SalonHQ — Booking Confirmations That Actually Arrive

The Problem

SalonHQ had a WhatsApp booking confirmation system that appeared to work. The API returned success. No errors were logged. But clients weren't receiving confirmation messages — and nobody knew until clients called to ask if their booking was confirmed.

Silent failures are the hardest kind. Everything looks fine on the dashboard. The damage is happening invisibly.

The Five Failure Modes We Found

1. Template name mismatch — the template name in code differed by one character from the approved name in Meta Business Manager. API returned success anyway.
2. Named vs. numbered parameters — the template used named variables ({{name}}) but the API call sent numbered ones ({{1}}). Messages were sent but rendered blank placeholders.
3. Webhook verify-token — non-constant-time string comparison in the webhook handler caused intermittent verification failures under load.
4. Serverless timing bug — the WhatsApp send was called in a fire-and-forget async function after the HTTP response was returned. The serverless runtime killed the process before the Meta API call completed.
5. Phone number format — numbers stored with leading zeros instead of E.164 format (+234…). Meta rejected them silently.

The Fix

Each failure mode required a different fix. Template names copied directly from Business Manager. Parameters aligned to match the template format. Webhook handler updated with hash_equals(). WhatsApp send moved before the HTTP response return. All phone numbers normalised to E.164 at intake.

We also built an AI FAQ bot (using Claude via API) to handle inbound WhatsApp queries — pricing, availability, services — so the booking system worked both ways.

The messages weren't failing loudly — they were failing quietly. That's the dangerous kind.

The Result

100% delivery rate after the fixes. Zero silent failures in the 30 days post-deployment. The AI FAQ bot handles all inbound queries that previously went to staff manually.