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Appcitas

10 years old. Still running. An AI agent books your appointments via WhatsApp.

SaaS WhatsApp AI HealthTech Visit site

The 10-Year Journey

Appcitas started in 2015 when I was just getting started in software development. A simple idea: help Colombian clinics and service businesses manage appointments without expensive software.

The problem: Clinics, dental practices, beauty salons — all drowning in appointment chaos. Phone calls, WhatsApp messages, missed appointments, double bookings.

What Appcitas Actually Does

A B2B SaaS platform where patients book, cancel, and reschedule appointments directly through WhatsApp — powered by an agentic AI.

  • AI booking agent — Handles natural conversations in Spanish, books and cancels appointments using 7 custom tools
  • Full WhatsApp integration — Two-way messaging via Meta Cloud API, each business gets their own WhatsApp Business Account
  • Automated reminders — Daily scheduled Lambda sends WhatsApp template messages 24h before appointments
  • Multi-tenant — Each organization isolated by phone number, conversation history stored per-tenant in DynamoDB
  • Public booking pages — Whitelabel booking widgets accessible by organization slug
  • CX analytics — NPS, CSAT, NEV surveys collected post-appointment with keyword analysis

Technical Architecture

Fully serverless on AWS:

  • Lambda functions for API, webhooks, NLP processing, and CRM
  • SQS queues for async message processing pipeline
  • DynamoDB for conversation state (24h TTL, 20 message window)
  • PostgreSQL/Supabase for relational data via Sequelize
  • EventBridge Scheduler for CRM scheduled messages
  • Wompi payment gateway integration (Colombian payments)

The WhatsApp flow: Meta webhook → parse + tenant lookup → SQS → AI agent with tools → response queue → send via Graph API.

Evolution

  • v1 (2015-2017): PHP + MySQL. Classic LAMP stack.
  • v2 (2017-2019): Node.js + MongoDB. WhatsApp became the killer feature.
  • v3 (2019-2024): Node.js + PostgreSQL + AWS serverless. Rasa NLU for chatbot.
  • v4 (2024-Present): Agentic AI replaced Rasa. Full tool-calling agent.

What I Learned

  1. WhatsApp is king in LATAM — Email reminders had 20% open rates. WhatsApp has 95%+
  2. Side projects need patience — Took 5 years to get meaningful revenue
  3. Simple beats complex — The features that stuck were the simple ones
  4. AI actually works now — Agentic AI with tools handles edge cases Rasa never could

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