Should a developer know basic (or more) design? If so, why?

Of course cause it allows to get rid of possible misunderstandings during the process of working on a project

Short answer: Yes I think it is very beneficial for both sides. Developers need to have some knowledge about design principles and basic knowledge of design. In order to collaborate with designers and make design-related decisions, developers need to have knowledge about the terms, basic color, and typography knowledge at least.

Yes, it can be beneficial for a developer to have a basic understanding of design, if not more.Having a basic knowledge of design principles and concepts can help facilitate effective communication and collaboration between developers and designers.

Backend developer is not a must, skills in analytics in working with data will be more useful. For a frontend developer, design skills are a must.

As a designer, I can tell you that it makes a huge difference when working with an engineer that has a good product sense, especially in early stage companies. It's definitely not critical, and there are more important skills for the engineer, but it's a huge plus. Concretely it helps to: - Avoid spending a lot of time within the team to get aligned on the value of good design / product. - Make back and forth between design and engineering faster because everyone speaks the same language. - Prevent a lot of small quality issues (especially in terms of visual design) that are always deprioritised and rarely fixed otherwise. - Allow the engineer to make a bunch of design decisions on the fly which I think is gratifying both for the engineer and the designer. I'd say it's equally valuable for designers to get some knowledge of engineering for the same reasons.

Of course he shouldn't, unless his job requires it. But any additional skills are useful, develop the brain and may someday come in handy. Every experienced UI developer probably knows the basics of design and even more, since they work with it every day.

In general, yes, to understand the structure and workings of design. But I think it's not critical, because your job is to program, not to design. But like any skill it will only be useful.

I am actually a developer but 7 years ago I was only a graduated graphic designer. And honestly, it is a big plus value to know design. You can quickly switch from one tool to another and make a website a little bit pretty in no time.

i think you are only a real developer if you know how to design and know whats a good design, why else would you be a developer, design and layout is the start of every project (at least in frontend)

I think the best developers have conceptual knowledge of how a usable application should look like. They have an understanding of how a UI should look like to support usability and how it should operate. It's just a professional and personal experience to them. Mediocre and 9-to-5 engineers will need more guidance in these parts as they often don't have the experience or the will to understand concepts not tightly connected to their tasks.