[echelon]

This is absolutely not true.

I would expect a senior engineer to come into a new job and be able to propose the design a new service very quickly - its API, architecture, datastores (including sharding, replication, active-active multi-master designs, ...), DR strategy, how it fits into the ecosystem, how to scale it to thousands of QPS, etc.

[quantumhobbit]

I would too, but I have worked with plenty of people with the word senior in their title who wouldn't be able to do a any of that. I've also met "juniors" who do carry the world and build great systems.

The problem is that titles get inflated and can't be relied on as much as we would hope.

[gaius]

You might expect it, but I've encountered plenty of 23-year-old Senior Network/Software/whatever Engineers with just 1 year of experience. Basically as soon as they'd implemented a single feature, they would consider themselves senior.

Personally I say a senior engineer is one who solves problems by the most appropriate means. Maybe he fixes a "bug", maybe he/she knows enough about the problem domain, the use cases, the dependencies, the history and changes the documentation instead. Maybe he/she tells a junior engineer "figure out how to scale that" and uses experience to know what part of the system really needs to scale. And so on and so on. A senior engineer spends little time coding and lots of time mentoring.