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Szymon Fiedler

@szymonfiedler.bsky.social
86 followers 181 following 47 posts

I build software I’m willing to maintain for years. Payments, insurance, DDD. RailsEventStore maintainer. Arkency. wroclove.rb co-organizer.

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Szymon Fiedler @szymonfiedler.bsky.social · 25/06/2026
Hopefully, we've got you covered blog.arkency.com/tags/time/
0 days without timezone issues in a rails project
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Szymon Fiedler @szymonfiedler.bsky.social · 24/06/2026
Likewise. Polymorphic queries should be a good one, looking forward to it!
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Szymon Fiedler @szymonfiedler.bsky.social · 24/06/2026
Thanks Brandon, appreciate it. Saw the new one’s already up — on my list.
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Szymon Fiedler @szymonfiedler.bsky.social · 18/06/2026
I strongly agree with Weaver's "Callbacks Are Not Invariants": callbacks can't keep their promise, writes go through one door. The ingress doesn't own the invariant. The aggregate does. And the persisted fact, not the outbox, makes effects recoverable. blog.arkency.com/ingress-is-n...
blog.arkency.com
Ingress is not the owner of the invariant
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Szymon Fiedler @szymonfiedler.bsky.social · 24/04/2026
We would have to move @wrocloverb.com to the turn of September and October 😉
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Szymon Fiedler @szymonfiedler.bsky.social · 24/04/2026
As a Polish person I endorse this comparison to our national sport 🍄‍🟫🍄‍🟫🍄‍🟫 „I tend to treat performance gains like mushroom hunting. When you find a mushroom, it usually means that it’s an area where they grow well, and that no other mushroom hunter has passed by recently.”
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Szymon Fiedler @szymonfiedler.bsky.social · 23/04/2026
Patrick Bateman meme saying „Impressive, 
very nice. Now, let’s put usable OS on that”
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wroclove.rb @wrocloverb.com · 22/04/2026
That’s a wrap on wroclove.rb 2026! What we’ll remember most are the smiles, great discussions, and afterparty vibes. That energy keeps us going – sending a heartfelt thank you to everyone who joined us 🫶 May this postcard bring you all warm memories of wroclove.rb 2026!
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Szymon Fiedler @szymonfiedler.bsky.social · 19/04/2026
I knew nothing and learned everything, thanks!
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Szymon Fiedler @szymonfiedler.bsky.social · 19/04/2026
@mackuba.eu on his work with AT protocol in Ruby @wrocloverb.com
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wroclove.rb @wrocloverb.com · 08/04/2026
This is Wrocław in 1825. Curious how it looks today and how it changed along the way? Join our free guided walking tour on Sunday at 15:00, right after the conference and enjoy Wrocław's charm! Sign up for the tour here ➡️ buytickets.at/wrocloverb/1... Source: fotopolska.eu
Panorama Ostrowa Tumskiego, źródło: fotopolska.eu
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Szymon Fiedler @szymonfiedler.bsky.social · 23/02/2026
Will do!
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Szymon Fiedler @szymonfiedler.bsky.social · 23/02/2026
So happy to be speaking along with @cplanas.bsky.social, @yatishmehta.com and other Ruby folks!
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Szymon Fiedler @szymonfiedler.bsky.social · 08/02/2026
When he asked who uses unicorn, only few people from over 500 raised their hands (including me at that time)😅
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Szymon Fiedler @szymonfiedler.bsky.social · 06/02/2026
New post: A timezone bug that hid for months — using Time.now to get DST offset for historical dates. Simple fix, but a good reminder to test with explicit timezone manipulation. blog.arkency.com/the-timezone...
Screenshot showing two snippets of code illustrating improperly working code
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wroclove.rb @wrocloverb.com · 02/02/2026
Tickets are now on sale! 🎟️ Amazing speakers, hands-on workshops, and great vibes ahead. Grab your ticket now! wrocloverb2026.konfeo.com/en/groups P.S. We’ve wrapped up CFP reviews and will announce the full agenda soon - stay tuned 🔥
Tickets on sale
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Szymon Fiedler @szymonfiedler.bsky.social · 26/01/2026
Speaking at @rbqconf.bsky.social in Austin (March 26-27) about mutation testing for validating AI-generated tests. Topic emerged after months of experimenting with AI in legacy code at Arkency. Let's see if Mutant can catch bugs in LLM-written tests 😎 rbqconf.com#:~:text=Szym...
rbqconf.com
RBQ Conf
RBQ Conf is a regional Ruby gathering where code meets community, with meaty talks, saucy insights, and plenty of time to connect. Coming to Austin, TX on March 26 & 27, 2026.
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wroclove.rb @wrocloverb.com · 15/12/2025
CFP closes in 30 days! ⏳ If you’ve been thinking about submitting a talk, now’s the perfect time. We’d love to hear your ideas! And if there’s someone you’d love to see on the #wrocloverb stage - share this with them and give them a nudge 👀
image
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wroclove.rb @wrocloverb.com · 09/12/2025
The second batch of tickets is almost gone - we can't wait to see you all at #wrocloverb! 🤩 If you'd like to join us as a speaker, our CFP is still open and we're waiting to hear your ideas! Inspire your fellow developers, submit your talk here ➡️
papercall.io
PaperCall.io - wroclove.rb 2026
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wroclove.rb @wrocloverb.com · 06/12/2025
Santa is very generous to us today - he’s bringing two great announcements: 📣 Let’s welcome our first speaker - @ismaelcelis.com will join us to explore Event Sourcing and the Actor model in Ruby! 🎟️ The second batch of tickets goes on sale on Monday, Dec 8 at 10:00 CET - don't miss it!
Ismael Celis
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Szymon Fiedler @szymonfiedler.bsky.social · 02/11/2025
Congrats!
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Szymon Fiedler @szymonfiedler.bsky.social · 31/10/2025
That feeling when a single-purpose class eliminates 100+ instances of `message << " | "`. Ruby 3.4 forced my hand, but I'm not complaining. blog.arkency.com/the-joy-of-a...
blog.arkency.com
The Joy of a Single-Purpose Class: From String Mutation to Message Composition
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Szymon Fiedler @szymonfiedler.bsky.social · 29/10/2025
Nothing fancy on my side theme = dark:Rose pine moon,light:Rose pine dawn window-height = 40 window-width = 120 font-family = "JetBrainsMono Nerd Font Mono" font-size = 14 font-thicken = false adjust-cursor-thickness = 200% copy-on-select = clipboard
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Szymon Fiedler @szymonfiedler.bsky.social · 29/10/2025
Nope, but I’ll probably submit it to upcoming conferences as it was well received so far. It starts as a rant on Rubocop rules, but then there’s this nice plot twist with over 26k db records broken and some other 6k as a sideffect.
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Szymon Fiedler @szymonfiedler.bsky.social · 29/10/2025
Btw. @joel.drapper.me it had perfect timing with your post „Bugs of Omission and Bugs of Commission”, so I mentioned it on my slides. The bug itself was obviously the latter.
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Szymon Fiedler @szymonfiedler.bsky.social · 29/10/2025
For the sake of formatting, I prefer tools like github.com/ruby-syntax-... (it integrates with Rubocop, btw.) But still, I also align with team practices. But at some point in time I question those who don't make much sense or cause harm. Maybe I should submit my talk to some upcoming conferences😅
github.com
GitHub - ruby-syntax-tree/syntax_tree: Interact with the Ruby syntax tree
Interact with the Ruby syntax tree. Contribute to ruby-syntax-tree/syntax_tree development by creating an account on GitHub.
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Szymon Fiedler @szymonfiedler.bsky.social · 29/10/2025
Thanks for your input Lucian! Speaking of `===`, please see my response below. All your points are valid, I'm not against Rubocop. My problem is that people push too much on `Style/*` rules, while there many much more important and more useful, like `Security/*`, `Lint/*` ones. Or custom ones.
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Szymon Fiedler @szymonfiedler.bsky.social · 29/10/2025
That's a neat trick! `===` is semantically meningful for Range, Regexp, Class, Proc... I don't get banning it and forcing awkward workarounds that are often less clear about intent. Recently, I had a talk on Poznań Ruby User Group about data damage caused by enforcing this Rubocop Rule ;)
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Jean Boussier @byroot.bsky.social · 28/10/2025
I was recently reminded that not everyone fully understand what the frozen string literal magic comment is about. So I figured it was the occasion for another deep dive. byroot.github.io/ruby/perform...
byroot.github.io
Frozen String Literals: Past, Present, Future?
If you are a Rubyist, you’ve likely been writing # frozen_string_literal: true at the top of most of your Ruby source code files, or at the very least, that you’ve seen it in some other projects.
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Szymon Fiedler @szymonfiedler.bsky.social · 28/10/2025
Serious question: What were the drivers behind enforcing Rubocop’s Style/CaseEquality rule (prohibiting ===) in your codebase? „rubystyle.guide said so” is not the answer that makes me satisfied.
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Szymon Fiedler @szymonfiedler.bsky.social · 22/10/2025
I’m more of a filter coffee person. I don’t have espresso machine, but I’ve experimented with aeropress filter on the top of coffee in moka pot back in the days. I like espresso very much, but I don’t drink enough of it to buy a machine and moka pot is too much hassle to get desired quality of shot.
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Szymon Fiedler @szymonfiedler.bsky.social · 22/10/2025
Don’t you lose crema because of that?
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Joel Drapper 🇬🇧❤️🇺🇦 @joel.drapper.me · 21/10/2025
I wrote about the designing the perfect type signature syntax in Ruby.
joel.drapper.me
The journey to the perfect type signature in Ruby
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Jan Dudulski @jan.dudulski.pl · 15/10/2025
Why do we do this ourselves? We are feeding the rich with our knowledge without any benefits in return. Instead, they make content hard to read, hard to search, hard to edit, and hard to follow. And hire algorithms to throw trash into our feeds. More: dudulski.pl/2025/10/15/f...
dudulski.pl
~/We broke the internet. We can still fix it
Jan Dudulski personal site
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Szymon Fiedler @szymonfiedler.bsky.social · 15/10/2025
Is this 404 kind of trolling?
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Szymon Fiedler @szymonfiedler.bsky.social · 15/10/2025
Great points! Btw. there’s a book titled „Slack: Getting Past Burnout, Busywork, and the Myth of Total Efficiency” by Tom DeMarco on that topic
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Szymon Fiedler @szymonfiedler.bsky.social · 14/10/2025
Absolutely love it! I use @neovim.io, btw. 🤣
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wroclove.rb @wrocloverb.com · 13/10/2025
CFP for #wrocloverb 2026 is already open! ⏲️ We aim for ~30 min talk 🗣️ First-time speakers are more than welcome! 🗓️ We are waiting for your submissions until January 13th
papercall.io
PaperCall.io - wroclove.rb 2026
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wroclove.rb @wrocloverb.com · 26/09/2025
Save the date! @wrocloverb.com is back on April 17–19, 2026 💎 We’ve got big plans to make this edition unforgettable. Stay tuned for updates - and see you in Wrocław!
image
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Szymon Fiedler @szymonfiedler.bsky.social · 23/09/2025
media.tenor.com
a man is standing in a room with his hands in his pockets and looking at the camera .
ALT: a man is standing in a room with his hands in his pockets and looking at the camera .
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Kent Beck @kentbeck.com · 28/05/2025
Periodic reminder: before you start organizing stuff, throw away anything unused first. Works for code, clothes, tools, art supplies.
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Szymon Fiedler @szymonfiedler.bsky.social · 06/05/2025
See you there 😉
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Szymon Fiedler @szymonfiedler.bsky.social · 01/05/2025
You may find this fresh talk by @wojtodzio.bsky.social interesting: youtu.be/6DS0WaosX10
youtu.be
12. Wojtek Wrona - From PostgreSQL to SQLite in Rails - wroc_love.rb 2025
YouTube video by wrocloverb
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Szymon Fiedler @szymonfiedler.bsky.social · 18/04/2025
I knew you’ll like it 🤣
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Szymon Fiedler @szymonfiedler.bsky.social · 17/04/2025
Probably verbs are the biggest struggle with their forms: I went - Ja poszedłem (M), Ja poszłam (F) You went - Ty poszedłeś (M), Ty poszłaś (F) She went - Ona poszła He went - On poszedł It went - Ono poszło We went - My poszliśmy (M/F) They went - Oni poszli (M), One poszły (F), Oni poszli (M+F)
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Szymon Fiedler @szymonfiedler.bsky.social · 17/04/2025
We have jej/jego in Polish 😉
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Szymon Fiedler @szymonfiedler.bsky.social · 12/04/2025
Today is the day @wrocloverb.com #wrocloverb #wrocloverb2025
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Łukasz Reszke @lukaszreszke.bsky.social · 09/04/2025
- Turbo Drive - Turbo Frames - Turbo Streams (including broadcasting) - aaaand Stimulus Doesn't ring a bell? Don't worry. You can still come. We'll serve it on plate. The price? You just need conference ticket. That's all. So, see you there?
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Łukasz Reszke @lukaszreszke.bsky.social · 09/04/2025
You can still join the From Static to Reactive: Hotwire Basics for Rails Devs workshop that @maciejkorsan.bsky.social and I will be hosting at @wrocloverb.com If you trust us with 180 minutes of your time you'll discover flavours of Hotwire such as: 1/2
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Szymon Fiedler @szymonfiedler.bsky.social · 31/03/2025
I should order one of those
Fuck daylight savings time t-shirt
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