Why SMS Still Cuts Through
Let's get something out of the way first. You've probably read a dozen pieces claiming "email is dead" or "SMS is dying because of WhatsApp." Neither is true. But here's what IS true: when it comes to reaching customers who actually read your message within minutes, SMS is unmatched.
98% open rate. Not 35%. Not 22%. 98%. And 90% of those opens happen within 3 minutes of delivery.
We process millions of messages a month across hundreds of clients. The numbers haven't changed much year on year. What has changed is the competition for attention — email inboxes are brutal, push notifications get dismissed, social ads get ignored. SMS cuts through all of that because the phone in someone's pocket buzzes and they look.
That doesn't mean you can send anything and expect results. The bar is high because the channel is so personal. Spam someone's phone and they'll hate your brand. Reach them at the right moment with the right offer and they'll buy.
This guide covers everything you need to run bulk SMS campaigns in 2026.
What "Bulk SMS" Actually Means
Quick definitions before we go further.
Bulk SMS is sending the same (or personalised variations of the same) message to hundreds or thousands of recipients simultaneously. This is different from conversational SMS (one-to-one messaging via a virtual number).
SMS marketing is using that channel for commercial purposes — promotions, loyalty programmes, re-engagement, event announcements.
Transactional SMS is slightly different — OTPs, order confirmations, delivery notifications. These aren't marketing, and the rules around them differ. We cover that in a separate post on transactional vs marketing SMS.
For this guide: we're talking about sending promotional messages at scale to opted-in subscribers.
Consent: The Thing That Actually Matters
Before you send a single message, you need consent. Not "we put it in our T&Cs" consent. Not "they ticked a box for offers" that was bundled with something else. Genuine, specific, freely given opt-in consent for SMS marketing.
In the UK, PECR is clear: you need explicit opt-in for marketing SMS to consumers, unless you're using the "soft opt-in" for your own existing customers. In the US, TCPA requires express written consent for most bulk SMS. In the EU, GDPR and ePrivacy apply.
How to build a properly consented list:
Keyword opt-in: "Text OFFERS to 60777 to receive exclusive deals." Simple, builds a list of people who actively want your messages, costs almost nothing to run.
Web forms: An SMS opt-in checkbox at checkout or account creation. Keep it separate from email consent. One checkbox = one permission.
In-store: A QR code or sign-up sheet. Make sure the consent language is visible, not buried in small print.
What does NOT work: buying phone number lists from data brokers. We know it seems tempting when you're starting out. But those lists have no valid consent, your delivery rates will be terrible, you'll rack up spam complaints, and if you're in the UK you're playing a game of "when does the ICO fine me" not "if."
Campaign Structure That Actually Converts
Once you have a consented list, here's how to structure a campaign.
Define the Goal — Specifically
"Drive more sales" is not a goal. "Generate £5,000 in revenue from our end-of-season clearance over 48 hours" is a goal. Specificity determines everything: the message, the timing, the offer, how you measure success.
Segment Your List
Don't send the same message to everyone. Even basic segmentation doubles performance:
- •Recent purchasers (last 30 days): upsell or cross-sell offers
- •Lapsed customers (90+ days): win-back offers with a bigger discount
- •High-spend customers: VIP early access before the general list
- •Location-based: relevant for in-store or regional promotions
The BulkSMSRates API supports segment-based sending with merge fields for personalisation.
Write the Message
This is where most campaigns go wrong. SMS copywriting is a specific skill. You have 160 characters per segment. Use them well.
The anatomy of a converting SMS:
- 1.Brand identification (sender ID or brand name in the message itself)
- 2.The offer — specific, with a number ("30% off" not "big savings")
- 3.Urgency — time or quantity limited
- 4.One clear action — a URL or keyword response
- 5.Opt-out — required by law in most jurisdictions
- •Delivery rate: DELIVRD status %. Target 95%+
- •Click rate: if you're tracking URLs with UTM parameters
- •Opt-out rate: STOP replies as a percentage of sends. Target under 0.5%
- •Revenue attribution: connect your SMS sends to sales data
- 1.Sign up at app.bulksmsrates.com — free account, no monthly fees
- 2.Check rates for your target countries
- 3.Set up your API integration or use the web portal
- 4.Build your first opt-in campaign
- 5.Send to your initial list, measure, iterate, scale
Bad SMS:
"Hi there! We have some amazing deals available right now. Check out our website for more information and savings you won't want to miss. Reply STOP to unsubscribe."
Good SMS:
"ACME: 30% off sitewide ends midnight. Code FLASH30: acme.com/flash. Reply STOP to opt out."
The second is shorter, specific, urgent, tells you exactly what to do, and still has room for a brand name. The first wastes every character it uses.
Timing: The Numbers Behind It
Based on aggregated data across thousands of UK campaigns processed through BulkSMSRates:
| Day | Best Conversion Window | Lower Performance |
|---|---|---|
| Tuesday | 10am–12pm | Before 9am |
| Wednesday | 10am–12pm | After 8pm |
| Thursday | 12pm–2pm | Evenings |
| Friday | 12pm–3pm | After 6pm |
| Saturday | 10am–1pm | Early morning |
| Monday | 12pm–2pm | First thing |
| Sunday | Generally avoid | — |
For retail and ecommerce, flash sale SMS sent between 10am and noon generate roughly 38% more conversions than equivalent evening sends. For hospitality (restaurants, venues), Friday 5pm–7pm works well for same-day bookings.
A/B test your timing. Sending 50% of your list at 10am and 50% at 6pm is basic optimisation that most brands skip but immediately shows what works for their specific audience.
Frequency and Fatigue
Here's the most common mistake from brands new to SMS: over-sending.
Two to four messages per month is the sweet spot for most retail and ecommerce businesses. More than that and opt-outs spike. Less than once a month and subscribers forget who you are.
The exception: transactional messages (order updates, delivery notifications) can happen as frequently as needed because recipients expect and want them.
For marketing: only send when you have something genuinely worth saying. "Tuesday feeling! 10% off today only" is not worth saying. A genuinely limited 24-hour flash sale tied to actual inventory is.
We've seen brands drop from 6 sends/month to 3 and watch their revenue per send nearly double because they stopped diluting attention. Quality over frequency, always.
Measuring What Matters
Your SMS provider should give you clean data on:
A healthy campaign: 96% delivery, 9–14% click rate, under 0.3% opt-out. If your opt-out rate is above 1%, you're either sending too often, your messages aren't relevant, or both.
Real ROI Numbers
A UK retail client sends roughly 80,000 segments per month. At our standard rate of £0.0300/segment (see pricing), that's about £2,584/month. Their last flash sale generated £47,000 in revenue over 24 hours. Even attributing only 25% to SMS, that's £11,750 from a £2,584/month spend.
That 4.5x return isn't unusual. The ROI on well-executed SMS marketing is genuinely remarkable — which is why brands that do it well keep doing it and keep scaling.
The catch is building the list. That takes time. Most brands that "don't get results from SMS" either bought a list, send irrelevant messages, or gave up before the list reached useful size.
Technical Setup
For simple campaigns: the BulkSMSRates web portal handles everything without coding.
For programmatic campaigns, scheduled sends, or integration with your CRM or ecommerce platform, use the HTTP API. It takes about 15 minutes to send your first message with a basic API call.
For very high volumes (100,000+ messages in a short window), consider the SMPP gateway which handles much higher throughput than the HTTP API.
Common Mistakes to Avoid
Using a numeric sender ID. Numbers like +44740012345 look like spam. Use your brand name as the sender where possible.
Forgetting opt-out text. Required by law, takes 27 characters: "Reply STOP to opt out."
Using shared URL shortener pools. bit.ly-style short URLs from shared domains often get blacklisted by carriers. Use branded short URLs or direct links.
Sending internationally without checking rates first. A message to the US costs very different from a message to the UK. Check rates by country before building campaigns.
Not cleaning your list. Numbers that haven't delivered in 6+ months should be removed. They drag down your delivery rate and waste spend.
Getting Started
SMS isn't magic. But with a consented list, good offers, and consistent sending, it delivers results that most other marketing channels genuinely can't match.