Letlify

The Problem

Coordinating professional meetings, advisory sessions, and client consultations remains plagued by frustrating back-and-forth communication, timezone conversion errors, and double-booking risks.

Most legacy scheduling tools treat the appointment as a generic, detached form. They impose heavy loading lag, deliver poor mobile experiences, and fail to incorporate meaningful business context—such as pre-meeting qualification questions, custom agendas, and automated multi-channel follow-ups.

The Solution

Letlify reimagines online appointment booking by delivering an intuitive, lightning-fast scheduling platform engineered for founders, consultants, and modern service teams. Hosts can share polished booking pages, embed low-latency widgets directly onto their existing websites, and connect their personal or enterprise calendars for real-time bi-directional synchronization.

With automated timezone detection, configurable buffer intervals between sessions, custom intake questionnaires, and automated email/SMS reminders with calendar invite attachments, Letlify eliminates scheduling friction while drastically reducing meeting no-show rates.

My Role

As Lead Architect and Product Engineer, I led product strategy, core system design, and full-stack implementation:

• Designed a high-throughput availability calculation engine in TypeScript that computes complex host working hours, external busy blocks, and buffer rules with sub-50ms latency.
• Implemented robust concurrency controls using PostgreSQL temporal range constraints (tstzrange with btree_gist exclusion) and Redis advisory locks to mathematically eliminate double-booking race conditions.
• Engineered bi-directional calendar synchronization pipelines using idempotent webhook ingestion for Google Calendar and Microsoft Graph with delta-token incremental fetching.
• Built embeddable, responsive booking widgets and interactive web components optimized for instantaneous load times and high conversion across desktop and mobile devices.

Technology

• Full-Stack Framework: Next.js (App Router, TypeScript) utilizing Server Components, Server Actions, and edge-ready API routes for transactional integrity.
• Database & Concurrency: PostgreSQL for relational booking state with range exclusion constraints, coupled with Redis for distributed locking and availability caching.
• Calendar Integrations: Webhook-driven event ingestion for Google Calendar and Microsoft Graph with idempotent sequence reconciliation.
• Payments & Workflow: Stripe integration for paid consultations, paired with automated multi-channel notifications (dynamic .ics file generation and Google Meet / Zoom link injection).
• Design System: Tailwind CSS crafted with custom editorial design tokens for clarity, responsiveness, and trust.

Outcome

• Powers instant appointment bookings with over 99.9% uptime and zero double-booking discrepancies.
• Delivered sub-100ms availability calculation and calendar slot generation, reducing guest booking drop-offs significantly.
• Successfully deployed as the live booking infrastructure powering client and advisory consultations directly on victoryunusa.com/book.