How long should a pet project take?

A first one: two to eight weeks at a couple of hours a day. If you're planning longer, you've almost certainly bitten off too much — halve the idea.

Should I publish the code if it's bad?

Yes. An employer looks at whether it's finished and readable, not at elegance. Beginners don't write perfect code, and nobody expects it from you.

Pet projects: what they are and why a beginner needs one

What it is

A pet project is something you build yourself, for yourself, with no client and no grade. The name comes from exactly that idea: something you look after because you want to.

It differs from coursework in one crucial way: nobody tells you what it should turn out to be. Every decision is yours, including the bad ones.

Why you need one

To show what you can do. CVs are read sceptically — anyone can write anything. A working link and open code are different: they can be checked.

To learn to assemble a whole. Courses hand out knowledge in pieces: functions here, a database there, an interface over there. Putting it together into something that works is rarely taught, and it's exactly what the job requires.

To have something to talk about. Interviews don't ask for definitions, they ask for stories: what you built, why that way, what went wrong. Without your own project there's nothing to answer with.

To find out whether you enjoy it at all. A useful side effect: a month of self-directed work makes it clear whether this is your line of work.

What counts

Almost anything, as long as it reaches "it works":

a tool you use yourself;
a bot that automates your own drudgery;
a site for friends or a small organisation;
a contribution to someone else's open project;
something built at a hackathon and finished properly afterwards.

What doesn't count: a pile of tutorials followed along to, and a folder holding the beginnings of five different ideas.

What it doesn't give you

Honestly: a pet project doesn't replace a job. It won't teach you to work with five-year-old code, negotiate with neighbouring teams, or meet someone else's deadlines.

Which is exactly why a project built with other people counts for more than a solo one. It brings the things solitude can't: divided tasks, discussion of each other's code, the need to negotiate.

The main trap

A pet project slides easily into an endless building site: today you rewrite it on a different library, tomorrow you add another section, a month later you're bored.

One thing cures it: agree with yourself at the start what "finished" means. A single sentence: "done when you can open the link and do this". Everything else comes later, if you still want it.

One finished small project weighs more than five started large ones. It shows in the change history, and in how a person talks about them.