Latest / Marketing Automation with Fexingo: HubSpot, Marketo, and Automated Customer Journeys / How Triggered SMS Boosts Email Open Rates by 18 Percent
Transcript
- Lucas: You get an SMS. It just says, 'Check your inbox — something landed from us.' That's it. No link. No offer. No urgency. Luna: I've actually received those from a few brands. I always open the email. Lucas: Exactly. And that's not an accident. It's a specific tactic called triggered SMS priming, and when it's timed right — roughly 60 to 90 seconds before the email hits — it lifted open rates by 18 percent in a controlled test I want to walk through. Luna: Whose test? Give me the source. Lucas: A mid-market e-commerce brand I'll call Junction Apparel. They sell DTC wardrobe basics — nothing flashy. They ran a two-month A/B test in Q1 2026 on their weekly promotional sends. The control group got the email at 10 AM Tuesday. The test group got a single SMS at 9:58:58, and then the email at 10 AM. Luna: So the SMS is literally a doorbell. 'Hey, mail's coming.' Lucas: Right. No discount code in the text. No link to click. Just a brand name and a tease. Junction saw an 18 percent lift in unique open rate and an 11 percent lift in click-through on the email itself. The SMS click-through rate was essentially zero — by design — but the email metrics improved significantly. Luna: And the SMS opt-out rate? I'd worry about annoying people. Lucas: They capped it at one SMS per week. Over the two months, the opt-out rate on the SMS channel was 0.3 percent — basically flat compared to their baseline. The key constraint: you cannot do this for every send. If you sms prime every email, you train people to ignore the text, and you spike opt-outs. Junction only primed their highest-intent sends — the ones that historically had the best conversion rates. Luna: So the threshold is frequency. Once a week max, and only for your top-tier campaigns. Lucas: That's the heuristic they settled on. And they tested the timing window, too. They tried a 30-second delay, a 60-second delay, and a three-minute delay. The 60-second window — call it 60 to 90 seconds — performed best. Thirty seconds felt too rushed; the email sometimes landed before the SMS, breaking the sequence. Three minutes was too long — people checked their email, saw nothing recent, and moved on. Luna: There's a cognitive bias at play here, right? It's not just about reminding someone. Lucas: Yeah, it's what I'd call the 'anticipatory gap.' You get a ping that something is coming. In that 60-second window, your brain builds a tiny expectation. When the email arrives, you're more likely to open it because you're resolving that anticipation. It's similar to how a trailer makes you more likely to watch the movie — you already have a hook. Luna: And the SMS itself has to feel native. If it looks like a spam blast, you lose the effect. Lucas: Absolutely. Junction used the same sender ID they use for all their transactional SMS — order confirmations, shipping updates. So it came from a familiar number, not a short code they only use for marketing. That familiarity lowered the weirdness factor. Luna: So the setup in a platform like HubSpot or Marketo — how do you actually build this? I've used both, and the SMS trigger isn't always obvious. Lucas: In HubSpot, you'd create an sms only send with a delay action set to 'send immediately,' and then a separate email send scheduled for 60 seconds later. Both triggered from the same enrollment event — say, a list membership or a property change. The key is that the SMS sends first and then the workflow pauses for 60 seconds before the email fires. In Marketo, it's similar: a 'Send SMS' flow step followed by a 'Wait' step of one minute, then 'Send Email.' Luna: But the SMS channel itself is an added cost. Most SMS platforms charge per segment. If you're sending to a list of 100,000, that's 100,000 SMS messages just to prime an email. Lucas: It's a real consideration. Junction's average SMS cost was about half a cent per message, so 100,000 sends is $500 per campaign. They only did it for their top two campaigns per month, so about $1,000 in incremental SMS cost. Against the revenue lift from the email — which they measured at roughly 7 percent higher conversion rate on the primed group — it was easily positive. Luna: But for a smaller brand, that $500 might be a real budget hit. What's the minimum list size where this makes sense? Lucas: Junction's internal analysis suggested that if your email send is at least 20,000 subscribers and your email-driven revenue per campaign is over $10,000, the ROI is positive. Below that, the SMS cost eats too much of the lift. So this isn't a play for a startup with a 2,000-person list — you'd need a more targeted approach, like sms priming only your VIP segment. Luna: I want to talk about the content of the SMS itself. What actually worked for Junction? You mentioned it was just a teaser. Can you read me one of the actual templates they used? Lucas: Sure. One version was: 'Junction here — we just dropped a new color in your favorite fit. Check your email for the first look.' That's it. No link. The email contained the full campaign. Another version for a sale: 'Heads up — your early access link is about to land in your inbox. 60 seconds.' Very direct. Luna: The '60 seconds' bit is smart. It sets the exact expectation. Lucas: They tested that against a vague 'coming soon' version, and the specific time reference improved email open rate by an additional 4 percent. So the exact timing cue matters. Luna: I'm going to play devil's advocate for a second. If everyone starts doing this, won't users get numb to it? The anticipatory gap closes once the pattern becomes predictable. Lucas: That's the risk, and it's why frequency control is so important. If you get sms primed every Tuesday at 10 AM for six months, you stop feeling anticipation. You feel annoyance. Junction's data actually showed a slight decay in the lift after the eighth week — the open-rate advantage dropped from 18 percent to about 13 percent. So they started rotating which campaigns got primed and varying the send day. Luna: Variety as a defense against habituation. Makes sense. Lucas: They also introduced a 'skip week' every fourth week — no SMS at all for the top campaign, just the email. That reset the lift back to the original 18 percent level. Luna: So the playbook here is: pick your highest-intent campaigns, send a single SMS with a timing cue 60 seconds before the email, cap frequency at once a week, and insert a skip week every month. Lucas: That's the core recipe. And test it on a segment first — maybe your top 10 percent of engaged subscribers — before rolling to your full list. Luna: You know, it's funny — we spend so much time on complex personalization and ai driven content, but sometimes a simple behavioral trigger like this outperforms all the fancy stuff. Lucas: Right. And that's actually a good place to mention something about how we think about this show. We deliberately don't run ads on these episodes, because we want to keep the focus on tactics that actually work, not promotional fluff. If you find these detailed breakdowns valuable — and if you've ever tested something you heard here — the best way to support that choice is at buy me a coffee dot com slash fexingo. No pressure, just a way to keep it ad-free. Luna: Yeah, it's a small thing that makes a big difference for us. Feels good knowing the content stays clean. Lucas: Alright — back to the sms email combo. One more finding I want to highlight: Junction also measured the impact on unsubscribe rate. The email-only group had a 0.12 percent unsubscribe rate. The sms primed group had 0.11 percent. Statistically identical. So the SMS didn't drive people away. Luna: That's crucial. Marketers often worry that adding a channel will increase churn. But if the SMS is genuinely valuable — a heads-up, not a hard sell — it can be additive without being intrusive. Lucas: Exactly. And the SMS itself has to provide value beyond just 'look at your email.' Junction tested a version that included a small preview of the email content — like 'We just added navy to our bestselling jacket. Email coming now.' That version actually saw a 2 percent lower email open rate, possibly because the SMS satisfied some curiosity. The pure teaser — no content — worked best. Luna: So don't spoil the surprise. The SMS should create a gap, not fill it. Lucas: That's a great way to sum it up. Create the gap, then close it with the email. Luna: Alright, I'm actually going to try this with our own newsletter. Two thousand subscribers, but I'll start with the top 200 engaged. Lucas: Let me know how it goes. And if you see a lift, that's the kind of concrete result we love to hear about. Luna: Will do. For now, I think we've given listeners a very specific, testable tactic. SMS before email, 60-second gap, once a week, no spoilers. Lucas: That's the episode. Thanks for listening — we'll be back next week with another deep dive into what's actually working in marketing automation.