Professional Programming: The First 10 Years

Last month, April 2022, marked the 10 year anniversary of my start as a professional programmer.

I started programming earlier than that, but hadn’t been paid a salary. As a teenager I built websites and IRC bots and wrote tiny Python scripts. Then I stopped and played guitar for a few years. In my twenties, I rather coincidentally rediscovered how much I enjoy programming when I was asked to build another website and found out how much had changed about the web while I was away (it’s HTML5 now!).

That made me wonder whether programming wouldn’t be the better career choice than continuing to study philosophy at university. Robin answered that question for me by generously offering me a paid internship.

Now it’s been 10 years, which is, to be honest, neither a significant marker of my growth as a programmer nor my career, but realising that it’s been 10 years made me pause and reflect.

The following is a loose, unordered collection of thoughts that come up when I look back on the past 10 years. Things I’ve learned, things I’ve unlearned, things I’ve changed my opinion on, things I never thought I’d believe in and now do.

They’re very much products of the context in which I helped develop software: as an intern for Robin, then as a junior developer for Robin, as a software developer for a small German startup, as a senior software developer for a German startup inside a huge German corporation, and now as a staff engineer for a fully remote, asynchronous US startup. Take that as a disclaimer. I bet if I’d worked in a game studio, a hardware company, and a big tech corporation instead, this text would be very different.

Fearlessness is undervalued

Most of the programmers I look up to and learned from share one trait that is rarely talked about: fearlessness.

They dive into an unknown codebase without fear. They open up the code of a dependency that they suspect is misbehaving without fear. They start working on something without knowing how they’ll finish.

It’s inspiring seeing someone being fearless, but becoming fearless yourself is one of the best learning accelerators I’ve found.

You can’t predict the future; try and you might end up in trouble

We all know this. Of course, we can’t predict the future.

But it took me years to truly take it into account when programming.

In the first third of my career I’d think: we will need this, so let’s build it now.

In the second third: we might need this, so let’s prepare for it.

Now: we don’t know whether we’ll need this, it’s a possibility, sure, and it looks like we might need it, yes, but things change all the time, so let’s build what we know we need right now.

Of course I write code so it’s easy to test

I also write code so it’s easy to read and understand, or easy to delete, or easy to modify, or easy to review. I don’t write code only for the computer to execute.

Nothing really matters, except bringing value to the customer

Type safety, 100% test coverage, the ability to fluently express business logic in code, perfect development tooling, an efficient system that wastes no resources, using the best programming language for the job, an elegant API design, a fast feedback loop, writing great code – these are not the goal.

Here’s the goal: providing value to your customers, by shipping software that solves their problem, repeatedly.

The things above help you do that – faster, cheaper, more efficiently, safer, with greater joy – but they’re not the goal. The goal is to provide value to your customers.

The trap: it’s often easier to write software than to deliver it. But delivering is what it’s all about.

Perfection is unachievable

I’m not sure I ever thought it is, but now I’m certain it is not. Everything is the result of trade-offs.

You will never reach 100% on every axis that you care about. Something has to give. And when you think you did make it perfect, you’ll soon realise that you forgot something.

My aesthetics have changed too. Instead of looking for the beauty that lies in perfection I now think the program that succeeds despite its flaws is beautiful. Look at that little program go, holding the internet together, despite the 17 TODOs in it.

If you can’t connect it to the business, it doesn’t matter

You can refactor a codebase and clean it up significantly, making it easier to understand for everybody and easier to extend, but all of that won’t matter if that codebase gets deleted four months later because the project didn’t help the business.

You can spend weeks adding tracing and observability to all of the code you write, only to realise that nobody will ever look at it, because that code runs three times a day and never causes any problems.

You can tweak and optimize your code to run so efficiently that the company can halve the number of machines required to run it and then see that the costs you saved are nothing in comparison to the salary you were paid while optimizing.

You can spend your time doing fantastic technical work and still waste it.

Figure out what the rule is trying to prevent, then consider the rule optional

If you’d asked me 5 years ago whether TDD, Clean Code, Software Craftsmanship, and other schools of thought are dogmatic, I would’ve said “no! Can’t you see? Clean and good code is important!”

Now I look back at the time when I thought that a rule such as “a method should not be longer than 5 lines” was useful and shake my head.

It’s not about the rules! It’s about the problems these rules are trying to prevent. If you don’t have the problem they’re trying to prevent, or you can prevent it another way, you don’t need the rule.

Write tests that give you confidence that the system works as it should

Don’t worry too much about whether a test is an integration or an end-to-end test, a unit test or a functional test. Don’t fight with others about whether you should test private methods or not. Stop worrying about whether you should hit the database in tests or not.

Instead write tests that tell you the system is working the way it should. Ideally with 3 keystrokes and in less than 1 second.

This one took me a long time, a lot of ultimately useless discussions, and bugs in my code to learn.

Best practices are often based on the assumption that you know what the code should do

If you know exactly what you want to build then best practices and patterns can help you, by giving advice on how to build it.

But if you don’t know yet what the program should do, or what it will look like in four weeks, then some best practices can make things even harder.

Some practices are the best when applied to a rewrite, but the worst when you’re still exploring.

Using other people’s code is not as good as I thought

I started my career writing Ruby and JavaScript, with package managers being available and the question “isn’t there a package that does that?” always hanging in the air.

Common sense dictated: if you can, try to use a library instead of writing it yourself. Reuse code as much as you can. Don’t reinvent the wheel. Don’t copy & paste. That was what I believed for years.

But there are downsides to that. Sometimes writing that one function yourself might actually be better than adding a dependency.

Dependencies aren’t free. You have to keep them up to date. They increase your compile or loading times. They add strange things to your stack traces. And very often they do more than what you need them to do, which means you’re paying for more than you’re getting.

When you’re glueing other people’s code together, there’s a very real danger that the glue is where complexity will accumulate. But glue code is the last place where you want your complexity to live. It hides complexity. What you want is to make complexity as visible as you can, shining a light on it with the hope that it turns into dust and disappears.

Sometimes it’s better to write it yourself than to use other people’s code.

Some companies get it, others don’t. But nobody’s perfect

There is a big difference between developing software for a software company and developing software for a company that employs software developers because it has to. It’s a joy to work for a company in which leadership gets software and how it’s made.

That being said: I don’t think any company has it all figured out. Everybody’s winging it to some degree.

Investing in feedback loops is never wasted effort

I’ve never regretted improving a feedback loop. Faster tests, better test output, faster deploys, turning a manual feedback loop into something that gives me a signal with one keybinding.

Watch out, though: once you’ve seen the light of developing software with a really fast and high-signal feedback loop, you’ll long for it forever.

Always leave something unfinished at the end of the day

A failing test, a compiler error, a half-finished sentence – end your day with one of these and the next morning you can sit down and continue where you left off, skipping “hmm, what should I do today…” entirely.

There’s nothing that gets me started as fast as a failing test that needs to pass.

Perfectionism is a trap

Perfectionism is based on a lie. You’ll never get to the point where you’re done and sit and rest and say “ah, now it’s perfect”. There’ll always be something. You know it, I know it. There’s no perfect (see above). Accept it and ship and continue building.

Aim for 80% and consider the other 20% optional. It’s freeing and gives you room to breath. You might end up at 99%, who knows?

Sharpen the axe

I’ve gotten a lot out of investing in my tools: Vim, git, shells, the Unix environment, testing frameworks. I truly enjoy spending a Sunday morning with my Vim configuration.

But it’s possible to overdo it and get stuck in the configuration phase, doing endless tinkering. You have to use your tools to get feedback on how to best configure and use them.

Hiring is hard

I’ve done hundreds of interviews now and the most important insight I’ve gained is that hiring is really, really hard. The verdict on an interview has so many random inputs that it makes everything between a Strong Yes and Strong No wobbly.

Often I wish there was a way to find out whether people have the get-shit-done gene.

The most important trait in developers: rolling up their sleeves because it has to get done

Here’s something that all the people I enjoyed working with have in common: they do the work. They know that some tasks aren’t fun or glamorous or interesting. But someone has to do them, so they do them.

Work on a codebase with other people over a longer period of time

Nothing has helped me get better at software engineering as much as working with a group of other people on the same codebase over multiple years.

You’ll see how decisions play out.

You’ll see what ended up mattering and what didn’t.

You’ll see how extensible your code truly is when your colleague tries to modify it 3 years after you wrote it.

You’ll see whether your prediction of “we have 2 of these now, but I’m sure there’ll be 5 in the future” will come true or not and can take the outcome into account when doing other predictions.

You’ll regret writing some code and you’ll be happy that you wrote some other code. You’ll learn from reflecting on the difference between the two.

You’ll see tooling break down just because something somewhere changed and you had nothing to do with it but you still have to fix it.

You’ll say “I’ve never had to think about this in 3 years” about some pieces of software and cherish them.

You’ll see what parts of the codebase new colleagues struggle to understand and which parts they immediately get productive in.

You’ll see what the code you wrote looks like 4 years later.

Knowing the full stack

There’s few things as motivating to me as hearing “you don’t really need to know how it works…”

Sure, I might not need to, but I wouldn’t do the work I do today if I hadn’t tried to find out how a GC works, or how Unix works, or how multi-threading works, or how a database stores data, or how interpreters and compilers work.

It benefits the work I do, too. I can make better technical decisions by being able to weigh trade-offs more accurately, knowing what goes on under the hood.

Typing can be the bottleneck

I’ve said it before. Don’t let typing be the bottleneck.

Code reviews aren’t waterproof

For the longest time I assumed it’s my fault when a bug made it through one of my code reviews. I missed that! How could I have missed that? It’s so obvious!

Later I found out that it’s not just me: other people miss bugs in code reviews too. In fact, they accept and freely talk about how code reviews aren’t infallible. I was relieved.

It changed how I see code reviews: as something imperfect, something that needs to be combined with other ways to verify the code.

Not every code review is worth the effort

Not every code needs a really thorough review. Sometimes, if the risk is acceptable, it’s fine to drop a quick “LGTM!”. It unblocks your colleagues, keeps momentum and, somehow, builds trust.

Negativity begets negativity

The more you give in to negativity, the more you get. Always much more than you wanted.

It’s viral. It starts with snark, it turns into cynicism, it then morphs into “everything sucks”. Soon after, the question of “why even bother?” starts to attach itself to everything. It ends with people hiding excitement and joy and ideas from you.

Being negative is too easy. At a certain point I realised that pointing at things and saying what’s bad about them and shrugging because, well, didn’t I expect this to be bad (everything’s bad, right?) - that’s easy. Easy to do and easy to mistake for an engineering mindset that can spot deficiencies and worst cases (which it is not).

What’s hard is seeing things for what they could be, what’s beautiful about them. Encouraging ideas even when they’re barely something to talk about. Creating and fostering joy. That’s challenging.

So at some point I decided I had enough and tried to do the challenging thing. So far it’s served me well.

Every dial at 100% all the time doesn’t work

I can’t do everything equally well all the time. I can’t write a book and make progress in my career and be a great father and set PRs in the gym and read two books. It won’t work for more than one or two weeks. It’s not sustainable.

Now I let my interests take turns: when I want to make progress on a specific thing, I focus on that for a while and accept that the other things have to go into maintenance mode.

Code has mass

Code has mass. Every additional line of code you don’t need is ballast. It weighs your codebase down, making it harder to steer and change direction if you need to. The less code you need, the better.

Code has to be read, it has to be tested, it has to be kept compatible, it has to stay secure, it has to keep working. Even if it’s not doing any useful work. It doesn’t hurt having it around, does it? Yes, it does. Delete it and move on. If necessary, restore from version control.

The same is true for tests, which I’ve only learned too late.

Programming as a part of my life

Ever since I started as an intern I spent a considerable amount of time outside of work on programming: reading technical books, writing books, working on sideprojects, writing blog posts, giving talks, traveling to conferences, learning new languages and tools.

That some companies don’t care about your college degree if you can demonstrate that you’re really good at programming was fuel for me for years.

I enjoy spending time on programming outside of work, but not all the time. Some of it feels like work. It takes effort to read some technical books. But some things don’t have to feel good while you’re doing them.

My career would be completely different if I had only programmed and learned about programming at my day job.

Computers are fast

Building web applications made me think that 100ms is fast and that 50ms is really fast. Writing a compiler has taught me that 1ms is an eternity for a modern computer.

I still love programming very much

Some of what I wrote can be interpreted as me having grown cynical over the years. I mean: nothing matters and perfection is unachievable? Come on.

But it’s the opposite. I still care. I care very much. But I care about fewer things and I still love programming very much.