Starting out
When you're starting out your career as a software developer, you'll typically get a first role as either a backend or frontend dev, and after a couple of years, gain some experience on the other side to become a full stack developer.
Company specific lock in
Since every organisation has its own tech stack, a full stack developer in Company A will have a different set of skills than one in Company B. Those additional skills you learn are still useful to boost your knowledge - it can include: specific cloud services, CI/CD, containerization, DevOps processes, a domain specific library or framework, and the company's SDLC process.
At this point many developers stay committed to their company's tech stack and remain working as a full stack developer for several more years. My advice - don't just coast as a full stack developer, branch out!
Branching out
Don't limit yourself to web apps.. branch out as soon as you get the chance, by getting some experience with any of these (if possible as part of your day job)...
- Native mobile app development (Swift or Kotlin)
- Cross platform mobile app development (Flutter or React Native)
- Desktop app development
- A newer backend programming language (Golang, Rust or Elixir)
- AI & ML
- UI/UX design using a tool like Figma
Some other ideas (which might need to be in your own time)...
- IoT (Arduino or Raspberry Pi)
- Game development (Unity or Unreal)
- Blockchain development
Become a generalist
Your aim is to become a generalist - someone who has deep knowledge in two or more areas and maintains a broad knowledge across many platforms, languages and frameworks.
After becoming a generalist, you'll be able to switch up your job roles, stretching your capabilities a bit each time you move. You'll find that you can apply for a larger variety of roles, increasing the possibility to land your dream job.
Adapt to new roles
Your varied knowledge will make it easier to apply your skills in new and unfamiliar areas, building up after some years to become a senior developer. Once there, its possible to remain at the senior level for an extended period - as long as you still enjoy it and are still learning, why not.
Thanks to reddit user -NewYork- for this meme