Ask HN: How to leave my current job

I work at a small (non-primarily-IT) start-up. My position is rather important since I am the only one who has the access to all the data, and the entire business is around that data. When they hired me they were looking for a person with strong integrity. Someone who would not sell their data to 3rd party. And that was me, I had bunch of offers from other firms to sell the data, and I never even thought about it.

But now the situation in company is quite bad. My pay is really low, paychecks are always late, the agreements about pay increase were never honored. But the thing that bothers me the most is the fact that they always keep quiet about that. For example I was supposed to receive a pay increase in September, I never got that, and they never said anything. I told them a few times that all I want is openness, and that never happened. But they are always full of promises that never happened. That is the worst part, because then I feel like a donkey that is being bribed by a carrot.

Now I want to change the job. When I tell them I'm obligated to stay here for 2 more weeks. That is really little time to find someone who will replace me. And even if I'm mad at them I'm still thinking about telling them that I'm looking for another job. But I'm not sure if I should do that.