Markus Harrer
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markusharrer.de
Markus Harrer
@markusharrer.de
300 followers 260 following 110 posts
Software Development Analyst @innoq, Trainer @socreatory. I like fixing things. Legacy systems, Wardley Maps, DDD and Software Analytics fanboy. https://markusharrer.de/
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markusharrer.de
September 23, 2025 at 9:05 AM
markusharrer.de
August 29, 2025 at 7:10 AM
markusharrer.de
August 11, 2025 at 5:20 PM
markusharrer.de
I've collected and structured some software modernization strategies in an overview: feststelltaste.github.io/littlestmode...
July 30, 2025 at 6:15 PM
markusharrer.de
"To AI or not to AI", that is the question.

This is why I've created a one-page guide that helps you make decisions on when and how to use AI for software modernization.

PDF: speakerdeck.com/feststelltas...

#legacy #ai #modernization
June 23, 2025 at 7:59 AM
markusharrer.de
May 21, 2025 at 8:02 AM
markusharrer.de
I'm working on a new hands-on version of my software architecture improvement training (iSAQB IMPROVE) using good old Fischertechnik (hey, it's about a legacy system, okay?). Here you can see a feature toggle in action. 😬
April 8, 2025 at 7:13 AM
markusharrer.de
To find your inner peace using vibe coding as a programmer, you absolutely have to make sure you put that in the very first line of your generated scripts 😄: # vibe coded
The first lines of a Python script where the first line is "# vibe coded"
April 7, 2025 at 11:05 AM
markusharrer.de
Developers before the MCP hype: Ugh, not another API from someone else I have to deal with... Developers during the MCP hype: Awesome! Another API from others I get to deal with!
March 26, 2025 at 11:30 AM
markusharrer.de
Just a quick demo, nothing fancy: Importing CodeCharta files into Pandas, visualizing / adding some stuff and export it again to visualize also the new stuff in CodeCharta Web Studio:

nbviewer.org/github/fests...
March 22, 2025 at 9:21 AM
markusharrer.de
How is your morning going? My source code analysis tool just crashed because of too many source code files 🤪 #softwarearchaeology
March 21, 2025 at 7:18 AM
markusharrer.de
Meet me at @amaconf.bsky.social April 3 - 4, 2025 in Berlin. I'll be speaking about how Wardley Mapping can help software architects avoid both overengineering and underengineering software quality. I'm also talking about why building in quality into software systems becomes harder over time.
Quality is all about the How, not the What.
March 14, 2025 at 11:49 AM
markusharrer.de
Back then, I hadn’t thought something like this would ever happen - until today: Claude Code also knows my work on data-driven software analysis of software systems and can now write similar scripts to gain a deeper understanding of software systems and their evolution.

This is really 🤯
March 13, 2025 at 10:29 AM
markusharrer.de
Great that Claude Code knows all my Software Analytics Jupyter Notebooks on GitHub. That's very handy now 🤣
March 13, 2025 at 10:06 AM
markusharrer.de
Me: The handle on the toaster is broken. I need a 3D printer for printing out a replacement part!
My wife:
The toaster handle fixed by a clip from IKEA for closing plastic bags.
December 3, 2024 at 11:15 AM
markusharrer.de
These are my most-starred GitHub repositories. Not so bad for such niche topics, I guess. 😊

Links and more here: star-history.com#feststelltas...
December 3, 2024 at 10:31 AM
markusharrer.de
I don't understand why someone should use anything like the C4 model. The agile manifesto clearly states that you should not use tools, plans and documentation at all!!11!1eleven!1!11! /s
December 3, 2024 at 9:49 AM
markusharrer.de
Hello new followers! Welcome! I'm primarily writing about all the things that could make the lives of developers working on legacy systems more enjoyable 😊. (And thanks for the nostalgic Twitter vibes from earlier times! 😃)
An image from the movie Avengers: Endgame showing Captain America leading a group of heroes into battle, with the text 'FORMER TECH TWITTERERS ASSEMBLE'.
November 27, 2024 at 8:12 PM
markusharrer.de
meetup.com is next
November 22, 2024 at 7:00 PM
markusharrer.de
Naming things is one of the hardest problems in software development 🤯. Beyond creativity challenges, synonymy (many names for one thing) and polysemy (one name, many meanings) can easily confuse developers 😖. The fix? Ensure integrity with consistent, clear concepts throughout your codebase. 💡
The image contrasts natural language issues with best practices in code. On the left, it shows problems in natural language: synonymy (one thing, many names like DataAccess, Repository, EntityHandler) and polysemy/homonymy (one name, many things like Client, Order, Entity). On the right, it illustrates the solution in code: integrity through consistent naming, where one thing maps to one clear concept, such as Customer, procurement.Order, and data.*Entity. The image emphasizes the importance of conceptual integrity in software architecture to prevent confusion.
November 18, 2024 at 9:16 AM
markusharrer.de
Yes, but that's what the documentation said!
November 15, 2024 at 9:51 AM
markusharrer.de
Fixed this slide 😅 (und danke für den Einblick hinter die text2cypher Kulissen)
November 6, 2024 at 2:35 PM
markusharrer.de
I've created a new Twitter banner. Feel free to use and change as you like: gist.githubusercontent.com/feststelltas...
November 6, 2024 at 7:15 AM
markusharrer.de
Am I'm doing this right?
November 5, 2024 at 10:12 PM
markusharrer.de
I think a new era of Software Analytics is emerging, where we can not only analyze software systems in a context-specific way to find appropriate solutions but also improve software systems through data-driven approaches,too. Interesting times 😊
November 5, 2024 at 9:41 PM