almost done

lossifier

hello@nietaki.com (nietaki) — Fri, 10 Apr 2026 00:00:00 +0000

A dockerized script for converting a FLAC music library to a lossy Opus/MP3 format making maintaining an offline music collection easy.

nietaki/lossifier

converts your lossless .flac music collection to a mirrored .opus or .mp3 collection

Creative Coding

hello@nietaki.com (nietaki) — Fri, 10 Apr 2026 00:00:00 +0000

A while back I was looking for a creative outlet I could make something I’d like on a daily basis and (finally) got into creative coding.

I chose love2d as my framework and started making animations, aiming to create a new one on a daily basis.

As I built up my lua toolkit the creations got more complex over time, with 3d rendering, a custom GLSL pre-processor and tracing profiler.

Revolt keyboard

hello@nietaki.com (nietaki) — Fri, 10 Apr 2026 00:00:00 +0000

After using ergonomic keyboards for over a decade I designed one that’s close to perfect - not for most, but definitely for me.

nietaki/revolt-keyboard

Epstein Roulette

hello@nietaki.com (nietaki) — Fri, 10 Apr 2026 00:00:00 +0000

Examine a random Epstein file from the millions that have been released. You can narrow the pool down by file type or text contents.

Another small project I wrote while teaching myself golang. It uses the Echo web framework and sqlite as the database.

Note

The logo was (obviously) AI generated, but the code was written by hand as a learning exercise, not vibe-coded.

Split Keyboard Gallery

hello@nietaki.com (nietaki) — Fri, 10 Apr 2026 00:00:00 +0000

(not just) Split Keyboard Gallery

https://splitkeyboard.gallery/

Split Keyboard Gallery - tool for browsing over 100 keyboards and filtering them by properties

A weekend project to teach myself myself Alpine.js and hugo. And to get the word about my Revolt keyboard out there.

Rexbug

hello@nietaki.com (nietaki) — Fri, 10 Apr 2026 00:00:00 +0000

A thin Elixir wrapper for :redbug production-friendly Erlang interactive tracing debugger. It tries to preserve :redbug’s simple and intuitive interface while making it more convenient to use by Elixir developers.

nietaki/rexbug

A thin Elixir wrapper for the redbug Erlang tracing debugger.

markdown-resume

hello@nietaki.com (nietaki) — Fri, 10 Apr 2026 00:00:00 +0000

nietaki/markdown-resume

A simple tool for generating good looking CV pdfs from vanilla markdown files

Ampersand Table

hello@nietaki.com (nietaki) — Fri, 10 Apr 2026 00:00:00 +0000

A kinetic sculpture in the form of an interactive coffee table. While it might not end up being commercially available, the tech side of things was a success, especially considering the bootstrapping approach in a small team. From the aluminum and 3d printed plastic mechanism I designed from scratch, through the electronics, microcontroller “brain” with some clever C++ code on it and the Flutter app that controlled it all - it all works pretty damn well and looks good in the wood and concrete package.

Raxx/Ace/Raxx.Kit

hello@nietaki.com (nietaki) — Fri, 10 Apr 2026 00:00:00 +0000

CrowdHailer/raxx

Interface for HTTP webservers, frameworks and clients

My small collection of awesome

hello@nietaki.com (nietaki) — Fri, 10 Apr 2026 00:00:00 +0000

There’s a bunch of projects that make my life a whole lot better. I can only preach about them to my friends so much, so here’s some links to spread the word otherwise.

Blowfish
#

The Hugo template I used for the latest incarnation of this blog.

I knew it was good as soon as I saw it, but the fact that it took me less than a day to move from the old jekyll blog to hugo, add some customizations without slowing down and be very happy with the results makes it just exceptional.

Owning your music (collection) without losing your mind, part 2

hello@nietaki.com (nietaki) — Fri, 27 Mar 2026 12:00:00 +0000

(part 1 here)

Now that we have a way to get our music and our player(s) picked out, let’s come up with an easy to use workflow and an organisatonial structure that works for us. It’s going to be a lengthy one, so let’s just get started.

Here’s the gist of the workflow:

flowchart TD


cd((CDs))
cd-- dBPoweramp CD Ripper -->flac

bandcamp@{ shape: cloud }
bandcamp-->flac

subgraph TrueNas
 direction TD
 flac@{ shape: documents, label: "/flac_music" }
 opus@{ shape: documents, label: "/opus_music" }
 mp3@{ shape: documents, label: "/mp3_music" }
 plex@{ shape: "lin-rect", label: "PLEX server" }
 flac-. lossifier-opus .->opus
 flac-. lossifier-mp3 .->mp3
 flac===plex
end

rb@{ shape: card, label: "rockbox DAP"}
android@{ shape: card, label: "Android DAP"}
snow@{ shape: card, label: "snowsky DAP"}
laptop@{ shape: card, label: "laptop"}

opus-- rclone -->rb
mp3-- rclone -->snow
opus-. autosync .->android
plex-->laptop
plex-->android

flowchart TD

subgraph legend [Legend]
 direction TD
 style legend fill:none
 smb@{ shape: documents, label: "SMB share" }
 docker@{ shape: "lin-rect", label: "docker service" }
 dap@{ shape: card, label: "player hardware"}
 Com@{ shape: braces, label: "dotted arrows run\n on a schedule" }
end

As you can see the centerpiece of the system is a TrueNas NAS.

Srcery cheat sheet - This should already be up somewhere

hello@nietaki.com (nietaki) — Tue, 24 Mar 2026 12:00:00 +0000

Srcery color scheme is awesome, but it’s not nearly as popular as some of the other ones. So if you adopted it as your main color scheme, you sometimes gotta do some legwork to make your devenv consistent.

So since I’m adopting Zellij, I sort of had to make this cheat sheet:

type	name	full name
primary	black	`srcery-palette-primary-black`
primary	red	`srcery-palette-primary-red`
primary	green	`srcery-palette-primary-green`
primary	yellow	`srcery-palette-primary-yellow`
primary	blue	`srcery-palette-primary-blue`
primary	magenta	`srcery-palette-primary-magenta`
primary	cyan	`srcery-palette-primary-cyan`
primary	white	`srcery-palette-primary-white`
primary	bright-black	`srcery-palette-primary-bright-black`
primary	bright-red	`srcery-palette-primary-bright-red`
primary	bright-green	`srcery-palette-primary-bright-green`
primary	bright-yellow	`srcery-palette-primary-bright-yellow`
primary	bright-blue	`srcery-palette-primary-bright-blue`
primary	bright-magenta	`srcery-palette-primary-bright-magenta`
primary	bright-cyan	`srcery-palette-primary-bright-cyan`
primary	bright-white	`srcery-palette-primary-bright-white`
secondary	orange	`srcery-palette-secondary-orange`
secondary	bright-orange	`srcery-palette-secondary-bright-orange`
secondary	hard-black	`srcery-palette-secondary-hard-black`
secondary	teal	`srcery-palette-secondary-teal`
secondary	xgray1	`srcery-palette-secondary-xgray1`
secondary	xgray2	`srcery-palette-secondary-xgray2`
secondary	xgray3	`srcery-palette-secondary-xgray3`
secondary	xgray4	`srcery-palette-secondary-xgray4`
secondary	xgray5	`srcery-palette-secondary-xgray5`
secondary	xgray6	`srcery-palette-secondary-xgray6`
secondary	xgray7	`srcery-palette-secondary-xgray7`
secondary	xgray8	`srcery-palette-secondary-xgray8`
secondary	xgray9	`srcery-palette-secondary-xgray9`
secondary	xgray10	`srcery-palette-secondary-xgray10`
secondary	xgray11	`srcery-palette-secondary-xgray11`
secondary	xgray12	`srcery-palette-secondary-xgray12`

Fixing Cloudflare 523 errors

hello@nietaki.com (nietaki) — Wed, 25 Feb 2026 12:00:00 +0000

For some context: Recently I’ve been sharpening my Kubernetes skills by setting up a small 6 node k3s cluster at home. The place I currently live doesn’t have a public IP address, so I chose to set up a Cloudflare Tunnel to expose services to the internet.

I chose to have the cloudflared daemon running on the host machines and the overall setup quick and pain-free. The whole thing seemed to work well, but I noticed that over time (within hours) the tunneled services would start responding more slowly and eventually Cloudflare would display 523 errors.

Owning your music (collection) without losing your mind, part 1

hello@nietaki.com (nietaki) — Thu, 15 Jan 2026 12:00:00 +0000

Recently, after learning how bad spotify is for its artists I made a deliberate effort to move my family to Tidal - 8/10 decision, would recommend.

But to take step further I decided to slowly move towards “owning my music” - maintaining my own digital collection of music and making sure I have a convenient way of listening to it.

There were a number of reasons for it

About

hello@nietaki.com (nietaki) — Wed, 01 Jan 2025 00:00:00 +0000

My name is Jacek Królikowski, I studied Computer Science at the University of Warsaw and worked as a software engineer at Microsoft and a number of startups (including my own) in London and Warsaw.

I enjoy having a broad understanding of engineering (software and otherwise), but I specialise in the back end side of things, especially using Erlang/Elixir. I’m passionate about functional programming, resilient system design, and using the right tool for the job at hand.

Elixir string operations seem slow (and why it's a good thing)

hello@nietaki.com (nietaki) — Fri, 21 Apr 2023 13:00:00 +0000

I personally hate it when people post clickbait titles and take their sweet time getting to the point, so let’s do this first:

TL;DR: Some Elixir string operations, most notably String.at/2 work in linear time, as opposed to constant time, like the intuition might suggest. This is because the String module is UTF-8 aware. UTF-8 encodes characters outside of ASCII with more than one byte, so in order to find the n-th character in a string you need to process it from the beginning, you can’t just use an offset in memory.

Notion Buttons and what they need to be truly useful

hello@nietaki.com (nietaki) — Wed, 12 Apr 2023 12:00:00 +0000

I’m a long time power-user of Notion. For the last couple of years I’ve been using it for all of my note-taking, work organisation and tracking, online documentation, storing cooking recipes and much more. Recently they introduced a new Buttons feature and it excited many people who thought it would be the missing piece in their workflow organisation.

I played around with it for a while and I can see the current functionality is a great starting point, but it needs a bit more to actually be useful (to me)…

How to use data spanning multiple data sources in Elixir

hello@nietaki.com (nietaki) — Sun, 02 Feb 2020 15:00:00 +0000

Below is a reprint of the article I wrote for the Rekki Medium page.

REKKI builds tools that help people along the restaurant supply chain do their jobs better.

We have a free mobile app that lets restaurants order and chat with suppliers, and a web-based tool for suppliers that helps them process orders, manage product codes and catalogues, and communicate more easily with their customers. The majority of REKKI’s backend is written in Elixir, working hand in hand with services written in Go and Node. The Elixir services handle most of what the user sees in the app like the real-time communication with the supplier and the status of the orders.

Trust issues: trouble in package paradise - Code BEAM STO 2019 talk

hello@nietaki.com (nietaki) — Sun, 01 Sep 2019 15:21:00 +0000

Earlier this year I gave a talk at Code BEAM STO about a proposed solution to the ever more real risk of hidden malicious code in our library dependencies. You can watch the whole thing here:

UPDATE: I have since dropped active development of the Hoplon project, but I hope something like it will become reality when the tech community is ready for it :)

String.to_existing_atom/1 is a double-edged sword

hello@nietaki.com (nietaki) — Tue, 04 Dec 2018 13:21:00 +0000

I’d argue Elixir has relatively few gotchas. It’s a simple and consistent language and when you first learn it there’s only a few things that are genuinely counter-intuitive and catch you by surprise.

One of the examples could be the difference between binaries and charlists and why iex sometimes seems to do weird things to your lists:

iex> l = [19, 7, 16, 119, 97, 116]
[19, 7, 16, 119, 97, 116]
iex> Enum.drop(l, 1)
[7, 16, 119, 97, 116]
iex> Enum.drop(l, 2)
[16, 119, 97, 116]
iex> Enum.drop(l, 3)
'wat'

One of the other ones comes when you start working with atoms and get a little too trigger-happy with them. What you could hear from your more experienced teammates is something like this:

I'm stealing API keys from your site

hello@nietaki.com (nietaki) — Sun, 02 Dec 2018 18:00:00 +0000

Earlier this year I presented my latest project - Hoplon - at the London Elixir meetup. I’m thinking of putting some more work into it over Christmas, so I figured I might gather the materials about it in one place:

Hoplon is an Elixir developer tool that helps you validate your dependencies contain no hidden malicious code. Motivated by horror stories from the JavaScript community such as this hypothetical one and this very real one.

Introducing Rexbug - tracing on the shoulders of giants

hello@nietaki.com (nietaki) — Wed, 10 Jan 2018 02:00:00 +0000

Towards the end of November I gave a flash talk at the London Elixir Meetup. This time I was talking about the journey from println debugging to proper tracing and bringing Erlang tools to Elixir programmers.

You can watch the talk here:

…and here are the slides:

The resulting Rexbug project is ready to be used but there’s still some issues I could use some help on - some should even be suitable for Elixir beginners.

Crawlie - Elixir London Meetup presentation

hello@nietaki.com (nietaki) — Sun, 09 Jul 2017 02:00:00 +0000

Last year, I saw José Valim give his keynote at the ElixirLive conference in Warsaw, where he talked about the motivation for his new Elixir libraries: GenStage and Flow. Even though I heard about those before, it was the keynote when I “got” what the libraries were good for and why they were neat - and I decided to play around with them.

Today I Learned

hello@nietaki.com (nietaki) — Mon, 10 Apr 2017 00:00:00 +0000

There used to be dates next to each of items - without them the “Today” makes a bit less sense 😀

pico.css
#

TIL about pico.css - the minimalistic and zero-friction CSS framework for semantic HTML.

Atom as an elixir IDE

hello@nietaki.com (nietaki) — Mon, 14 Nov 2016 20:58:00 +0000

July 2019 update:
#

I have since moved to neovim for all my Linux/OSX work, and I’m very happy with it. The information here is probably very outdated, but I’m leaving it here for posterity

You can see my neovim configuration in my dotfiles

Earlier this year I joined Mainframe as a backend engineer. I didn’t do any real development in elixir before and I wanted to become productive with it ASAP. When it comes to elixir there were some good books to help me understand it better, but I also needed an editor or and IDE that would give me the necessary tools without getting in my way.

Liar's dice (common hand) - best rules variation

hello@nietaki.com (nietaki) — Sat, 12 Dec 2015 22:00:00 +0000

I’ve been a semi-active board game nerd for quite a while now and I find myself playing a wide variety of games, ranging from Jungle Speed to Battlestar Galactica and go. Board games are a huge universe to explore, but there’s been one game that me and my friends have been playing for years now and it’s still a crowd favourite. It can accommodate virtually any number of players, it’s cheap (all you need is some dice), simple to explain, and - last but not least, drunk-people-friendly. If you can still count, you can still play and even if the table is all covered in beer, the dice couldn’t care less.

Intern's guide to Dublin

hello@nietaki.com (nietaki) — Fri, 19 Oct 2012 12:00:00 +0000

I spent the last three months in Dublin, on an internship with Microsoft. The experience was great and I could recommend it to anybody, but that’s not what I wanted to talk about this time. Whenever you move from one place to another there’s a certain amount of know-how that makes your new life easier/better/more predictable and that knowledge usually comes with time. By the end of my internship I felt at home in Dublin and now I’d like to share some tips with you.

ML-class.org course

hello@nietaki.com (nietaki) — Fri, 10 Feb 2012 12:00:00 +0000

In the last three months of the last year I had the pleasure of taking part in an online machine learning course, taught by prof. Andrew Ng of the Stanford University. The course is already over, so it might seem old news, but next edition should start any time now. If the topic of machine learning seems interesting to you in any way I can really recommend it.

TDD in C++ (screencast in Polish)

hello@nietaki.com (nietaki) — Thu, 09 Feb 2012 12:00:00 +0000

For my classes I recorded screencasts about TDD, and, because lately I’m focused mostly on c++, I decided to dive into google test instead of the regular jMock and Mockito. Initially I wanted to make it a tutorial showcasing all the tools within the library, but it ended up being a TDD Kata solving example with a short introduction about how to set up the development environment.

Google engineers meetup

hello@nietaki.com (nietaki) — Tue, 18 Oct 2011 12:00:00 +0000

This thursday, in the lecture hall of the Biology Departament of University of Warsaw, Google organized a meetup with their engineers, celebrating the official launch of their new office in Warsaw. The event started with Joshua Bloch’s, lecture, which was a treat for the attendees, most of whom were MIM UW students, almost filling the room.

Joshua presented code snippets that don’t do what you might expect them to, by invoking constructs that may lead to unforseen behavior. Majority of those constructs weren’t Java-exclusive and could have been presented in C++ or even python. The well known issues were covered, e.g. String comparison, operator precedence, working with floating-point variables, implicit conversion. But there also were topics I haven’t ever thought about, like regular expressions that match same patterns but differ hugely in their efficiency.

laptop monitoring - the aftermath

hello@nietaki.com (nietaki) — Tue, 04 Oct 2011 12:00:00 +0000

Some time ago I described a script you could use to see who’s using your laptop when you’re not around. I sadly (?) didn’t catch any robbers using it, but the whole setup already took nearly 4000 photos, some of which might be a little interesting:

I’ve got a series or two of one person sitting in front of the computer for quite some time and I could use it to create a timelapse similar to those I made using my crude blackberry app, but on the other hand maybe I shouldn’t be picking on my friends…

Next Top Coder wallpapers

hello@nietaki.com (nietaki) — Wed, 21 Sep 2011 23:24:00 +0000

I was talking to a friend of mine and we came up with the idea of “America’s next top model” and Top Coder crossover. The “top model” shows are slowly losing their popularity, but our idea is still scary on the wallpaper of my desktop, motivating me to hard work:

Half of the idea and the whole design is courtesy of Jakub Rostkowski, and the wallpaper comes in three different sizes: 1440×900, 1600×1200, 1900x1200,

defensive photobooth a.k.a Do Not Fuck With a Hacker's Machine

hello@nietaki.com (nietaki) — Sun, 24 Apr 2011 12:00:00 +0000

Some time ago, inspired by…

…also known as the “Do not fuck with a hacker’s machine” clip, and the fact I started using Debian exclusively on my netbook, I decided to make preparations in advance for a dire situation in which my laptop is stolen/captured by insurgents, and retrieve it easier or even play a prank on them. These were my postulates:

almost done

lossifier

Creative Coding

Revolt keyboard

Epstein Roulette

Split Keyboard Gallery

Rexbug

markdown-resume

Ampersand Table

Raxx/Ace/Raxx.Kit

My small collection of awesome

Blowfish #

Owning your music (collection) without losing your mind, part 2

Srcery cheat sheet - This should already be up somewhere

Fixing Cloudflare 523 errors

Owning your music (collection) without losing your mind, part 1

About

Elixir string operations seem slow (and why it's a good thing)

Notion Buttons and what they need to be truly useful

How to use data spanning multiple data sources in Elixir

Trust issues: trouble in package paradise - Code BEAM STO 2019 talk

String​.to_existing_atom​/1 is a double-edged sword

I'm stealing API keys from your site

Introducing Rexbug - tracing on the shoulders of giants

Crawlie - Elixir London Meetup presentation

Today I Learned

pico.css #

Atom as an elixir IDE

July 2019 update: #

Liar's dice (common hand) - best rules variation

Intern's guide to Dublin

ML-class.org course

TDD in C++ (screencast in Polish)

Google engineers meetup

laptop monitoring - the aftermath

Next Top Coder wallpapers

defensive photobooth a.k.a Do Not Fuck With a Hacker's Machine

Blowfish
#

String.to_existing_atom/1 is a double-edged sword

pico.css
#

July 2019 update:
#