# How we cut an SA retailer's WhatsApp support response time by 87%

- Published by: Sitect (Pty) Ltd (https://sitect.co.za), written by Sitect Editorial Team
- Published: 2026-04-26
- Web page: https://sitect.co.za/insights/whatsapp-support-time-87-percent

> A field report from the NorthStar Retail engagement: what we built, what worked, what we'd do differently. 8,000 monthly messages, ~33-second median reply.

Read the full case study on our [Case Studies page](https://sitect.co.za/case-studies). This is the engineering-side post.

## The stack

- Twilio WhatsApp Business as the channel
- Laravel as the orchestration backbone
- pgvector on Postgres for RAG (we tried Pinecone first — overkill for the scale)
- gpt-4o-mini for triage, gpt-4o for full replies
- A small Vue dashboard for the support team to take over conversations

## What worked

The intent-classification step in front of the main reply path. We classify every inbound message into one of ~30 intents before deciding whether to fully answer, ask a clarifying question, or escalate. This made the system feel faster and more right than a single big prompt.

The "draft for human" mode that the team can toggle when they want eyes on every reply. About 12% of the team's time is now spent in that mode, mostly during sales weekends.

## What we'd do differently

We over-built the eval suite at the start. A simpler "every 20th reply gets reviewed by a senior agent, scored 1–5" loop would have caught the same drift earlier and cost less to maintain.

We under-invested in the take-over UX. The team had to refresh constantly for a week before we added live updates via Pusher. Listen to the support team early.

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Sitect (Pty) Ltd is an AI-first digital agency in Midrand, South Africa. Contact: 084 227 4264 (calls and WhatsApp), info@sitect.co.za.