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kanta13jp1
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Why I Left Notion and Built My Own App with Flutter + Supabase

#notion #flutter #supabase #saas

Why I Left Notion and Built My Own App with Flutter + Supabase

The Moment I Realized Notion Wasn't the Problem

Late 2024, I hit Notion's free tier limit.

Five years of journals, KPI databases, freelance income tracking, reading notes, and project management — all in Notion. The day I got the upgrade prompt, I realized: "Paying $8/month won't actually fix my problem."

Notion's issue wasn't the price. It was the design philosophy.

Notion is built for team knowledge management. What I needed was a personal CEO dashboard. Those are fundamentally different products.

"Own Your Own Data" — The Decision

Before leaving Notion, I tried the alternatives.

  • Obsidian: Excellent local file management. But no live API integration or real-time data fetching.
  • Coda: More powerful than Notion, but the same "team-first design" problem.
  • Airtable: Great database UX. But KPI visualization still needs a separate charting tool.
  • Google Sheets: Fell back to this eventually. Bad on mobile, and I felt like I was giving up.

Conclusion after all of them: What I actually wanted, nobody had built yet.

So I built it myself.

Why Flutter + Supabase

The most important criterion: can I build the full stack alone?

Why Flutter — 3 Reasons

1. Web + iOS + Android from one codebase
Flutter Web for browser support → PWA for mobile. The Web quality is significantly better than React Native.

2. Dart's null safety
Dart forces null safety. For a solo dev who might not touch code for weeks at a time, this prevents the "why did this work before?" class of bugs.

3. Widget tree is intuitive
Column(children: [Text(), ElevatedButton()]) maps cleanly to how I think about UI. Coming from backend, this felt natural.

Why Supabase — 3 Reasons

1. PostgreSQL, not a NoSQL compromise
Firebase's NoSQL makes complex relational queries painful. Supabase is PostgreSQL — full relational freedom.

2. Edge Functions (Deno) make AI integration easy
LLM API calls, external service connectors — all handled in Edge Functions. Supabase's DB-to-EF integration is tighter than Vercel Functions.

3. Free tier that handles real production
Up to 50,000 MAU on the free plan. More than enough for the early stages of a personal product.

What I Built: Jibun Kaisha

The app is called Jibun Kaisha (Your Own Company).

The concept: run your personal life like a CEO running a company.

HR Dept       → Health, sleep, wellbeing tracking
Finance Dept  → Assets, liabilities, cash flow
Sales Dept    → Side income, freelance projects
Product Dept  → Skills, learning, AI University (206 providers)
Marketing     → Auto-post to X/Qiita/dev.to
Legal Dept    → Contracts, insurance, incorporation planning
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Six areas I was "kind of" managing in Notion, now with clear role separation and a single dashboard.

3 Technical Walls I Hit (and How I Solved Them)

Wall #1: Supabase's 50 Edge Function Limit

Supabase limits you to 50 deployed Edge Functions. Starting with one EF per feature, I hit 30+ fast.

Solution: Hub pattern. Created purpose-specific "hub" EFs — core-hub, tools-hub, ai-hub — that route by action parameter. Now 16 hub EFs cover 200+ actions.

Wall #2: Flutter Web Service Worker

PWA support was painful. flutter build web auto-manages Service Worker via flutter_bootstrap.js, but customizing cache strategy is non-obvious.

Solution: Direct customization of web/flutter_service_worker.js. Manual management of offline fallback and OGP image caching.

Wall #3: GitHub Actions Parallel Instance Conflicts

Running 10 parallel instances (VSCode / Win / 6×PS / Web / Mobile) all pushing to the same repo caused constant rebase conflicts.

Solution: Worktree isolation. Each instance works in its own git worktree and pushes via git push origin <branch>:main. For shared files like GROWTH_STRATEGY_ROADMAP.md: "skip → re-append" pattern on conflict.

6 Months Later

  • Users: 4 (alpha stage, pre-PMF)
  • AI University: 206 AI providers covered
  • Competitor tracking: 190 companies monitored
  • Blog posts: 120+ T-1 series posts on Qiita + dev.to
  • GHA workflows: 50+ CI/CD and automation scripts
  • Dev velocity: 10 parallel instances → 500+ commits/month

Should You Self-Build or Stay with Notion?

Was leaving Notion for Flutter + Supabase the right call?

Where it paid off:

  • Build exactly the features I actually need
  • Full data ownership
  • Technical learning as a byproduct
  • $0/month operating cost (OSS + free tiers)

The cost:

  • 3 months of initial build time
  • All bugs and infra are on me
  • UI polish still lags behind Notion's

Bottom line: If you're an indie developer who wants the perfect tool for your own workflow, building it is worth it. If you're using it with a team, Notion is still the rational choice.

→ Try it free: https://my-web-app-b67f4.web.app/

Source code is private (active development), but happy to answer technical questions in the comments.

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