HolidayCheck GraphQL Day
This week we had an internal GraphQL Day at HolidayCheck in the Munich office. In this article I will share with you why we did it, what we talked about...
Two questions every unit test should answer
We should write tests to prevent defects from happening. That is one of the key roles tests play. But not everyone knows there is more to writing tests than that....
Micro Frontends at HolidayCheck (part 2) - Speed
In the first part of this series, I describe why and how we do micro frontends at HolidayCheck. One of the key aspects I described was the focus on speed....
HolidayCheck Camp 2019
Only one strong team that believes in sharing, solution-oriented discussions, has fun together and cares for each other can build the best product. That was the HolidayCheckCamp 2019, Golden Sands...
Micro Frontends at HolidayCheck (part 1)
At HolidayCheck we just released our first Micro Frontend, the “new header”, which is placed above all HolidayCheck pages to guarantee a common look & feel. In this series of...
Resource Timing (part 3) - Waterfall Chart
This is post #3 in the category “Browser Tools”, focusing on understanding the loading times by charting them in a Waterfall chart. In part 1 and part 2 about ResourceTiming...
Tracking manager's work with git
I have been using `git` for quite some time now. In the days were engineering work consumed most of my workday it was my weapon of choice for code versioning....
Resource Timing (part 2) - Loading Dependencies
This is post #2 in the category “Browser Tools”, focusing on understanding Loading Dependencies. In part 1 about ResourceTiming we looked at the attributes responseEnd and startTime. Now we want...
Canary Releases with Traefik on GKE at HolidayCheck
In this post, I would like to introduce you into how Traefik helped us shape our cloud ecosystem at HolidayCheck. In particular, I will give a brief introduction on how...
Read this if you don't like TDD
Recently I saw a video titled "TDD for those who don't need it". It was plain and obvious. But then it struck me, as I realized that there are more...
Resource Timing (part 1) - The API
A look into the Resource Timing API, it is part of the Performance API, which you can reach via 'window.performance' in all modern browsers.
Create Universal Apps Using Next.js
Let’s talk first about libraries for creating universal applications. On GitHub you can find a large number of projects implementing the idea of universal web applications. However, all these projects...
Turning greenfield projects into brownfield projects
Bad code is created in the same way as good code, one line at a time. What makes the difference?
Craft Consultants
As aspiring Software Craftsmen we are raising the bar of professional software development by practicing it and helping others learn the craft.
InnoDays 2018
Ship Some Thing. That was the motto for our InnoDays 2018. We spent 4 days in the Bavarian mountains with an amazing view but limited wifi to work on new...
Simple Slackbot
Recently I’ve built a small slackbot that is posting with certain regularity in a specified Slack channel. I will tell you about the idea behind it and also share some...
#jslang Meetup - Errors
In our offices we have a monthly meetup, which is all about JavaScript language features, we call it “JavaScript The Language” (see twitter #jslang). We pick one language feature and...
Migrating from Galen to Backstop
Visual regression testing has recently started gaining popularity- and for good reason. At its most basic, it’s a series of tests that run through your site, take screenshots of various...
My Apprenticeship
My days as an apprentice are slowly coming to an end. As the final day arrives, I have an irresistible desire to share. I would like to share how I...
Self Organization
I remember the very first day as an apprentice at HolidayCheck. Honestly, it was only four months ago, not so hard to recall. The thing is, it feels like it’s...
The HolidayCheck Apprenticeship
Yesterday marked the public launch of the HolidayCheck Apprenticeship Program. If you want to apply, you can do so right now at https://apprenticeship.holidaycheck.com - But for now, please keep on...
Backlog Priority Automation using Github Apps
Working in small iterations, being data-driven, user-input driven or simply lean is our ideal style of working. And it is awesome when this works. But there are also other situations...
Workflow automation
As engineers, we like to script and automate whatever’s possible. It doesn’t matter if we’re talking about creating three-character-long aliases for a ten-character-long command, adding labels to newly created issues,...
Go: The Beginning
We’ve been already using Go at HolidayCheck for quite some time. There are some services written with Go and also the primary user of it is our infrastructure team. Apart...
Apprenticeship @ HolidayCheck: One month in
On the 16th of January, exactly 1 month ago I was starting my journey as an apprentice at HolidayCheck. At that point, the whole idea of the apprenticeship was this...
Agility Potion +1:
Working with obstacles
Exasperation or disappointment are typical feelings. It does not surprise me anymore how people usually react to unexpected roadblocks. You really wanted to make it happen but now you can’t...
Testing code that isn't there yet
It’s relatively easy to test a piece of code that is already there. Stub dependencies, check calls, returned values. Voilà, there you have it. But what about a code that...
Responsive Images in HTML5: Srcset and Sizes
A long time ago Eric Portis wrote an excellent article about “Srcset and sizes”. With funny pictures. I’ve been told it’s too long though. Let me summarize.
Non-technical summary of JBHC workshop
We were glad to attend J.B. Rainsberger recently, where he presented several working methods from so called micro techniques to more general approaches to improve and enhance everybody’s daily business...
Thoughts on Value Stream Mapping and Theory of Constraints
We had an internal event with J.B. Rainsberger recently, where he presented Value Stream Mapping and Theory of Constraints as a viable approach for improving development team performance.
Haskellaus: Haskell meets Nikolaus
Last Friday we had a very special Haskell meeting at HolidayCheck - we called it Haskellaus. In this post I will explain what it was about and then we look...
Nix in Practice: Providing Dependencies
This is the first of multiple posts about how you can use Nix to solve common problems of developers. We will focus on the solution first, so you can take...
AMP Roadshow in Munich
Google invited lots of developers to the AMP Roadshow that they are currently doing worldwide. We joined the Munich edition in their offices. Google does that to promote their technology...
Haskell Learning Group: Our Progress and Updates
This post is a quick update and the latest news about our Haskell learning group. Even though there were no blog posts on this topic recently, we are still having...
NixCon 2017 In Munich
At HolidayCheck we started using Nix and NixOS roughly 1.5 years ago. After humble beginnings with nothing but a default.nix to provide the correct nodejs version via nix-shell, we are...
Haskell Learning Group: Beyond Maths (2nd Session)
The previous blog post was an introduction to our Haskel Learning Group. This is a new initiative that we started at HolidayCheck recently. As the first chapter was about mathematical...
#jbhc17 from my perspective
When I first heard about JB coming to HolidayCheck to work with us I was excited. I hadn’t heard much about him then, so I began googling him. I did...
Haskell Learning Group - first meeting
In HolidayCheck we believe in the value of learning new things. So the last week we held a first meeting of our Haskell Learning Group. The point of this group...
J.B. Rainsberger in da house
It started in May, when we thought about inviting J.B. Rainsberger to HolidayCheck. Yeah, there was some bias from my side, since I had the pleasure to have learned from...
Apprenticeship at 8th Light
Officially it was 2006 that 8th Light says they had started the apprenticeship program. From reading a bit around and searching for related articles online, it seems that there had...
Learning from 8th Light, Day 1
It all started at BusConf, this August. Tobias Pflug (a colleague from HolidayCheck) asked Daniel Irvine (from 8th Light London) if we could come over to London to learn from...
Property-based testing in JavaScript
As developers we are always looking for new ways to ensure that our code works as we would expected. One way to achieve this, which is not as commonly used...
62 Engineers, 1 All-inclusive hotel
Early in May this year, all HolidayCheck IT engineers, Scrum masters and line managers from all our locations in Poland, Germany and Switzerland had their regular all-developers meetup.
Stretch your mind every morning with coding kata at HC
A code kata is an exercise in programming which helps a programmer hone their skills through practice and repetition
On personal development
I hate beginnings. The feeling of excitement with starting something new is so great that I miss it terribly when it ends. Depending on the attitude it can last long...
Build Custom UI Extensions for Contentful
Contentful is a powerful and developer-friendly CMS solution. In this article I will assume that the reader is already familiar with Contentful itself. Let us also skip the part about...
CoP Testing #2 - Structuring Tests
At HolidayCheck we are doing “Communities of Practice” for various things. The one I started, is the “CoP Testing”, which cares about all things around testing. Since I care a...
EnterJS, ES6, ES8 and Typing with Flow
Back on the road. Three days of EnterJS are just over and I am already on the next trip, this time with HolidayCheck. So let me quickly sum up EnterJS...
Async Function Kata at #jslang Meetup
The callback-hell times are long over. We have better tools now. But which of the new kids on the block do you want to play with? In this meetup, last...
Keeping C.A.L.M.S. at HolidayCheck
In the last article called “Adapting DevOps culture with C.A.L.M.S.” I’ve described the C.A.L.M.S. model and showed its importance and usefulness for proper adaptation of DevOps culture.
Adapting DevOps culture with C.A.L.M.S.
DevOps is still quite a buzzword. There are already plenty of articles describing what it is and what it isn’t. I think we can agree that it’s a culture, a...
