Yuichi Sato
@yasaichi.com
London-based TypeScript enthusiast functional programming pragmatist. Co-author of a Ruby on Rails book for intermediate-to-advanced developers. Former CTO at a Japanese public company. Blog: https://blog.yasaichi.com/
Pinned
Yuichi Sato
@yasaichi.com
· Nov 26
JSConf JP 2024
Deck https://decks.yasaichi.com/20241123/type-safe-lightweight-ddd-with-effect-schema
Abstract At EARTHBRAIN, we have adopted “Effect,” an emerging TypeScript library, to develop an API gateway. This ...
blog.yasaichi.com
Blogged the recent presentation at JSConf JP. blog.yasaichi.com/post/jsconf-...
Reposted by Yuichi Sato
NEWS: The UK is no longer sharing intelligence with the US about suspected drug trafficking vessels in the Caribbean because it does not want to be complicit in US military strikes and believes the attacks are illegal, sources familiar with the matter told CNN. edition.cnn.com/2025/11/11/p...
Exclusive: UK suspends some intelligence sharing with US over boat strike concerns in major break | CNN Politics
The United Kingdom is no longer sharing intelligence with the US about suspected drug trafficking vessels in the Caribbean because it does not want to be complicit in US military strikes and believes ...
edition.cnn.com
November 11, 2025 at 3:06 PM
NEWS: The UK is no longer sharing intelligence with the US about suspected drug trafficking vessels in the Caribbean because it does not want to be complicit in US military strikes and believes the attacks are illegal, sources familiar with the matter told CNN. edition.cnn.com/2025/11/11/p...
Blogged a new article for the first time in six months: blog.yasaichi.com/when-you-see...
When You See Abstract Structures, Design Becomes Easier
While developing an e-commerce system, I once designed a model called DeliveryDateConstraint to represent delivery restrictions decided by sellers. At first, it looked simple enough: each product had its own shipping rule.But later I realised that cu...
blog.yasaichi.com
November 8, 2025 at 5:15 PM
Blogged a new article for the first time in six months: blog.yasaichi.com/when-you-see...
Recently, many SaaS companies have been trying to transform their applications into AI-powered products in order to stay competitive and boost revenue growth. However, this strategy may eventually fail as they are unable to utilize LLMs at their cost price. www.morningstar.com/news/marketw...
AI is eating software, and Adobe is on the menu. Why the stock could be in trouble.
www.morningstar.com
November 8, 2025 at 9:37 AM
Recently, many SaaS companies have been trying to transform their applications into AI-powered products in order to stay competitive and boost revenue growth. However, this strategy may eventually fail as they are unable to utilize LLMs at their cost price. www.morningstar.com/news/marketw...
“AI’s ability to write code in a language is proportional to how much of that language it’s seen. It’s a big regurgitator, with some extrapolation. AI has seen tons of JavaScript, Python, and TypeScript so it’s great at writing them.” github.blog/developer-sk...
TypeScript’s rise in the AI era: Insights from Lead Architect, Anders Hejlsberg
TypeScript just became the most-used language on GitHub. Here’s why, according to its creator.
github.blog
November 6, 2025 at 6:07 PM
“AI’s ability to write code in a language is proportional to how much of that language it’s seen. It’s a big regurgitator, with some extrapolation. AI has seen tons of JavaScript, Python, and TypeScript so it’s great at writing them.” github.blog/developer-sk...
context7 and inspector seem valuable to give a try for me. github.blog/open-source/...
Accelerate developer productivity with these 9 open source AI and MCP projects
These nine open source MCP projects provide new frameworks, tools, and assistants to unlock AI-native workflows, agentic tooling, and innovation.
github.blog
November 5, 2025 at 12:27 PM
context7 and inspector seem valuable to give a try for me. github.blog/open-source/...
My recent activities as amateur photographer: unsplash.com/@yasaichi
Yuichi (@yasaichi) | Unsplash Photo Community
See 16 of the best free to download photos, images, and wallpapers by Yuichi on Unsplash.
unsplash.com
November 5, 2025 at 7:57 AM
My recent activities as amateur photographer: unsplash.com/@yasaichi
Now watching the series of Category Theory for Programmers: youtu.be/SmXB2K_5lcA?...
Category Theory for Programmers: Chapter 1 - Category
YouTube video by code_report
youtu.be
October 30, 2025 at 6:49 PM
Now watching the series of Category Theory for Programmers: youtu.be/SmXB2K_5lcA?...
Even though it is not a full genetic scan, the 23andMe results, combined with blood tests from another provider, provide me with a lot of beneficial information. It is one of the best investments in recent years.
October 27, 2025 at 6:59 PM
Even though it is not a full genetic scan, the 23andMe results, combined with blood tests from another provider, provide me with a lot of beneficial information. It is one of the best investments in recent years.
I’ve sold almost all my assets to reduce my heavy exposure to major US companies, and started buying various assets in multiple currencies other than the US dollar.
October 26, 2025 at 1:14 PM
I’ve sold almost all my assets to reduce my heavy exposure to major US companies, and started buying various assets in multiple currencies other than the US dollar.
Google Testing Blog mentioned one of my favorite principles: Functional Core, Imperative Shell testing.googleblog.com/2025/10/simp...
Simplify Your Code: Functional Core, Imperative Shell
This article was adapted from a Google Tech on the Toilet (TotT) episode. You can download a printer-friendly version of this TotT epis...
testing.googleblog.com
October 25, 2025 at 7:33 AM
Google Testing Blog mentioned one of my favorite principles: Functional Core, Imperative Shell testing.googleblog.com/2025/10/simp...
Maya is the best ever www.youtube.com/watch?v=8cEd...
XG - GALA (Official Music Video)
YouTube video by XG
www.youtube.com
September 22, 2025 at 7:21 PM
Maya is the best ever www.youtube.com/watch?v=8cEd...
How good HYBE at illustrating the nostalgia everyone has in their minds www.youtube.com/watch?v=Heqs...
ILLIT (아일릿) '時よ止まれ (Toki Yo Tomare)' Official MV
YouTube video by HYBE LABELS
www.youtube.com
September 13, 2025 at 6:33 PM
How good HYBE at illustrating the nostalgia everyone has in their minds www.youtube.com/watch?v=Heqs...
Read it later: dcb.events
Dynamic Consistency Boundary - Dynamic Consistency Boundary
DCB – A simpler and more flexible approach to consistency in event-driven systems
dcb.events
September 13, 2025 at 8:57 AM
Read it later: dcb.events
About to leave Claude Code after seeing the leaderboard of github.com/laiso/ts-bench. The first step is to use Opus model via this taking advantage of the existing Pro Plan I am subscribing.
GitHub - laiso/ts-bench: Measure and compare the performance of AI coding agents on TypeScript tasks.
Measure and compare the performance of AI coding agents on TypeScript tasks. - laiso/ts-bench
github.com
September 8, 2025 at 12:41 PM
About to leave Claude Code after seeing the leaderboard of github.com/laiso/ts-bench. The first step is to use Opus model via this taking advantage of the existing Pro Plan I am subscribing.
The second edition is coming! 🎉
🤩 My author copies of Team Topologies Second Edition have arrived ... and they look amazing! The new case studies and commentaries bring the ideas to life.
Join us on 25 September online for the launch event: teamtopologies.com/launch - pay as you feel 🎫
Join us on 25 September online for the launch event: teamtopologies.com/launch - pay as you feel 🎫
August 25, 2025 at 2:30 PM
The second edition is coming! 🎉
Reminds me of the vibe of remix movies to reproduce music videos for Perfume songs such as Perfect Star Perfect Style using materials from the Idolmaster game in Japan around 2009. youtu.be/L1mFVp9IM9c
AiScReam『愛♡スクリ～ム！』Official Lyric Video
YouTube video by (Love Live! series)ラブライブ！シリーズ公式チャンネル
youtu.be
August 24, 2025 at 8:42 AM
Reminds me of the vibe of remix movies to reproduce music videos for Perfume songs such as Perfect Star Perfect Style using materials from the Idolmaster game in Japan around 2009. youtu.be/L1mFVp9IM9c
There were no Ruby books sadly, but it's reality Rubyists have to see.
August 23, 2025 at 9:03 PM
There were no Ruby books sadly, but it's reality Rubyists have to see.
According to the official announcement, the recent released Notion offline mode is based on Peritext (github.com/inkandswitch...), CRDT for asynchronous rich-text collaboration.
GitHub - inkandswitch/peritext: A CRDT for asynchronous rich-text collaboration, where authors can work independently and then merge their changes.
A CRDT for asynchronous rich-text collaboration, where authors can work independently and then merge their changes. - inkandswitch/peritext
github.com
August 20, 2025 at 5:50 PM
According to the official announcement, the recent released Notion offline mode is based on Peritext (github.com/inkandswitch...), CRDT for asynchronous rich-text collaboration.
how emotional this is www.youtube.com/watch?v=1xUf...
【#ちはやふる－めぐり－】Perfume「巡ループ」ドラマコラボPV【主題歌】
YouTube video by 日テレドラマ公式チャンネル
www.youtube.com
August 6, 2025 at 8:07 PM
how emotional this is www.youtube.com/watch?v=1xUf...
I believe “Event Is All You Need” in solving various types of issues in software because this would be the single source of truth for what happened in your system. In addition, codebase built on effect system empowers LLMs to trace the event -> db -> state -> UI -> event loop.
LLMs need data with context to fuel the best possible outputs. Event-native data provides the "why," “how” & "when" behind every business action.
When your data speaks the same language as your #AI, that’s when the magic happens. ✨
Learn more: www.kurrent.io/use-cases/ai...
When your data speaks the same language as your #AI, that’s when the magic happens. ✨
Learn more: www.kurrent.io/use-cases/ai...
August 5, 2025 at 8:46 PM
I believe “Event Is All You Need” in solving various types of issues in software because this would be the single source of truth for what happened in your system. In addition, codebase built on effect system empowers LLMs to trace the event -> db -> state -> UI -> event loop.
Facing the same issue in v1.0.64. github.com/anthropics/c...
github.com
July 31, 2025 at 3:11 PM
Facing the same issue in v1.0.64. github.com/anthropics/c...
Another “result” library in TypeScript, probably inspired by Effect, looks more practical than neverthrow in some areas: it provides generator functions with `this` context, pattern matching for errors, etc. www.typescript-result.dev
TypeScript Result
Supercharge your TypeScript error handling with a powerful Result type that transforms chaotic try-catch blocks into elegant, type-safe code.
www.typescript-result.dev
July 30, 2025 at 7:46 AM
Another “result” library in TypeScript, probably inspired by Effect, looks more practical than neverthrow in some areas: it provides generator functions with `this` context, pattern matching for errors, etc. www.typescript-result.dev
In traditional CRUD systems, Update/Delete ops only preserve the final state via state = query(db), losing the original event history. The upcoming challenge: how we retroactively discover and materialize these lost events while aligning with existing table-coupled legacy code. x.com/DavidKPiano/...
David K 🎹 on X: "Events are the most accurate representation of state. Everything else is a lossy abstraction. LiveStore gets it right ⚡️ https://t.co/8DYNbA9AVO" / X
Events are the most accurate representation of state. Everything else is a lossy abstraction. LiveStore gets it right ⚡️ https://t.co/8DYNbA9AVO
x.com
July 27, 2025 at 10:44 AM
In traditional CRUD systems, Update/Delete ops only preserve the final state via state = query(db), losing the original event history. The upcoming challenge: how we retroactively discover and materialize these lost events while aligning with existing table-coupled legacy code. x.com/DavidKPiano/...
The Phantom of Baker Street
July 26, 2025 at 9:22 PM
The Phantom of Baker Street