Yorocobu — 目的に合わせた AI エージェント開発と、オーダーメイドのソフトウェア開発

Yorocobu LLC is a software company. What it does is stated plainly: tailored agent engineering, and custom software development.

The company was filed in Wyoming in 2025. Operations are based in Chapel Hill, North Carolina, and the work is done remotely.

The work spans web and mobile, built on React, Swift, and Flutter. Yorocobu takes on client work.

Yorocobu means "to have joy" in Japanese. Helping people find happiness drives everything the company does. That is why it works day and night to make apps that improve quality of life.

The name comes from 喜ぶ, to be glad. The company mark is the kanji 喜, which carries that same sense of gladness, and it sits at the end of the wordmark.

The standard romanization of 喜ぶ is yorokobu, with a k. The company name is spelled yorocobu, with a c.

Yorocobu LLC was founded by two people, who share the title Co-Founder. Both are Morehead-Cain Scholars at the University of North Carolina at Chapel Hill.

What follows is everything the site publishes about them. Anything further is best asked directly.

Yorocobu builds with industry-leading technologies to deliver apps across all platforms.

Primary technologies. React for modern web applications. React Native for cross-platform mobile apps. Swift for native iOS development, and SwiftUI for modern iOS interfaces. Flutter for beautiful native apps.

Also building with. JavaScript, TypeScript, Python, Node.js, Firebase, PostgreSQL, AWS, Git and GitHub, Figma, Docker, REST APIs, and GraphQL.

Yorocobu does two things:

• Tailored agent engineering
• Custom software development

The site does not publish named work, and anyone who wants to talk about a project is welcome to get in touch.

忘れ者 (Wasuremono) is a feature-length documentary about loneliness and connection in Japan, directed and produced by Ethan Gailushas. It runs roughly 90 minutes.

There are two versions. The Japanese version is fully Japanese audio with Japanese subtitles; the English version is in English. Which one to watch is the first thing worth knowing, so the site asks before it hands over a link.

The title

忘れ者 reads as forgotten person. It plays on 忘れ物, the everyday word for a lost or left-behind object — the thing on lost-and-found signs. The film is about people left behind in the same way.

What it covers

Loneliness and connection in contemporary Japan, and the tension between a society organised around convenience and the kinds of connection that convenience makes unnecessary.

Who is in it

• Akihiko Kondo, who married the vocal synthesiser character Hatsune Miku.
• Tokyo's most in-demand rental girlfriend, working as Mary Sakurai.
• Sakura Kudo, a college student in Hokkaido, on friends who maintain a front while wanting connection. Dr. Tsuyoshi Ono, a Tokyo pediatric psychiatrist, is cut into the middle of her interview.
• Tsukimi Ayano, who fills the depopulated village of Nagoro with life-sized dolls of its former residents.
• A children's ice hockey team, the Hiroshima Collectors.

How it was made

Ethan shot, recorded, edited and produced it himself, in Japanese and English, while studying at Keio University on exchange from UNC Chapel Hill. The work was supported by the Morehead-Cain Foundation.

Where to watch

Both versions are on YouTube. The site attaches the links itself, so ask for the film and the choice of language comes with it.

Yorocobu takes on client work in both of the things it builds: tailored agent engineering, and custom software development.

What a project would cost, how long it would take, and whether Yorocobu has room for it right now are all conversations rather than published figures. To start one, describe what you have in mind — Joy can pass it along from here, or you can email ethan@yorocobu.org directly.

There are two ways to reach Yorocobu, and they end up in the same place.

Joy can take the message. Ask her to send something and she will collect it here — a few short questions, a draft you can edit, and nothing leaves until you press send. Leave a reply address and it goes with the message so Ethan can answer you directly; leave it out and the message still arrives, as a note rather than a conversation.

Or write directly. The address is ethan@yorocobu.org, which reaches Ethan. Either route gets to the same place, so use whichever suits you.

Either route is the right one whether you are a prospective client with a project, an investor, or a partner exploring something together.

Yorocobu is also on LinkedIn and Instagram.

Joy is the guide for this site. Ask her anything Yorocobu has published and she will point you to it.

The name is the English of 喜ぶ, to be glad — so the guide and the company are the same word in two languages, and 喜 is the mark the site opens on.

She can do two things. The first is answer from a small set of published entries about Yorocobu and nothing else, which is why she will tell you plainly when something is not in them rather than guessing. The second is take a message: ask her to send a question to Ethan and she will collect it right here, draft it for you to edit, and send it only when you say so. A reply address is optional — with one, Ethan can answer you directly; without one, the question still reaches him.

What she cannot do is answer for Ethan, promise a reply, or tell you what happened to a message after it was sent. She is not a person, and she will say so if you ask.