Slotify is a production-grade scheduling and booking platform built to deliver the smooth, low-friction experience users expect from modern tools like Cal.com, while keeping the stack lean, type-safe, and developer-friendly.

It is not just a booking page. It is a complete scheduling system that covers public booking links, timezone-safe availability, booking lifecycle management, calendar sync, payments, emails, SEO, and robust webhook processing.

Why I Built Slotify

Most scheduling products solve only one part of the workflow. They either focus on calendar UI, payment collection, or notifications, but rarely connect all parts in a reliable way.

With Slotify, the goal was to build an end-to-end scheduling engine where:

• A host can create event types and share a public link
• A guest can discover accurate time slots in their local timezone
• A booking can be safely created without race conditions
• Payments can be captured and verified securely
• Email notifications and delivery states are fully tracked
• SEO and public discoverability are ready by default

What Slotify Supports (Cal.com-Style Feature Coverage)

Slotify is designed to perform the core capabilities expected from a complete scheduling platform:

• Public scheduling pages by host username and event type
• Timezone-aware slot generation across regions
• UTC-first storage strategy for consistency
• Booking lifecycle operations: create, cancel, and reschedule-safe handling
• Host-side booking visibility and management APIs
• Google Calendar integration with automatic Google Meet link generation
• Secure auth flows with Better Auth + Google OAuth
• Subscription billing with Razorpay order creation and verification
• Webhook-driven payment reconciliation with idempotency safeguards
• Transactional booking emails through Resend
• Delivery-status synchronization through Resend webhooks
• SEO baseline included: metadata, structured data, robots, sitemap, manifest

Product Experience

1. Public Booking Flow

A host shares a public profile/event URL. Guests can select an event type and choose from dynamically computed available slots.

The slot engine is timezone-sensitive:

• Host availability is computed in host timezone
• All date-time values are persisted in UTC in the database
• Attendees view options in attendee-local timezone

This approach prevents DST confusion and cross-region time mismatches.

2. Booking Lifecycle

After selecting a slot, a booking can be created and managed through APIs that support:

• New booking creation
• Cancellation flows (host and public-safe endpoints)
• Update operations with conflict-safe behavior

Concurrency is handled with database-level guarantees, so duplicate or conflicting bookings are prevented under load.

3. Calendar and Meeting Integration

Slotify integrates with Google so booked sessions can be reflected in calendar workflows and include Google Meet join links when needed.

Token refresh and reconnection edge-cases are handled to avoid silent integration failures.

4. Billing and Subscription Layer

For paid scheduling or premium plans, Slotify integrates Razorpay with:

• Order creation endpoint
• Signature verification endpoint
• Webhook processing for payment lifecycle events

Webhook handlers validate signatures and apply transactional row-level locks to ensure idempotent updates and avoid double-processing.

5. Notification Reliability

Slotify uses Resend for booking notifications and tracks email delivery lifecycle using a dedicated webhook endpoint.

Supported states include sent, delivered, failed, bounced, complained, and suppressed. This provides observability that many scheduling clones ignore.

Technical Stack

Slotify is built with a modern production stack:

• Next.js 16 App Router + React 19 + TypeScript
• Tailwind CSS v4 + Radix/shadcn UI primitives
• Prisma 7.5 + PostgreSQL
• Better Auth with Google OAuth
• Razorpay (payments)
• Resend (email)
• Bun runtime and package manager

API Surface

The project exposes a practical API layer for core scheduling operations:

• Auth handlers
• Availability discovery
• Booking create/read/update/delete
• Public cancellation endpoint
• Event type CRUD
• Onboarding completion
• Pricing retrieval
• Subscription order/verification/webhook endpoints
• Email delivery webhook endpoint

This structure keeps public and authenticated flows clearly separated while preserving a consistent domain model.

SEO and Discoverability

Slotify includes foundational SEO setup out of the box:

• Global metadata definitions
• Home page metadata and JSON-LD structured data
• Robots configuration
• Sitemap generation
• Manifest configuration

With a proper production base URL configured, canonical links and crawlers behave as expected.

Architecture Decisions That Matter

UTC-First Data Model

Time values are persisted in UTC for deterministic storage and querying. Presentation is shifted to user-local timezone at the edge.

Idempotent Webhook Processing

Webhook endpoints are signature-validated and transaction-protected. This prevents replay and duplicate side effects.

Graceful Degradation

If optional integrations are missing (for example email keys in local setups), core app behavior degrades safely rather than crashing unexpectedly.

Local Development Flow

The setup remains straightforward:

1. Install dependencies with Bun
2. Copy env template and fill required secrets
3. Generate Prisma client and run migrations
4. Start development server

This allows contributors to move from clone to running environment quickly.

Production Readiness Checklist

Before go-live, Slotify expects:

1. Complete env variable setup
2. Correct Google OAuth redirect configuration
3. Razorpay webhook setup with matching secret
4. Resend sender + webhook setup with matching secret
5. Applied production migrations
6. Correct public app URL for SEO surfaces
7. Verification of robots, sitemap, and manifest endpoints

Final Thoughts

Slotify demonstrates how to build a complete scheduling platform, not just a booking form.

From timezone correctness and calendar sync to payments, emails, webhooks, and SEO, the system is structured for real-world usage and scale. If you are exploring how to build a modern scheduler with a clean TypeScript-first stack, Slotify is a practical blueprint.