Kakari-san | Sign-up Sheet for Assignments, Duties, and Potluck Contributions

PTA and children's association role assignments, flag-waving duty rosters, potluck sign-ups, individual consultation time slots.

I created this to eliminate the sight of LINE messages saying "Could someone please help? 🙏" where only read receipts keep piling up.

What it can do

• No registration required for organizers or participants
• Just open the URL and write your name in an available slot
• Slots automatically become "Full" and close when capacity is reached
• Compatible with LINE sharing, QR codes, A4 printing, and CSV export

Why I created it

In Japan, tools like "Chouseisan" and "Walica" have achieved near-perfect penetration as registration-free URL-sharing services. However, there was one critical gap: named sign-up sheets with "slots × capacity × names"—tools like SignUpGenius simply didn't exist in Japan.

Full-featured PTA tools require organizational-level adoption, Google Forms can't control capacity limits, and Chouseisan specializes in attendance tracking. As a result, actual operations involved handwriting names in LINE notes or cobbling together workarounds using Microsoft Forms. I wanted to fill this gap.

Thoughtful features for Japan's parent communities

• Names can be set to "show only the count" (awkwardness-aware mode)
• Cancellation deadlines can be set (prevents last-minute cancellations)
• Selection mode from member list (prevents spelling variations and duplicate entries)
• Automatic tally of entries per member (checks for uneven burden distribution)
• Coexistence with paper newsletters (QR codes and A4 printing)

Tech stack

Vite + React 18 / Firebase Realtime Database + anonymous authentication /
Cloudflare Pages. Capacity control uses dual protection with RTDB transactions and security rules. Admin authentication is implemented using a server-less adminProof method.

Current status

Beta version launched in July 2026. Future plans include dynamic OGP, raffle mode, and cancellation waitlist promotion. Feedback welcome.

https://kakarisan.com/