I have been frequently frustrated when debugging issues as a backend engineer, by having to manually fiddle with timestamps - doing mental math to account for timezone differences, different timestamp formats between tools, calculating the difference between two timestamps, etc. I built a tool to do all these things in a single place.

Demo video: https://www.youtube.com/watch?v=pcBwIcqBLk8

I apologize for the potato video quality. I used free trial software and this was the first time for me to record or edit anything.

I also wanted to learn frontend development, and this felt like a good project for dipping my toes into it. I wrote a lot of code using AI, but quickly ran into trouble and had to take the reins. I still used AI to write tightly scoped functions and hooks, but kept most of the architecture in my head. I used AI to debug issues as well, and found it to be very useful at detecting issues that a new frontend engineer might make.

Everything runs on your browser (except for format inference for unrecognized timestamp formats using gemini-flash-lite). History and recently used timezones and formats are stored in IndexedDB in your browser.

Everything is hosted on free tier infrastructure - Cloudflare workers and the free tier of gemini-flash-lite. It felt incredible to be able to put something out there completely for free, without even having to enter my credit card anywhere.

If you find bugs, please report them here: https://github.com/viraniaman94/datetime-utils-issues/issues...

I didn't want to open-source it because I am not sure if this can take off in a significant way. If it does, I'd like to be able to make some money off of it if possible. If it doesn't, I'll open source it.

Happy to take questions and feedback!