That moment you interview with the CEO and you are like, I really hope I get the job, since this is something really cool, you get all anxious because you passed the other interviews and you are at the last one. Then you get a call/message saying you have been accepted as a Frontend/Backend Engineer. This moment the first time around it feels Amazing so, you now got the job at a start-up everything is going according to the plan. Now let's get to real nitty gritty or what it really feels working in one. I will point the most important factors according to My experience.

Exciting - That excitement of your first day on the job is truly amazing, you get to meet your colleagues, you get a tour of the office, and of course you get to sit on one or in my case in 3 different meetings on the first day, but wait this is not the best part, the best part of every new job are the toys you receive, like a good start-up my toy was a Mac m1 , not a big deal. Of course this is only after you do all your legal work.

For most of my time, I really loved my job and it was great, beside exciting , it was fun, rewarding. Every new day brought a different challenge from getting that news that you will be the lead of the main product the company is putting out to production to completing that first project (MY BABY). A few of the challenges? well let's see from working with a developer that was not efficient and lacked the skills needed to be at a fast pace start up, this is a big NO NO, you really need to be able to work and more than that the biggest issue was the miscommunication, this is a key part of working in the tech industry. After almost 3 months of picking the slack of that coworker you realize he has to go, talk to your CTO and he not only agrees, but also asks you why you waited so long to speak up.

Other challenges, were depending on backend to finish so you can start hooking up the frontend, yes you can always mock the data and blah blah, but this was something that would take time and quite honestly I always felt like this would be the job of the backend. As well as designs not being completed and when they were completed already a version that you worked on was already outdated, because a new design was already implemented.

I will name the top 3 things that after working on start up I will never do again, One I will never again put my well-being behind me, during the my time in the company the first 6–7 months I would put the need of the company before me, I think this mainly had to do with the fact that when you start a new job, specially a Junior role with such a responsibility you simply don't want to fail and want everything to go as planned, but the hard truth it won't go as planned. Two, I will never work crazy hours, it does not matter the deadline, many companies specially startup will work under pressure and that is fine and all, but there needs to be a limit, I spent days working about 10–12 hours to meet deadline, and once when we were on tight deadline, I was asked if I could stay extra, after 12 hours of work, needless to say my brain was fried and couldn't write any decent code at all at that point, so I will never do this again, as well as working on the weekends, there were times I would work during the weekend and now after experiencing this, I have decided and put boundaries. My weekends are sacred. Lastly, I will never spend more than 2 hours on a problem without a break, this is a cliche that many of us face, there were countless of time where I would try to debug without any break, worst thing ever, really take an break and come back, you will find that when you see the issue with fresh eyes it will be easy to fix that pesky bug.

From this experience, I also gathered that unless a specific technology is required for you to learn it for your job, forget about it. You won't have time to learn a new, in my case I wanted to learn rust but if I really wanted to learn rust in free time, I would literally have no social life, not saying its impossible, just saying I rather have a social life.

Now, I have mainly talked about things that are bad, let's talk about the good things about working in a startup, by far and the most beneficial is the experience you will get, trust me when I say, your experience will go up so fast without you noticing, when you get put into a position of leading a project as a junior, although I had previous experience and didn't think myself of a junior just starting out, the experience you will gain from this is insane, from going from a Junior to a Senior in one year(all of this is relative to where you work and where you head next), if I were to work at a FAANG, I would probably be a Junior. 

Other good factors from working in a startup is that moment you see that first project get built and all the checks are green and it goes public, that feeling you get is really awesome, you see your work live being used by thousands of user the only word I can think is rewarding
Minor details that you might not think are important, but after working in a startup you will come to want. the whole work-life balance, like mentioned above there is none, and you will definitely will be asking for that the next time you interview for another company, the company culture is another thing you will be asking about for sure, you will notice that most start-up will say "yeah we pretty chill" FAKE!

At the end of the day though, you will be thankful to have worked in a start up for multiple reasons, from the exposure, experiences, recognition, responsibility, passion, that you get from the work that you have done.

Again all of this is my personal experience