LeetCode Timer by Brian Ko

LeetCode Timer
LeetCode Timer is a Firefox extension for timing LeetCode problems. Whether you're practicing time management while solving problems or you simply want to understand how long you're taking, LeetCode Timer provides an easy way to time yourself - no more going back and forth between your phone's timer and your problem!

Features
The extension will embed a stopwatch, right next to the Run Code and Submit buttons, into any LeetCode problem you're solving.

The following are some of the features that will be added soon™:
• ⏱ Switch between timer mode (count down) and stopwatch mode (count up)
• ⏳ Set time limits - customizable based on problem difficulty - for timer mode
• 💾 Save time spent when submission is accepted

and more!

If there are other features you'd like to see, please create an issue