Definitely check the hose ends like Abe said. They can crack and get corroded and coolant can seep out. Had its happen a couple times myself.

Also sometimes when the water pump is going out it will leak from its "weep hole". While it's running get up under the front end and check the bottom of the water pump, being careful of moving parts of course.

And it's not probable since it's running fine but you can do a compression test to check for a head crack/leaking gasket. You can rent the tester from the usual auto parts stores and it's easy to check.

Sent via messenger pigeon. I talk, he types.