20-30 people (was there a few years with ebbs and flows). We had long hours and the first few years it was exciting. We built a lot of stuff and didn't know about certain practices - especially DevOps, so when we got one, there was a lot of work to do.
For me, it taught me autonomy. You had to learn to own something and be able to educate others on how it worked to raise the bus factor above 1, optimally above 3 (it's a start up after all).
Startups are often founded with the goal of being bought. Depending on where you work, they might care about code quality, testing, design, and all those nice things, but being first to market is probably the biggest concern. We had to strike a balance between being very agile and being able to deliver quality, maintainable features. Code was a vessel, an enabler, a necessity.
You had to hit the ground running when you arrived and be ready to learn a lot on the job. A prototype really meant something thrown together quickly that worked for a limited amount of usecases with fake data. Investors and customers had to be able to see the value first before wanting the real thing.
Ultimately, getting bought by a larger company made me leave. Things quickly changed from quirky, fun, stressful yet rewarding to procedure and corporate. Decisions weren't made by devs anymore but had to go through a horde of people. Teams were made around individual products instead of people being able to move freely between them to understand the vision of the company.
In retrospect, it was a nice stage in my life and I definitely learned a lot. If you haven't done it before, I'd recommend it if:
- you can deal with pressure
- like throwing stuff together or being on the other end of making a prototype viable
- want to start a business yourself someday (going through the phases of a startup teaches you about that)
- like being able to have a vision of the entire company (products, customers, fellow employees, ...)
- want to be at the forefront of something possibly new
Like any job, you can try it out for a few months and see whether you like it. If you don't do not force yourself to hang around. Your salary might not raise as fast regardless of how fast the startup is moving.
Good luck!
P.S This is but one experience from one country in Europe!