I like runalyze very much as it fits my training planning and philosophy. While exploring its features as I am new to it I came up with one suggestion/feature that would be nice to have. Here it goes the case of application.
Training scenario: Interval Training (running) of 5x1000 m series with 3 min Easy pace between each 1000 m.
I usually run 1000 m at Interval pace, then take the lap (or split) with my watch and run at Easy pace for 3 minutes (about 600 m).
Then, as I want my watch to take the next 1000 m time, I stop the activity and start again from 0 (GPS measurement).
Note: if I don't stop the watch, I would run the 2nd 1000m from GPS measurement of 1600m to 2600m and so on.
Results: I have 5 workouts of 1600 m of which 1000 m is run at Interval pace and 600 m at Easy pace.
When I import the single workout into Runalyze I can only assign one activity type to the workout (which would be Interval), as you can see in the figure below.
However, this would bias the estimation of the VDOT value adn fitness, as the resulting average pace is slower than the IT pace and faster than the Easy pace.
Suggestion: add possibility to split the workout into customizable distances (e.g., 1st split: 1000 m, 2nd split: 600 m) and assign different activity type to each split.
I hope I explained myself clearly enough and not fell into any loop

Kind regards,
Antonio
PS: wonderful job!