I agree with the subjectivity of the title “senior”. It applies to all professions really. Senior engineers are the same — only senior in a specific context (company, field, technology). However, I think we can all identify the junior; and that may be a more useful dichotomy for devs.

As an example, someone recently emailed me about an old tutorial of mine. He had only just started using Vue and so his Vue mistakes were “junior”; but he described his attempts at solving the problems himself in a way that was very logical. Unsurprisingly, he has 20 years of development experience in .Net, JAVA, etc and was trying out JS.

In my opinion, he is not a junior dev. Is he a senior? I don’t know. Don’t even care. All I know is he’s not a junior and so can take all I can give him. I don’t have to hold his hand through every step and step he doesn’t get, he can Google.