HarshAI: I Built a Zapier Killer in 40 Days (Open Source)

Dev.to / 4/6/2026

💬 OpinionDeveloper Stack & InfrastructureSignals & Early TrendsTools & Practical Usage

Key Points

  • HarshAI is an open-source, self-hostable workflow automation project positioned as a lower-cost alternative to tools like Zapier and with a drag-and-drop plus node-based builder.
  • By day 40, the author reports building core workflow creation, an execution engine with real API integrations (e.g., Gmail, Twitter, Notion, Slack), test mode, error handling, and execution history.
  • The project also adds advanced capabilities such as cron scheduling, email notifications, an analytics dashboard, and webhook triggers with HMAC verification, retry logic, and event filtering.
  • Future milestones (days 41–90) focus on expanding integrations (including AI nodes for GPT-4/Claude/DALL-E), richer templates/marketplace features, and completing polish steps like testing, documentation, and Product Hunt launch prep.
  • The implementation uses a modern web stack (Next.js/React Flow frontend, Node.js/TypeScript backend, PostgreSQL via Supabase, Clerk auth, and Vercel deployment) to support a production-oriented automation platform.

HarshAI: I Built a Zapier Killer in 40 Days (Open Source)

40 days, 90 planned features, 44% complete. Here's what I built.

Why I Started

Zapier is expensive. Make.com has a learning curve. I wanted something:

  • ✅ Free & open source
  • ✅ Drag-drop builder
  • ✅ Self-hostable
  • ✅ Built for AI workflows

So I started building HarshAI.

What's Built (Days 1-40)

Phase 1: Core Builder (Days 1-15)

  • Drag-drop workflow builder
  • Node-based interface
  • Real-time connections
  • Mobile-responsive design
  • Template system

Phase 2: Execution Engine (Days 16-25)

  • Workflow execution engine
  • Real API integrations (Gmail, Twitter, Notion, Slack)
  • Test mode (no credentials needed)
  • Error handling
  • Execution history

Phase 3: Advanced Features (Days 26-35)

  • Background scheduler (cron)
  • Email notifications
  • Analytics dashboard
  • Webhook triggers (Days 31-35):
    • HMAC signature verification (Stripe-style)
    • Retry logic with exponential backoff
    • Analytics dashboard
    • Event-based filters

Phase 4: Template & Execution (Days 36-40)

  • Template marketplace - Save/share workflows
  • Multi-step workflows - If/else, loops, parallel execution
  • Error handling - Try/catch, logging, debug mode
  • Versioning - Auto-save, rollback, diff comparison
  • Rate limiting - Per-user quotas (4 tiers)

Tech Stack

Component Technology
Frontend Next.js 14, React Flow
Backend Node.js, TypeScript
Database PostgreSQL (Supabase)
Auth Clerk
Deploy Vercel (free tier)

What's Next (Days 41-90)

Phase 5: Integrations (Days 41-50)

  • 20+ pre-built API connectors
  • AI nodes (GPT-4, Claude, DALL-E)
  • Data transformation nodes
  • Enhanced scheduler
  • Template library (20+ workflows)

Phase 6: Polish (Days 51-70)

  • UI/UX improvements
  • Performance optimization
  • Comprehensive testing
  • Documentation
  • Video tutorials

Phase 7: Launch Prep (Days 71-90)

  • Beta testing
  • Community feedback
  • Bug fixes
  • Marketing site
  • Launch on Product Hunt

Try It Now

Live Demo: ai-workflow-automator.vercel.app

GitHub: github.com/harshaldevloper/harshai

Status: ✅ Production ready (Days 1-40 complete)

Want to Contribute?

Looking for:

  • 🐛 Bug reports
  • 💡 Feature suggestions
  • 🔌 Integration requests
  • ⭐ GitHub stars

The Reality

Building in public is hard. Some days I coded 8 hours. Some days I questioned everything. But 40 days in, I have:

  • ✅ 40/90 features complete (44%)
  • ✅ Production-ready webhook system
  • ✅ Template marketplace
  • ✅ Multi-step workflows with branching
  • ✅ Full version control
  • ✅ Rate limiting & quotas

Not bad for 40 days.

Follow along as I build to 100% in the next 50 days.

Disclosure: This is my project. Links above are direct (no affiliates).

ai #opensource #nocode #automation