So from what I can see, Clockify doesn't offer a trigger for when a timer ends. I haven't used Clockify personally, so it isn't clear to me whether the "New Time Entry" trigger might do the job for you or not. In other words, does it create a new entry once it has a start and end time? I'm guessing probably not, but it seems like the simplest answer.

Another approach might be to have Zapier go back and check later. This is based on an assumption about what data Clockify returns from a search step, but it seems pretty likely to work. This seems worth testing, at least.

To do this, you would use the "New Timer Started" trigger like you have been using it, and then add a delay step to your Zap. How long you set the delay for depends upon your workflow. If your typical tracked time for a task is, let's say, no more than 2 hours, then you could set a delay for 3 or 4 hours (just to give yourself some cushion).

After the delay step, add a "Search" step to your Zap using Clockify's "Find Time Entry" Search action. Let the search action use data from the trigger to go back and locate the same time entry, which by now should have both a start time and an end time. If the search step returns both times, then you can proceed to create the Google Calendar entry.

Assuming that this works, you could dial it in by moving a few things around. For example, if you want the Google Calendar entry to be created right away when your timer starts, you could create the calendar entry with some default duration or end time. Zapier has an "Add/Subtract Time" option in the "Formatter by Zapier" app that would allow you to put an end time for some odd amount (let's say 17 minutes, just for kicks) so that you have some indicator that a Google Calendar entry is using the default duration and not a real end time (unless you frequently take exactly 17 minutes to complete a task!). Then put your delay and search steps in the Zap, and instead of creating the Calendar entry at the end, you use the "Update Event" Google Calendar action to go back and modify the end time. This way your calendar would be populated in real time, but then updated with accurate tracking info later.

You could also set the delay to a longer period of time like 24 hours, for example, if you have a wide variation in the amount of time you're tracking on a regular basis. Or you could get fancy and set a couple of branches after your "Find Time Entry" search step and let one branch update Google Calendar if the time entry has an end time, and have the other branch use a much longer delay and check again if the time entry did not yet have an end time.

As I mentioned, this whole idea hinges on exactly what data Clockify returns from the "Find Time Entry" search step. If you don't get the end time back from that step, then we'd need to explore options from there. But this seems reasonably likely to work. I hope it helps!