✨ Try now at issho.dulapahv.dev
Issho (一緒) means "together" in Japanese - and that's exactly what this app is about. It's a real-time collaborative calendar that lets you and your friends visually mark your availability and instantly find the perfect time to meet, without the endless back-and-forth messages or creating yet another account.
The Problem
After finishing my studies in the UK, I had a precious 2-month window to visit family and friends in Thailand before returning to work. I wanted to make every moment count, planning meetups efficiently to see everyone I'd missed.
But coordinating was a nightmare:
- "Are you free next week?"
- "Which days work for you?"
- "How about Thursday? Oh wait, someone can't make it..."
- Creates a poll
- Half the group doesn't respond
- Repeat for every single meetup
Sound familiar? I was spending more time planning than actually meeting people. There had to be a better way.
The Solution
Issho was born from this frustration. Instead of exchanging dozens of messages, what if everyone could just paint their availability on a shared calendar? No signup, no downloads, just pure simplicity.
Here's how it works:
- Create a calendar - Get a unique 8-character ID and 6-digit PIN instantly
- Share with friends - Send them the credentials (one message!)
- Everyone marks their availability - Just click and drag
- Find overlaps instantly - The perfect time reveals itself
Key Features
Real-time Collaboration - See updates instantly as friends mark their availability. No refreshing needed.
Smart Analytics - The app automatically shows you the best meeting windows, individual availability percentages, and when everyone's free.
No Account Required - Share calendars with just an ID and PIN. Privacy without the hassle of signups.
Mobile-First Design - Works perfectly on any device with responsive UI and intuitive touch controls.
Technical Highlights
Built with modern web technologies for a seamless experience:
- Next.js 15 for blazing-fast performance
- Supabase Realtime for instant synchronization
- Prisma + PostgreSQL for reliable data storage
- Vercel BotID for invisible bot protection
- React Big Calendar for familiar, intuitive interface
The app features deterministic color generation (same name = same color every time), and automatic cleanup of unused calendars after 90 days.
Impact
Since launching, Issho has helped coordinate many meetups. Users love the simplicity:
"Finally, scheduling that doesn't require 20 messages"
"This app is much easier to use than I expected"
The 2 months in Thailand? I managed to see everyone I wanted to, with minimal planning overhead. Issho had already paid for itself.
Open Source
The entire project is open source on GitHub under the Apache-2.0 license. Feel free to explore the code, suggest features, or contribute!
Try it yourself at issho.dulapahv.dev - no signup required, of course.