What’s the difference between a coder, programmer, developer and a software engineer? I see many people who attend a 2 month coding bootcamp where they learn html, css, javascript and put software engineer in their title

In the same line of thought I can attend house of cards lessons and call myself construction engineer. People can call themselves whatever they want and it's pointless to fight that; however, people like the ones in your example most probably won't even get called for an interview.

Programmer can code.
Developer can plan what to code.
Software engineer can plan why to code what, as well as know which tools might be the best tools for the job.

Every organisation uses the titles differently. I wouldn't overthink it too much.

The best kinds of job descriptions are those where you have a title not matching the description neither the tech stack nor the payment.

Like
...

Looking for a senior consultant doing big data in PHP using javascript for 32K Euro per year.

And some of the shit I read hurt my brain even more than that last sentence...

Technically, nothing. The IT industry likes to cheapen the word 'Engineer' by allowing people who have never studied Engineering (which is an actual discipline - like Law) to call themselves Engineers.

Any idiot can write some crappy code and call themselves a coder/programmer/developer/engineer/rock star, thats why in a job interview you get quizzed on what you *should* know as well as being asked to provide examples of work you have done.

Engineer is a title that comes with a degree that you can earn by study. At least here in NL you may officially call yourself an engineer if you have earned that title that comes with a degree. Programming or coding is a different ball game than engineering. Any person who can program can be considered to be a programmer or coder, that includes the sales manager programming Excel, the hobbyist just programming for fun but also the person writing these new stored procedures.

A developer is someone who is able to do more than just program: can fully develop a front end component, a back end service, a new db schema including all that's needed etc.; proficient in at least one layer of the (full) stack.

An engineer however must be able to do the whole full stack: from requirements analysis, to functional and technical design, db schema design, architecture, front end, back end... just everything that you need to professionally and methodically develop software from scratch.

@CodeMasterAlex that, and also : engineers have a broader cursus : physics, mechanics, chemistry...
Developer cursus is more focused on code, if not exclusively dedicated to it.

@react-guy absolutely! And that's also what's missing in many sofware development or programming courses. I mean almost any one can learn to program but crafting software of good quality requires a lot of knowledge, not only about programming and languages, also architecture, principles (solid etc.), quality and much more. Stuff you don't get taught in programming courses.

The difference I experienced is that you can give an engineer a problem and they will come up with a solution and most probably an implementation of that solution. A developer/programmer on the other hand is mostly presented a solution and is able to implement it. That doesn't mean they can't solve problems, they can but not to the same extend as an engineer. Also that isn't a hard line, there are people who are more or less skilled in solving problems ofc, but usually you can filter out the engineers by giving them ever harder problems to solve.
Another point is the approach to problems. An both will try to find a solution but an engineer will do a thorough analysis on the problem and even if a solution can't be found you will get an analysis about why.

That being said being an engineer in Germany requires a degree. Although engineers a described above and engineers with a degree are not necessarily the same group.