Klack
Klack is a beautifully crafted Mac app that adds realistic mechanical keyboard sounds to your typing. Each key is mapped with unique high-quality audio - often over 100 sounds per set, for both press and release, delivering an incredibly tactile and lag-free experience. It runs fully offline, requires no setup, and feels instantly satisfying out of the box.
Get to know Klack
Who’s behind Klack?
I’m Henrik - maker of Klack and Alcove. I actually started really early, coding in QBasic when I was around 13 and making turn-based question games. I got so obsessed with it that I developed a twitch in my eye, which turned out to just be eye strain. I used to play a lot of games, especially an MMO called Lineage. There was a design competition in the game, so I downloaded Photoshop and gave it a shot - somehow, I won.
That’s when I started thinking maybe I was good at design. That’s pretty much how coding and design both started for me. I leaned more into design after that, it came naturally, but I still wanted to build things. I was relying on a dev who kept disappearing for months, which just didn’t work for the kind of ambitious projects I wanted to make. So at 16, I started teaching myself to code. I didn’t follow the traditional route - no tutorials, no courses. I just went straight to the code, tried things, broke stuff, fixed it, and iterated. That’s how I learn best. Tutorials don’t really teach you to solve problems - they give you answers, but you never figure it out yourself. And if you can’t do that, you’re stuck building what’s already been done.
Since then, I’ve always been creating. In the beginning, I didn’t really have end goals - every project had massive scope creep. My first real project was a web armory for Lineage, where you could view your in-game items on a forum. It actually worked, and we sold a few copies. After that, everything was infinite scope and never completed. Then I pivoted to open source for a while. I worked quite a bit on Hyper Terminal — that’s also when I met some of the people now at Vercel. Back then, it was Zeit, and it wasn’t even a company yet, just a group working on open source. I wasn’t part of the Next.js stuff, but I helped out with Hyper. It wasn’t my project - it was Guillermo’s - but I was involved for a while.
Eventually, I changed my focus. I did iOS dev for companies for a while, but nothing of my own. Then I started working on a SaaS called Quill. You might’ve seen it on Twitter. It’s shut down now - the scope was too big, but I spent years on it. It was a way to build beautiful, interactive landing pages really easily. The idea was that if someone made a great app and didn’t know how to market it, they could use Quill instead of hiring someone for $20k to build that kind of site.
What’s Klack and what’s so cool about it?
Klack actually started as a side thing. I had been working for years on a SaaS product called Quill, which was meant to help people build really beautiful, engaging, interactive landing pages, without needing to hire someone or spend $20k on a custom site. The idea was that someone could make a great iPhone app but have no clue how to market it, and Quill would make it super easy to create a high-quality website.
Funny enough, Klack was originally just a demo app for Quill. I needed something real to showcase the product - it didn’t feel right to build a fake app, so I made something simple and fun: Klack. I never planned to take it seriously, but I ended up loving it more than expected. It was fun, it worked well, and I just kept pushing it further. When I first launched it, I genuinely thought no one would care. I remember thinking I probably wouldn’t even make back the $99 Apple dev fee. I was cutting every possible cost - using Cloudflare for free email forwarding, free hosting, because I fully expected zero revenue. But it turned out to be the opposite. It actually became bigger than Quill.
One of the most impressive and technically challenging aspects of Klack is the audio engine. From the start, the goal was to make it feel instant, with zero perceptible lag, which is incredibly hard to achieve when you’re working with this level of audio complexity. Unlike other apps that just play one sound across the keyboard (which is relatively easy), Klack assigns a unique sound to every single key, and in many cases, two sounds per key, for both the press and the release.
That adds up fast. Most keyboard sound sets in Klack contain over 100 high-quality sound files, and some even go beyond that - up to 150+ per set, depending on the recording. Making sure all of those sounds load quickly and play back with almost no latency was a huge challenge, and probably Klack’s biggest technical achievement.
A fun example is the Flurples keyboard, which was inspired by a viral cardboard keyboard with over 30 million views on YouTube. The original creator made it for fun, and it doesn’t even include all the standard keys, but the sound was so unique that it had to be part of Klack. After over a year of back-and-forth, a custom recording was commissioned, paid for, and integrated into the app. It’s one of the few sound sets that only exists inside Klack - you can’t get that keyboard anywhere else.
Klack has been really well received. It was featured in Forbes, 9to5Mac, and MacRumors - all completely organically. Funny enough, I didn’t even know about the Forbes feature until someone sent it to me a year later.
Tool Stack of Klack
What’s under Klack’s hood? Which technologies were used and why did you chose them?
The original prototype of Klack was actually built in Electron. At the time, it felt like a quick way to get something up and running - I wasn’t planning to release it as a real product. But the performance tradeoffs were just too much. The RAM usage was ridiculous, and the file size ballooned to over 250MB for something that should’ve been a fraction of that. It felt wrong for what I wanted Klack to be - a tight, responsive utility app, so I scrapped it.
I ended up rebuilding the whole thing from scratch in Swift, even though I’d never made a Mac app before. I’d worked in Objective-C way back, and Swift was completely new to me, but it clicked pretty fast. I spent a lot of time polishing every detail, making sure the app felt exactly how I’d want it to feel if I were the one installing it on my own Mac. That’s always been my benchmark.
I tend to keep my tools and stack pretty bare-bones, it just makes everything easier to maintain. For Klack, going through the Mac App Store was non-negotiable. Apple handles licensing, which is perfect for something that asks for full keyboard access. People need to know it’s safe. Klack sends zero data, stores nothing - it’s completely radio silent. Not even crash reports. That was super intentional. I needed to be 100% sure users could trust it.
For database management, I’ve been using Postico on the Mac. It honestly looks like something Apple would’ve built themselves. It’s beautifully done, really polished. Only downside is the price, and I get the sense the market for it is pretty niche, but I love it anyway.
Do you use any other tools to run the business?
Right now, I’m mostly using a custom setup, but I still think Xcode is one of the most well-designed pieces of software out there. Klack’s internal code editor, for example, was heavily inspired by it. Very focused, clean, and powerful. You can even run scripts inside it - super useful for quick automation.
I’ve always loved Sketch - it’s native, clean, and just feels right. I get why people love Figma, especially for web design, but it’s not native. The one big benefit is that what you design is already in the browser, so it looks the same when you ship it. With Sketch, I’ve had perfect vectors break the moment they hit the web. But since I work solo, I don’t need collaboration tools, so I still stick with Sketch.
That said, I rarely do mockups. I usually go straight into code - it’s faster, more accurate, and I know exactly how it’ll look. With design tools, things often seem right in theory but fall apart in practice. When I built Klack, I actually had to go back and create designs later, just for the promo material.
Vue and Vite is my go-to frontend stack for web-based projects. Super beginner-friendly, but also scales up to professional-level work. Everything about it is clean and well thought out. I used React in the past, like when building Hyper, but it always felt like I was working against it. Vue just feels more elegant.
What’s your personal stack? Which apps do you and your team love?
My editor of choice for web dev is Nova. It’s native, lightweight, inspired by Xcode, and lets me run scripts and manage projects cleanly. Not as popular as VS Code, but I love it. Project management all runs through GitHub Projects. Everything goes through there - issues, releases, changelogs. I can’t manage it from my phone though, so I just text myself notes when I’m out. I use Arc as my main browser. It’s not perfect, but being able to switch between app workspaces -Klack, Alcove, etc. - is a huge plus. Chrome used to make me feel like I lost half my life when tabs disappeared.
For email, I switched from Gmail to iCloud Plus - it’s simple, just works, and only a few bucks a month. I also tried Minestream, which is gorgeous and built by an ex-Apple dev, but it only supports Gmail. For window management, I use Magnet, and I actually took some UI cues from it when designing app permissions. Loop and Sleeve were also big inspirations - especially for Alcove.
In general, I get inspired by many tools. I really believe that everything is a iteration, but if you understand why something works and repurpose it intentionally, it becomes its own thing. I think it's the best way to do stuff, and I think that Steve Jobs really understood this.
Anything else you’d like to share?
I’m currently working on my third app, Pling, which will tie into Alcove and Klack as part of a growing ecosystem of carefully connected, purpose-driven tools. Until then, check out Klack - it’s fast, offline, and super addictive.
Now, discover Klack for yourself
Huge thanks to Henrik for sharing the story behind Klack and the details on the building blocks that make it such a great tool. Now go install it yourself and make your typing more satisfying then ever before.