The problem every invoicing tool runs into
Raising the invoice was never the hard part. Getting it paid on time is. A reminder emailed to a customer lands in a crowded inbox next to newsletters, receipts and everything else, and it is easy to leave for later, and later, until a 30-day invoice quietly becomes a 50-day invoice. The invoice is not disputed. It is simply not being seen.
For a small business, that gap is a cash-flow problem before it is anything else. Money that is owed but unseen cannot pay your own suppliers. the invoicing platform needed a reminder channel that gets read quickly, without asking users to make awkward phone calls chasing payment.
Why SMS, not more email
The case for SMS as a reminder channel is not opinion, it is in the channel data. Text messages are opened at a rate email cannot approach, and they are read almost immediately rather than hours or days later. For a payment reminder, that is the whole job: get the invoice back in front of the customer at a moment they can act on it.
Figures are widely reported industry averages for opt-in business messaging, not the invoicing platform's own results. SMS open rates are typically cited at around 98% against roughly 20% for email. Open rate measures messages viewed on the device, so treat it as a measure of visibility rather than deep engagement.
Speed matters as much as reach. A reminder that is read within minutes of arriving is a reminder that gets actioned while the customer still has their phone in hand, and the pay link is right there in the message.
Around 90% of text messages are read within three minutes of delivery, while email is commonly read hours later or missed entirely. Source: aggregated 2026 SMS industry benchmarks.
How the invoicing platform's SMS reminders work
The setup is deliberately plain, because a message about money should feel factual and calm, never like a marketing blast. the invoicing platform connects Smart Follow Ups and sends reminders by SMS alongside email.
Due-date nudge
On the day an invoice falls due, the customer gets a short text with the business name, the amount, and a link to pay.
Overdue follow-up
If it is still unpaid a few days later, a firmer reminder goes out, again with the amount and pay link.
Pay by link
Every reminder carries a direct link to settle the invoice, so there is no hunting for the original email.
Stops on payment
Once an invoice is marked paid, the sequence stops automatically, so no one is chased for money already sent.
A simple two-step reminder flow
Illustrative sequence. Timing is configurable to suit your payment terms.
Kept compliant by design
Payment reminders to a customer about an invoice they owe are transactional service messages, not marketing, so they sit outside most PECR marketing-consent rules. Every reminder identifies the business sending it, states the amount and reference, and gives the customer an easy way to reply or query. That line, factual reminder versus marketing nuisance, is built into how the messages are written. For the full detail on where transactional ends and marketing begins, see the PECR and GDPR SMS compliance guide.
Do the same for your business
You do not need to be an invoicing platform to send payment reminders by text. Any UK business that raises invoices can use the same approach with Smart Follow Ups: automated, factual reminders with a pay link, that stop as soon as the invoice is settled.