Depends how low your costs are and long you can go without needing to make any money from it. If your expenses are manageable and profitability isn't an issue, it might make sense to improve your product (nicer UI, more features, etc) while growing your user base and getting more information about them (location, demographic, age, etc). This will improve your pitch to advertisers when decide to cash in by, perhaps, selling premium placement for ads by keyword (iOS, Python, Devops, etc).
One issue you might have is that your user's are "shortlived", I would imagine a typical user is going to use it for a couple of months every 2-3 years, hence why I'm stressing quick growth.
That makes a lot of sense. My costs are essentially $0. My time is the largest factor. Agreed the user's are most likely "shortlived", but I collect emails which could be nice for something like a newsletter.
Yeah, newsletters seem big these days so that could work.
Alternatively you could let users make profiles with their preferences for their ideal job (remote only, MEAN stack, >£80k, etc) and notify them when a matching ad appears, you could even charge for this. This strategy allows you to also charge employers to contact/see your users, I think Dribbble does this, so it might be worth taking a look there.
Good luck and let us know how it works out, I love hearing about stuff like that.
One issue you might have is that your user's are "shortlived", I would imagine a typical user is going to use it for a couple of months every 2-3 years, hence why I'm stressing quick growth.