How to Set Up SMS Auto-Reply for Missed Calls (UK Small Business Guide)

Setting up an SMS auto-reply for missed calls sounds technical — but it isn't. With the right platform, the entire process takes less than an hour, requires no coding or technical knowledge, and uses your existing phone number without any changes.

This guide walks you through exactly how to set it up, what decisions you'll need to make, and what good looks like at each step.

What You'll Have When You're Done

By the end of this setup, every person who calls your business number and doesn't get through will automatically receive a personalised SMS within seconds — 24 hours a day, 7 days a week, including weekends and bank holidays. You won't have to do anything after setup. The system runs itself.

Step 1: Choose Your Platform

The first decision is which missed call automation platform to use. Look for:

• UK phone number support (not all platforms handle UK numbers correctly)
• Sub-30-second response time
• Flat monthly pricing without per-message fees
• Full onboarding support — the platform should set things up with you, not leave you to figure it out
• Integrated booking calendar option

Vexlo is built specifically for UK trades and service businesses and includes all of the above. For a full comparison of what to look for, read our guide to the best missed call text back software for UK businesses.

Step 2: Onboarding Call (30 Minutes)

With Vexlo, the first step after signing up is a 30-minute onboarding call. During this call, your account manager will:

• Connect the system to your existing phone number
• Write your automated SMS message with you
• Set up your booking calendar if you want one
• Configure follow-up sequences (optional)
• Test the full system before going live

You don't need to prepare anything technical. Just know your phone number and have a rough idea of what you want the message to say. Everything else is handled during the call.

Step 3: Write Your Automated SMS

The automated SMS is the most important element of the setup. It needs to:

• Acknowledge the missed call directly
• Sound personal — not like a mass marketing message
• Include a clear next step (booking link or reply prompt)
• Be under 160 characters if possible

Your onboarding manager will help you craft this message. But if you want to prepare in advance, read our guide on what to say in a missed call text back for templates you can use.

Step 4: Set Up Your Booking Calendar (Recommended)

The booking calendar link in your SMS is what transforms a passive text response into an active conversion engine. When customers click the link, they see your availability and book a time that suits them — without any back-and-forth.

During onboarding, Vexlo will connect a booking calendar to your SMS. You set your available hours, buffer times between appointments, and any advance notice requirements. The calendar syncs with your existing Google or Apple calendar so bookings appear there automatically.

Step 5: Test Before Going Live

Before your system goes live, call your own number and let it ring to voicemail. Within seconds, you should receive the automated SMS. Check that:

• The message arrives within 10 seconds
• The wording looks correct and sounds right
• The booking link works and leads to the right calendar
• The confirmation email or notification system works

Your Vexlo onboarding manager runs this test with you before closing the call.

Step 6: Go Live and Monitor

Once the system is tested and approved, it's live. From that point, every missed call triggers an automatic SMS response. Most businesses see their first automated responses within the first hour of going live.

In the first week, monitor the system to make sure the message is converting well and tweak it if needed. Most businesses don't need to change anything — but if your response rate is lower than expected, a small adjustment to the message wording usually fixes it.

For a broader look at how this fits into the full automation picture, read our complete guide to replying to missed calls automatically.