Small, useful apps for families — built on the Claude API.
Milky Way Day is a sole-proprietor studio run by Ayaka Tokino. We make the tools we wanted for our own family of four, then release them: a school-handout reader powered by Claude vision, a kanji-learning app on the App Store, and the media business that funds them.
See the productsProducts
What we are building and shipping today.
Otayori Calendar — school handouts to calendar, in one photo
Japanese schools send home paper handouts (otayori) every week: events, deadlines, things to bring. Parents retype them by hand. Otayori Calendar takes a photo of the handout and returns a structured list of events, deadlines and items, ready to add to the family calendar. It runs on Claude's vision and structured output, with date validation tuned for Japanese school documents (fiscal-year dates, weekday cross-checks, era-year conversion).
Output from Claude · actual result
To-do with deadlines
Notices
Status: in daily use by the founder's family since spring 2026; public release in preparation. Stack: Next.js on Cloudflare Workers, Claude Messages API (vision + JSON schema output).
iOS · App Store · released 2026-09-12
Kanji Aquarium with Pea-chan
ぴーちゃんと かんじのすいぞくかん
A kanji-writing app for elementary-school children: write a character stroke by stroke, and sea creatures join your aquarium. Covers all 1,026 kyōiku kanji with stroke-order checking and a kid-friendly dictionary. Made by a mother for her daughter, then published.
Tools that run our media business
- Subtitle & metadata localization pipeline — translates our travel-vlog subtitles, titles and descriptions into 15 languages with Claude Opus, with cue-count and timing validation. Runs on every episode.
- Family assistant on LINE — scheduling, reminders and meal logging for the family, with Claude parsing free-text requests. Cloudflare Workers + KV.
- Travel log — records time, place and weather on the road (Cloudflare D1) and feeds blog posts and video subtitles.
These are private, but they are where most of our Claude API usage happens today.
Media business
The audience and revenue that fund product work.
YouTube
- Noir Archive — vintage noir jazz, 2,600+ subscribers, 24/7 live stream and channel memberships.
- nest on wheels — a Japanese family's campervan travel vlog, subtitled in 15 languages with our Claude pipeline.
Blogs
- rvlife-family.com — family campervan travel in Japan (200+ nights on the road).
- くらしの見直し部 — comparisons of family subscriptions and services.
About
Who we are.
- Business name
- Milky Way Day（屋号）— registered sole proprietorship, Japan
- Founder
- Ayaka Tokino
- Founded
- April 2024 — registered as a sole proprietorship (Milky Way Day), originally selling handmade accessories. Media business launched April 2025; first software product shipped September 2026.
- Location
- Yao, Osaka, Japan
- Team
- 1 founder. Engineering, design and content are done with Claude Code as the daily workbench.
- Funding
- Bootstrapped. No outside funding.
- Stack
- Claude API (Opus 5.5)Claude CodeNext.jsCloudflare Workers / D1 / KV / AccessCapacitor (iOS)
- Contact
- hello@milkywayday.app
日本語
Milky Way Day（屋号）について
Milky Way Day は、大阪府八尾市で時野綾香（Ayaka Tokino）が1人で運営する個人事業です（2024年4月にハンドメイドアクセサリーの事業として開業届を提出。2025年からメディア事業、2026年からアプリ開発）。4人家族の自分たちが欲しかった道具を、Claude API を使って作り、公開しています。
- おたよりカレンダー（公開準備中）— 学校のプリントを写真に撮ると、行事・締切・持ち物を読み取ってカレンダーに入れられる形にします。Claude Opus 5.5 の画像認識と構造化出力を使用。家族で2026年春から毎日使っています。
- ぴーちゃんと かんじのすいぞくかん（iOS・App Store・2026年9月12日公開）— 漢字を書くと海の仲間が増える、小学生向けの漢字学習アプリ。教育漢字1,026字・書き順判定・子ども向け辞典つき。
- 社内ツール — 旅Vlogの字幕・説明文を15言語に訳すパイプライン、家族用LINE秘書、旅ログ。いずれも Claude API で動いています。
メディア事業（YouTube「Noir Archive」「nest on wheels」、ブログ「rvlife-family.com」「くらしの見直し部」）が製品づくりの資金源です。
お問い合わせ：hello@milkywayday.app