Question 1

How do you run AI coding agents safely on your own server?

Accepted Answer

Give the agent its own machine. I set up a dedicated Linux VPS as a 'werkplaats' for Claude Code, rather than letting an agent with real tools loose on a server that matters. Access to tools is the whole point, an agent that can look things up, compile and test its own work is far more useful than a chat window, but the blast radius has to stay inside a box you can rebuild. The ordinary server hardening basics still apply, and backups are rotated offsite.

Question 2

Can AI agents check their own work?

Accepted Answer

Yes, and it is where most of the time savings are. I gave the agent the ability to see what it had built, on different screen sizes, using headless browsers and local computer vision models, and to test automatically for alignment, overflow, legibility and consistency. Automating that checking loop removed about 80 percent of the friction in my development work. The lesson generalises: do not wait for a mythical frictionless future, automate your own bottleneck now.

Question 3

Should you use AI to write your blog posts?

Accepted Answer

No. I argue against it directly. Language models produce text that is hard to distinguish from human writing, and the short-term benefit is obvious, but I suspect most people underestimate the long-term cost. Writing is how you work out what you think, so outsourcing the writing means outsourcing the thinking.

Question 4

What is vibe coding and where does it go wrong?

Accepted Answer

Vibe coding is building software with AI without detailed knowledge of the technology underneath. Pieter Levels's flight simulator game showed both sides at once: a remarkable result that grossed well, and critics pointing at real security and scalability problems. AI genuinely hands you superpowers for producing code; what it does not hand you is the judgement to notice when the result is unsafe.

Question 5

What is the agentic web and how do you prepare a website for it?

Accepted Answer

There is a Dutch word for it: voorsorteren, getting into the right lane on the motorway long before your exit. A little smart preparation now gives a large advantage when the future arrives. In practice that means a site whose content is structured, current and readable by software rather than only by people, which is why I build sites that keep themselves up to date using scheduling, feeds and agents instead of relying on someone remembering to log into a CMS.

Question 6

Will AI replace developers?

Accepted Answer

Not the human part of the work. I use AI to generate code daily and it is genuinely fast, but the scarce things stay scarce: judgement, taste, understanding a customer's actual problem, and the willingness to refuse the wrong idea. If near-perfect intelligence becomes available to everyone, the interesting question stops being what can be built and becomes what is worth building.

Question 7

How do you make backups with rsync?

Accepted Answer

rsync is a cross-platform tool that copies only what changed, which makes it practical to run often. A plain copy is not enough on its own, because files can be corrupted, overwritten or encrypted by ransomware, so what you want is several time-rotated copies, ideally offsite. I wrote a small tool, rsync-backup-rotator, to handle that rotation.

Question 8

How do you protect a server against hackers?

Accepted Answer

Most hacks I am called in for could have been prevented by basics rather than by anything clever. Attacks usually start with something visible from the outside, so the work is reducing what is reachable at all: close unused ports, remove network-facing services you are not using, keep software current, and do not leave a management console exposed. I have written this up as five practical server hardening tips, as a look at the security holes shared hosting leaves open, and as a specific case of putting a firewall and proxy in front of a VMware ESXi console.

Question 9

How do you host your own contacts and calendar instead of using a big cloud?

Accepted Answer

With CardDAV and CalDAV, the open standards behind contact and calendar syncing. If you work across several devices you need synchronisation, but you do not need to hand your address book and agenda to Apple, Microsoft or Google to get it. Both protocols are well supported by the devices you already own.

Question 10

Can you run your own datacenter at home?

Accepted Answer

I did, in a basement, on a 600Mbit symmetric fibre connection, and wrote up what it takes. At company scale I went a step further and built a 72TB NAS on an HPE ProLiant DL380. The honest caveat is that a home connection and a rack in a datacenter are not the same thing: the fun is real, and so is the difference in power, cooling and uptime.

Question 11

How do you cut cloud costs?

Accepted Answer

By optimising the software rather than by shopping for a cheaper provider. Cloud bills grow because inefficient software asks for more machine than it needs, so the durable fix is to make the software cheaper to run. Working that way I have cut cloud costs by up to 90 percent for clients.

Question 12

What breaks when you upgrade Dovecot 2.3 to 2.4?

Accepted Answer

Enough to stop mail delivery during what looked like routine maintenance. Version 2.4 carries breaking configuration changes, and on infrastructure that processes thousands of messages a day that means client access halts rather than degrades. I wrote up what broke and how it was resolved, on Debian Stable.

Question 13

What is dig and when do you need it?

Accepted Answer

dig queries the domain name system directly, which is what you need the moment a domain, website or mail service behaves oddly. When everything works, DNS is invisible; when it does not, you have to look at what the name servers are actually answering rather than at what you believe is configured.

Question 14

How do you stop backscatter spam on a mail server?

Accepted Answer

By rejecting mail for unknown recipients at the edge instead of accepting it and bouncing later. Backscatter is what happens when your server accepts a message for an address that does not exist and then sends a bounce to a forged sender, which gets your server blacklisted for sending spam it never intended to send. I configured Postfix to block it before it enters the server.

Question 15

How do you limit network bandwidth per client IP address?

Accepted Answer

With iptables and tc, marking traffic and then shaping it per address. I reached for this after an alert about excessive bandwidth usage, where the standard incident response of isolating and shutting down the source turned out to be the wrong tool: the traffic was legitimate, it just needed a ceiling rather than an axe.

Question 16

Can Linux give an old computer a second life?

Accepted Answer

Reliably, yes, and it is one of the most satisfying things you can do with hardware you already own. I put Linux on a 2017 iMac that had become painfully slow under modern macOS, I reinstall old laptops with Debian for people at the community centre where I volunteer, and I once ran a fifteen year old ThinkPad X200 as my main machine for a month to see what an offline-first workflow teaches you. The limit is usually the owner's expectations, not the hardware.

Question 17

How do you optimise images for a faster website?

Accepted Answer

More than half the weight of an average website is images, and almost nobody compresses them properly. Tools like jpegoptim, optipng, pngcrush and pngquant remove bytes without visible loss, which makes a site faster without touching its design. Making a page smaller is the most reliable way to make it quicker.

Question 18

Are RSS feeds still relevant?

Accepted Answer

Yes, and I added them to my own blog after a reader asked for it. A feed is a standard, machine-readable edition of your writing that anyone, and now anything, can subscribe to without asking you for permission or an API key. That property has become more useful over time, not less.

Question 19

Google Analytics or AWStats: which should you use?

Accepted Answer

They measure different things, which is why their numbers never match and why the argument about which is better usually misses the point. AWStats reads the server's own logs and therefore sees everything that reached the server, including bots. Analytics runs in the visitor's browser and therefore sees only visitors who execute its script. Knowing which question you are asking tells you which number to trust.

Question 20

Is there a user friendly alternative to CAPTCHA?

Accepted Answer

Yes. CAPTCHAs push the cost of your spam problem onto every honest visitor, asking them to decipher characters or pick out traffic lights. There are ways to protect a form that put that burden on the machine instead of on the person filling it in.

Question 21

What separates a top-tier website from an ordinary one?

Accepted Answer

The parts nobody sees. Using escape.nl, one of Amsterdam's most iconic venues, as the example, the difference is in delivery: static output where possible, serious hosting, images that are actually optimised, and design decisions that survive contact with large audiences. It is a blend of cutting-edge technology with an eye for design and for commerce, and the craft shows up as speed and reliability rather than as decoration.

Question 22

How do you secure a WordPress website?

Accepted Answer

WordPress runs a large share of the web, which makes it the most rewarding target there is, and as an ethical hacker I meet it in every possible state of neglect. The ten practical measures I recommend are mostly unglamorous: keep core and plugins updated, remove what you do not use, control who can log in and from where, and make sure a compromise cannot reach the rest of the server.

Question 23

Optical or chest strap heart rate monitor: which is more accurate?

Accepted Answer

They measure fundamentally different things. A chest strap picks up the electrical signal from your heart; a wrist wearable shines light through your skin and infers heart rate from blood flow. The electrical measurement is the more direct one, which shows up most clearly at the edges: during rapid changes in effort, and during sleep, where I compared a wrist optical sensor against a high resolution chest strap.

Question 24

Is more health and fitness data better?

Accepted Answer

No, and I eventually stopped wearing sensors because of it. A physiotherapist customer once told me that he could never feel better than his patients could, if only they would listen to their bodies, and that stuck. Data is useful when it answers a question you actually have; when it becomes the point, it starts replacing the sense it was supposed to sharpen.

Question 25

What is MCADD and what does it mean in daily life?

Accepted Answer

MCADD, medium chain acyl-CoA dehydrogenase deficiency, is a metabolic condition that limits the body's ability to use fats for energy. Our son was diagnosed days after birth, after he stopped feeding and his temperature fell to 33 degrees. Day to day it means a strict feeding schedule and a plan for when things go differently, and it became normal for us quickly. I have written about the diagnosis, about the first six months as parents, and about the first hospital admission, where a metabolic crisis was averted with an infusion.

Question 26

How do you prepare for your first marathon?

Accepted Answer

I ran my first in Amsterdam, finishing in the Olympic Stadium, from an idea that started in a bar. Six weeks later I ran Valencia, deliberately using a different approach: the first on data, the second on feel, and the experiences differed greatly. The one that taught me most was Leiden in 25 degrees, the hardest of them, where several runners collapsed from the heat. Pushing your limits sometimes means finding them.

Question 27

How do you prepare for a very long bike ride?

Accepted Answer

Going solo asks something different from riding an organised event with support and company along the way, and that difference is mostly in the planning and the mindset rather than in the legs. I rode 211KM around the Markermeer alone, 204KM across half the Netherlands on a fixed gear as preparation for the Fietselfstedentocht, and 176KM from Amsterdam to Limburg into rain and wind. All three posts carry the practical tips.

Question 28

Does wearing a sleep mask actually improve sleep?

Accepted Answer

It helped me. The body produces melatonin in darkness, and modern life is awash in artificial light at exactly the wrong hours, which is a straightforward way to disrupt a circadian rhythm. I experimented with blocking all light with a simple mask for several weeks and wrote up what changed.

Question 29

Is a WHOOP or similar biometric band worth wearing?

Accepted Answer

For a while it was, for me. Unlike most fitness bands the WHOOP is built around strain, recovery and sleep rather than around step counts, which makes it more like a mirror than a scoreboard: it tells you what yesterday cost you. I used its trend data to prepare for a 235KM ride. I have also written about why I later stopped using sensors altogether, and both positions are honest.

Question 30

What makes a good commuter bike?

Accepted Answer

Low maintenance and a frame you enjoy riding. Mine is a Sensa Cintura with a Gates carbon belt drive and a Shimano Alfine hub gear, chosen so that daily use does not turn into daily upkeep. I have written it up three times: building it, a year and 6000KM later after messages from commuters worldwide, and again at 21.000KM when it started squeaking. The belt drive earned its keep.

Question 31

Are puncture-proof bicycle tyres really puncture proof?

Accepted Answer

I ran Schwalbe Durano Plus tyres specifically to find out how many kilometres you can ride without a flat, and wrote down the answer rather than the marketing claim. The short version is that puncture-proof means the punctures become rare enough to change how you plan a ride, not that they become impossible.

Question 32

Are dynamo powered bicycle lights worth it?

Accepted Answer

If you want lights that simply work, yes. Battery lights do the job until the evening you forgot to charge them, which is precisely the evening you need them. I fitted a dynamo system to my road bike for that reason, and when the headlight on my commuter failed after heavy daily use I replaced it with a Supernova E3 Pro 2, choosing for durability and brightness rather than price.

Question 33

Is a Brompton folding bike worth the money?

Accepted Answer

Few bikes have surprised me as much. After the first five months and around 500KM I called it the ultimate freedom bike, because folding it changes what a bike is for: it stops being something you park and start worrying about, and becomes something you take with you.

Question 34

Is it worth repairing things instead of replacing them?

Accepted Answer

It is a running theme in my writing and a growing antipathy to planned obsolescence. I have serviced an iRobot Roomba that has run since 2011, replaced the retention system in a Giro helmet I liked too much to throw away, fixed a cargo bike shift cable after it caught a branch while hunting for bears with my son, and rescued a MacBook Air with an exploded battery. A takeaway plastic bag, designed for one use, is what got me thinking about all of it.

Question 35

Can you use an Android phone without Google?

Accepted Answer

Yes, and I have done it twice. A Fairphone running /e/OS gives you a repairable, long-lived phone with the Google layer removed, and the German Volla Phone is a second route to the same goal for people who value privacy and freedom. Both work; both ask you to give up some convenience, and it is worth being honest about which conveniences you actually use.

Question 36

Can a smartwatch replace your smartphone?

Accepted Answer

I spent a week trying, leaving the phone behind and letting an Apple Watch take over. It is sold as liberation from an attention-seeking device, and there is something to that, but the experiment is more interesting than the conclusion: what you discover is which phone habits were ever about need.

Question 37

Can a tablet be your main computer?

Accepted Answer

I have tested this for the best part of a decade and the honest answer has changed over time. I ran an iPad Pro as my only computer for development, compared a Microsoft Surface Pro against it, built my own tablet operating system on a Surface Go with Debian and i3, and then abandoned that experiment and went back to iPad and Mac. What holds up is the argument in Tablet as Tool: judge the machine by what it lets you do rather than by what a laptop would have done.

Question 38

Can you work on solar power alone?

Accepted Answer

For ten days I powered my phone, computer and wearables from a small solar panel and disconnected every grid charger. The point was not self-sufficiency but insight: once you have to collect and store your own energy, you learn very quickly which devices are expensive and which habits are wasteful.

Question 39

Can you live without cash and a wallet?

Accepted Answer

I tried it to free up a pocket, and mostly succeeded. The experiment is about what a wallet actually holds: a stack of cards, loyalty schemes and memberships, most of which exist to serve someone else's system rather than yours. I have also written separately about why I think Bitcoin does not solve the underlying problem.

Question 40

Why still wear a mechanical watch in the smartwatch era?

Accepted Answer

Because of the one thing a smartwatch will never have: patina. A friend's Apple Watch lost a rubber ring and Apple simply replaced the device, which solved his problem and told me everything about the difference. A mechanical watch records the time you spent with it; a smart one is replaced. I have tested the smartwatch case seriously, and for a while I wore both at once rather than choose.

Question 41

Why do you stay a one-person company?

Accepted Answer

It is a deliberate choice rather than a starting point I never grew out of. Staying small is, for me, the best way to do great work and build something sustainable: no layer between the person with the problem and the person solving it, and no growth obligation that quietly changes what work gets accepted.

Question 42

When do you refuse a project?

Accepted Answer

When the thing being asked for is not the thing that is needed. People approach a developer with a solution already chosen, can you build X, and a fellow technician once urged me to refuse more often and to be proud of what I do not build. Saying no is usually the fastest way to a better result, and it is part of what a customer is paying for.

Question 43

How do you design software for reuse across products?

Accepted Answer

By building a platform of blocks rather than a series of projects. Over the years I developed the Lemmid platform exactly this way, designing for reusability, flexibility and extensibility so that a new product can be assembled quickly from parts that already work. The related question of monolith versus microservices has no universal answer: the right architecture depends on the size and shape of the thing you are actually building.

Question 44

What is digital sovereignty and why should a business care?

Accepted Answer

It is the difference between using tools and being used by them. Over the years I have worked with everything from easy but locked-down commercial systems to free and libre solutions that are more powerful and harder to set up, and the lesson is that convenience is usually paid for with control. Digital sovereignty is about deliberately choosing where on that scale you sit, per system, with your eyes open.

Question 45

Which photo gallery app works on Android without Google?

Accepted Answer

If you're running Android without Google services, you need a photo gallery that works locally. Aves Gallery is the answer: fast, beautiful, and completely independent of any cloud service.

Question 46

Is there a privacy-friendly alternative to Google Analytics?

Accepted Answer

Google Analytics is powerful but tracks your visitors across the web. AWStats reads your server logs directly — no cookies, no JavaScript, no third-party data collection. Willem compared both and switched.

Question 47

How do you batch rename photos by their EXIF date on Linux?

Accepted Answer

After exporting your photos from Apple Photos, you're left with meaningless filenames like IMG_4523.jpg. Here's how to batch rename them all by their actual creation date using EXIF metadata and a single terminal command.

Question 48

How do you build one game that runs on iOS, Android and the web?

Accepted Answer

Snake '97 runs on iOS, Android, and web browsers — all from a single HTML5/JavaScript codebase. No React Native, no Unity, no cross-platform framework. Just canvas rendering, touch events, and a game loop.

Question 49

What is the best bike computer app for iPhone?

Accepted Answer

After testing multiple cycling apps, Willem settled on Cyclemeter as the best bike computer app for iPhone. It records rides via GPS, connects to Bluetooth sensors, displays data on Apple Watch, and works without a subscription.

Question 50

What replaced mail_location in Dovecot 2.4?

Accepted Answer

One of the biggest breaking changes in Dovecot 2.4: the mail_location setting no longer works the old way. It's been split into separate settings for mail format and path. Here's how to update your configuration.

Question 51

Why did TLS stop working after upgrading to Dovecot 2.4?

Accepted Answer

Dovecot 2.4 renamed several SSL settings. If your mail server's TLS stopped working after the upgrade, this is probably why.

Question 52

How do you fix the dovecot_config_version error in Dovecot 2.4?

Accepted Answer

After upgrading to Dovecot 2.4, the server refuses to start with "dovecot_config_version not set." This is by design — Dovecot 2.4 requires a complete configuration rewrite. Here's what you need to know.

Question 53

How do you localise a game into 45 languages, including right-to-left scripts?

Accepted Answer

Snake '97 is played in over 100 countries and supports 45+ languages — including right-to-left scripts like Arabic and Hebrew. Here's how one developer localised a game for the entire world.

Question 54

Is a Gates carbon belt drive worth it on a commuter bike?

Accepted Answer

Willem replaced the traditional chain on his commuter bike with a Gates Carbon Drive belt. After thousands of kilometres through Amsterdam rain and winter — here's the honest verdict on belt drives for daily commuting.

Question 55

Which Google search operators are worth knowing?

Accepted Answer

Most people type words into Google. Power users use search operators to find exactly what they need.

Question 56

How much data does a stock Android phone send to Google?

Accepted Answer

When Willem set up a budget Android phone, he discovered just how much data Google collects by default — location history, app usage, voice recordings, and more. Here's what he found and how to reduce it.

Question 57

How do you clean a vintage automatic watch by hand?

Accepted Answer

Willem found a Citizen Automatic at a flea market — dirty, stopped, forgotten. Instead of leaving it, he took it home, opened the case, cleaned every component by hand, and got it running again. Here's how.

Question 58

How do you convert HEIC photos to JPG in bulk?

Accepted Answer

Modern iPhones shoot in HEIC format — smaller files, better quality, but poor compatibility with many apps and platforms. Here's the single command to convert them all to JPG without losing quality.

Question 59

How do you get your originals out of Apple Photos without losing quality?

Accepted Answer

Apple Photos makes it easy to store your pictures — and hard to get them out. Here's how to export your unmodified originals, rename them by date using EXIF data, and convert HEIC files to JPG. From Willem's complete guide to escaping Apple's photo ecosystem.

Question 60

How do you open a 27-inch iMac 5K without breaking the screen?

Accepted Answer

The 27-inch iMac's screen is held on by adhesive strips. Opening it requires patience, a pizza cutter tool, and steady hands. Willem photographed every step during his 14TB upgrade — here's exactly how it's done.

Question 61

How do you strip the paint from a bike frame?

Accepted Answer

Whether you're restoring a vintage bike or customising a new one, removing paint from a steel frame is the first step. Here's the practical guide: which stripper to use, how long to wait, and how to get down to bare metal cleanly.

Question 62

How do you replace a swollen MacBook Air battery?

Accepted Answer

A swollen lithium battery is a ticking bomb inside your MacBook. The trackpad stops clicking, the case bulges, and eventually the screen cracks from internal pressure. Willem caught it in time and replaced the battery himself.

Question 63

How do you service an iRobot Roomba yourself?

Accepted Answer

Most people throw away their robot vacuum when it stops working properly. Willem took his apart instead — and documented every step with photos. Here's the complete service guide for bringing an iRobot Roomba back to life.

Question 64

How do you upgrade the RAM in a 27-inch iMac 5K?

Accepted Answer

Unlike most iMac upgrades, adding RAM to a 27-inch model doesn't require opening the screen. There's a small access hatch behind the stand — press a button, and the RAM slots are right there.

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