What Was Broken (Basically Everything)

Here’s what was going wrong at the clinic:

• Double bookings constantly.
• No shows because people forgot their appointments.
• Doctor schedules weren’t visible unless you asked the front desk.
• Patients would call three times just to confirm a slot.

It was painful. For everyone.

So I made a quick list of what needed to happen:

• Real-time slot booking that actually blocks time
• Auto-reminders so people stop forgetting
• A simple UI for staff (no training manuals, just buttons that make sense)
• Doctor visibility without needing to ping reception every 5 minutes

Why I Picked Zoho Catalyst

I wasn’t in the mood to spin up servers or get lost in AWS land. Zoho Catalyst is basically a backend toolkit serverless, with built-in data storage, functions (like mini APIs), auth, cron jobs, etc.

Here’s what sold me:

• No server maintenance
• Built-in DataStore (basically a database without the database headaches)
• Catalyst Functions  write and deploy logic in minutes
• Cron jobs  great for appointment reminders

How I Actually Built It

The whole system has two main parts:

1. A basic web app (built with Angular) for the clinic staff and doctors.
2. The backend, entirely on Zoho Catalyst.

Backend Tables (DataStore)

• appointments: holds date, time, doctor ID, patient name, status
• doctors: working hours, buffer time, specialties
• patients: name, contact, visit history

Catalyst Functions

• Check availability before booking
• Confirm and save the appointment
• Cancel/reschedule logic
• Trigger SMS/email reminders

Cron Job

• Runs every evening at 7 PM
• Sends out reminders for the next day’s appointments

Frontend

• Reception staff can book or edit slots
• Doctors can log in and see their daily schedule
• Rescheduling is just a click and drag (no double data entry)

A Few Pain Points That Nearly Drove Me Nuts

1. Buffer Time Logic

Not all doctors run on the same schedule. Some wanted 10 mins between slots, some didn’t care. Took me a couple of failed deployments before I finally made buffer time configurable per doctor.

Lesson learned: Always ask doctors how they want to work before assuming.

2. Slot Collisions

I had to write a Catalyst function that basically yells “NOPE” if someone tries to book a slot that overlaps. Sounds simple, but the real-world edge cases (walk-ins, emergency blocks, overruns) made it messier than expected.

3. SMS Reminders > Email

We started with email reminders. No one read them. Switched to SMS with Twilio + Catalyst Function = magic. Patients actually showed up on time. No more “Oh I forgot” excuses.

Real Story: Monday Morning After Launch

So we launched it on a Saturday, did some dry runs, and then came Monday. Which is usually the worst day at the clinic.

By 11 AM, the receptionist looked… calm.

“This is the first Monday I haven’t had a panic attack.”

Appointments were flowing. Doctors weren’t yelling. No one was double-booked. People were getting reminders the night before and showing up on time.

Honestly, that one moment made the whole project worth it.

What Worked Really Well

• ✅ Catalyst’s Functions are fast booking feels instant.
• ✅ Zero server drama didn’t touch a single config.
• ✅ DataStore is simple not overkill, easy for staff to manage.
• ✅ Cron jobs are reliable great for daily reminders with logs for debugging.

What Could Be Better

• Documentation is just okay had to poke around a lot.
• Would’ve loved a pre-built UI module for auth instead of hand-rolling a login form.
• Deployment of functions takes a few seconds not a blocker, but noticeable.

What’s Next

• Patient portal (where they can book/reschedule themselves)
• Online payments for premium appointments
• Doctor-specific rules (e.g., some only work afternoons, others don’t see new patients)

I might even turn this into a template app and reuse it for other clinics still stuck in Excel hell.

Final Thoughts

I didn’t build the next Doctolib or Practo. But I did build something that solved real problems for real people  and I didn’t need a team of five or a six-month sprint to do it.

If you’re a dev trying to build a lean healthcare system (or anything workflow-heavy), Zoho Catalyst is actually worth trying. It’s not over-engineered, and it doesn’t get in your way.

And if you’re a clinic still running off spreadsheets stop. Please.