developer driven tool. We plan to use this as the catalyst for onboarding developers into the complex world that is fintech, where encryption and abstraction drive product and productivity. having setup different models and pocs using this tool myself as well as platform and staff engineers have been impressed. It even logs the data so there’s something for the data scientists to gain from the work of this tool as well. Most importantly the dev team currently grinding the gears on this thing are very responsive and as an early user I’m impressed! I found an issue and in the slack community they monitor we’ve logged and found multiple ways to overcome obstacles. Definitely recommend it. Especially for devs who are onboarding and managers with new devs they’re onboarding.