How do I decline an offer from a job I'm not longer sure about?

I'm currently job hunting. A few weeks ago I got a call from one of the jobs I applied to inviting me to an interview. The job was at a startup (I couldn't find very much information about them, the website isn't great), and I was alright with that because the position seemed interesting.

After I showed up, I realized the company was much smaller than I anticipated (just the original2 founders), but they are in the process of hiring a few people.

I went through two rounds of interviews with them, and they are in the process of drafting an offer for me. However, I am not so sure I want this job anymore, just based on the following:

• I see a major flaw in their testing protocols that I think will cause problems with the product that they're currently advertising. I already have experience in this technology and that is the reason for why I think they will run into huge problems when they move to non-ideal environments.
• It being a startup, I anticipate the typical work days will not just be8 hours and I want to have time for hobbies and life in general.
• Lack of certain job stability as one might have with a larger corporation, I don't even know if I will have vacation days
• They want me to start part-time before my anticipated starting date. I said I could, but honestly it would be so much easier if I didn't :)

Hi... Do you mean you applied for a job and you were successful but you no longer need the job!?

If so, and depends on the communication method, you should professionally reply that due to certain circumstances (you got a different job, you have family responsibilities...etc) you cannot take the offer.

Tanking and Apologizing !

Thanks for the invite,

I regret to say the question is not clear for me, and I can not provide an answer as long as I do not understand the question.

Totally agree with above answers