What counts as specialization

Yes: you can specialize in domains specific to your company (knowing how x product works for your company). As an early career engineer, I'd just focus on finding something you're comfortably able to do good work in first. You'll have a feel for depth and your interests once you've hit a good comfort level. Then you can start thinking about how you want to specialize, using that understanding of yourself and your skills as a guide.

Does this apply to areas beyond languages and frameworks?

Yes! Some example areas of specialization can be Data Engineering, Machine Learning, Data Analytics, Frontend, Infrastructure, DevOps, Security, Mobile development, etc.

Other types specialization can be in deep tech like storage technologies, networking, GPU optimization, etc. These are less common and typically happen at companies developing the next generation of databases, data warehouses, etc. Think Snowflake, Databricks, or even specialized divisions at companies like Meta, Google, Nvidia, et al.

These specializations also have varying degrees of coding skills required (something to consider based on your interest and intuitiveness).

Yet others are language and framework specific, like you mentioned.

There are primarily two ways in which engineers come to specialize:

1. Their first/second job is in one of these fields.
2. They choose to transition to one of these fields intentionally after being a backend engineer (most typically, although they can transition from Frontend or Fullstack as well).

When engineers start out in their careers, they typically begin in backend, frontend, fullstack (or increasingly mobile too) because these areas have the most demand, but they are also vast, and nearly impossible to build mastery in. I say this from experience, having been a backend engineer for 16+ years! :)

This brings us to the pros of specializing: your chances of mastering one area are much higher than being a competent Jack of All Trades (backend engineers are also called "generalists"). Specialization focuses your efforts, builds up your expertise over time, and positions you well to excel at your job. Expertise keeps imposter syndrome away, and often earns you respect at the workplace because you become a unique value-add compared to a generalist that can be replaced more easily.

The cons of specializing are that it restricts your surface area—you'll be able to apply for specific jobs only and work in teams that need fewer people. For example, a Security team is usually much smaller than the number of backend engineers a company hires. But I don't see this as a major problem because these specialized roles will be increasingly in demand (even though their nature will change with the advent of AI, for example).

It's usually a good idea to begin with a generalist role and learn the ropes of software development in general before going into a specialized role. So you are doing it right in your current role by "focusing on deepening my expertise in API integrations and developing end-to-end developer tools"! :)

Feel free to ask follow up questions.