I had a strategy for this that I frequently recommend to people. Back when I was "in the game" and living in NYC, I used to take 1-2 interviews per month despite being happy in my then current role. I was up front with current and prospective employers about this.
This strategy served me well on many fronts: confidence in my skills and my options, familiarity with evolving interview trends, and networking opportunities with team leaders in a tight knit industry. It also allowed me to chase roles/positions which I wasn't immediately qualified for without feeling stress and anxiety, and was immensely helpful later on as an engineer turned startup CEO to know what product/project management interviews should feel like.
YMMV, software engineers can usually get away with murder.
It really all depends on how you frame it. I probably used terminology like “taking meetings with” instead of “interviewing at”. Just make sure it’s not with competitive companies and maybe more importantly not with sister companies under shared VC funds.
Honesty goes a long way, and if your employer is going to fire you because you are keeping tabs on your market value then you need a new employer anyway.
I did the same thing for a couple of years here in Boston. (I stopped when I found a job I really liked and developed deeper extracurricular hobbies.) Interviewing can be fun if you have the right kind of mindset for it and you meet all sorts of people. Multiple people I interviewed with, I've run into down the road.
This strategy served me well on many fronts: confidence in my skills and my options, familiarity with evolving interview trends, and networking opportunities with team leaders in a tight knit industry. It also allowed me to chase roles/positions which I wasn't immediately qualified for without feeling stress and anxiety, and was immensely helpful later on as an engineer turned startup CEO to know what product/project management interviews should feel like.