What's the difference between a startup and a big company for your career?

The real difference is breadth versus depth, and speed versus scale. Startups make you broad quickly and teach you to operate with ambiguity; large companies make you deep, teach you rigour, and give you a credential. Both are legitimate, and the right one depends on what you currently lack. **Startup (30 people):** - You'll do many things — some outside your job title. Broad exposure fast. - Direct impact and visibility. Your work is used, and the founders know who did it. - Fast decisions, little process, and you can influence direction meaningfully. - Less mentorship, usually. Fewer senior people, less code review, less structured learning. This is the underappreciated cost and the main thing to interrogate. - Lower base salary, equity that is most likely worth nothing — the honest base rate for startup equity is zero, and you should treat it as a lottery ticket rather than compensation. - Higher risk: the company may not exist in two years. - Chaos, changing priorities, and sometimes poor boundaries around hours. **Large company:** - Narrower scope, deeper expertise. You'll know one area very well. - Structured learning: mentorship, code review, training, defined levels. - Better compensation and benefits, and real job security by comparison. - Brand on your resume, which opens doors afterwards — this effect is real and persists. - More process, slower decisions, more coordination, and a chance your work never ships for reasons unrelated to its quality. - Less visibility; your impact is a component of something large. **How to choose:** - **Early career with no strong mentorship yet**: the large company is often the better first move. Learning good practice from experienced people is hard to acquire later, and 'I was the most senior engineer at 23' can mean you learned bad habits with nobody to correct them. - **You already have solid fundamentals and want range and ownership**: the startup will accelerate you considerably. - **You need financial stability**: not a close call. - **You want to found a company eventually**: startup experience is directly relevant and hard to substitute. **The questions that actually decide it**, beyond the categories: who would you learn from, specifically? What's the runway and funding position? What did the last person in this role go on to do? Is the work itself interesting? And note that neither is permanent. Doing both across a career is common and makes you more versatile than either alone — the order matters more than the choice.