Daily issue / 2026-09-28
Useful things that surfaced in Hacker News discussions on 2026-09-28. Open the context to see why each one caught our attention—or jump straight to the original thread.
What we found
A formal-modeling language for testing system designs before implementation; one user found transaction bugs.
Source discussion: The internet discovers TLA+. Now what?
“A lot of transaction and atomic bugs were found and fixed just by having such simple instruction alone.”
stevefan1999 · recommendation · first hand use
Direct HN comment
A local AWS emulator for integration tests; a commenter praised its SES support.
Source discussion: Fakecloud: Local AWS cloud emulator for integration tests
“The support for SES looks really great, better than LocalStack.”
zeronone · recommendation
Direct HN comment
A paid search engine; a longtime user likes its results and customer-first model.
Source discussion: When did Google get so weird?
“I've been using Kagi for a couple years now and haven't looked back.”
kelnos · recommendation · first hand use
Direct HN comment
“Searching first is how Kagi assistant works and it's great.”
terribleperson · recommendation
Direct HN comment
A macOS app for using websites as desktop wallpapers; tested with Lofi Cities.
Source discussion: Show HN: Lofi Cities – Pixel-art city nights with browser-generated lofi
“Just tested and this works great on macOS with Plash [1] by Sindre Sorhus.”
andelink · recommendation · evaluated
Direct HN comment
A paid macOS live-wallpaper app; a user reports good results with it.
Source discussion: Show HN: Lofi Cities – Pixel-art city nights with browser-generated lofi
“While it's not free or a first party offering, I've had great success with Cindori Backdrop:”
Vakaiser · recommendation · first hand use
Direct HN comment
Browser-based pixel-city scenes with procedurally synthesized lofi music; commenters praised the presentation.
Source discussion: Show HN: Lofi Cities – Pixel-art city nights with browser-generated lofi
“Gorgeous, very well executed.”
timenotwasted · recommendation
Direct HN comment
“I love the FM synth in the music.”
bitwize · recommendation
Direct HN comment
A site for watching AI agents battle; a commenter liked the experience and aesthetic.
Source discussion: Show HN: TinyAIArena watch AI agents battle it out
“I love this and the aesthetic.”
rao-v · recommendation
Direct HN comment
Agner Fog's freely available C++ optimization PDF; a commenter flagged it as promising.
Source discussion: Writing Efficient C++ Code (2013)
“I've not read Fog's Optimizing software in C++ but I see it's freely available there as a PDF (182 pages). Looks like a great resource on these topics.”
MaxBarraclough · recommendation
Direct HN comment
A TLA+ video course taught by Leslie Lamport; recommended as an approachable introduction.
Source discussion: The internet discovers TLA+. Now what?
“This is a lovely little course on TLA+ by Lamport himself - has some great wigs too”
drpacman · recommendation
Direct HN comment
James Somers' essay about choosing dictionaries; one reader says it changed their life.
Source discussion: When did Google get so weird?
“James Somers’ You’re probably using the wrong dictionary (2014) changed my life for the better.”
willturman · recommendation
Direct HN comment