Email and SMS retention strategy: 6 workflows to copy

Winning a new customer costs more than keeping one who already knows you. Even so, many small businesses put almost all their effort into acquisition and leave their customer relationships to chance.

You don’t need complicated campaigns to retain customers. A few automated workflows that say the right thing at the right time, through the right channel, are enough.

In short: an email and SMS retention strategy relies on 5 or 6 automated workflows: welcome, post-purchase, abandoned cart, birthday, reactivation and payment reminder. Email is for explaining and SMS for anything urgent, at most once per workflow. Tools like Mailrelay, Brevo or Klaviyo combine both channels in the same automation. In Mailrelay you can do it on the free account too, with up to 80,000 emails a month and 20,000 contacts, and add SMS with prepaid credit.

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How do you design a retention strategy using email and SMS?

Set your goal and how you’ll measure it. For example, more customers buying again within 90 days, or fewer cancelling your service.
Gather permission and data. For email, consent. For SMS, the mobile number and its own permission. Plus the data that will trigger each workflow: sign-up date, purchases or birthday.
Choose the workflows. You don’t need to set them all up at once. Start with one or two and add the rest once they work.
Split the channels. Email does the heavy lifting: it explains, shows products and adds value. SMS is kept for alerts that can’t wait.
Measure and adjust each workflow separately. See which email gets opened, where people drop off, and whether the SMS adds anything or just costs money.

These are the six most useful workflows for a small business:

Workflow	When it starts	Email	SMS	Entry point in Mailrelay
Welcome	When the subscription is confirmed	2-4 emails over 1-2 weeks	Not usually needed	“When subscriber signs up using a signup form”
Post-purchase	After the purchase	Thank you, product use, review and related product	Optional: shipping notice	“When a subscriber is added to a group” (customers group)
Abandoned cart	When the cart is abandoned	1 hour and 48 hours later	One after 24 hours	“When a cart is abandoned” (WooCommerce plugin)
Birthday	On the date, before or after	Greeting and gift	Optional: gift reminder	“When it’s the subscriber’s birthday”
Reactivation	After months without opening	2-3 emails	No: if someone doesn’t open your emails, don’t bother them on another channel without permission	Segment by “Subscriber score” and “When a campaign is received”
Payment or renewal reminder	Before and after the due date	Advance notice, due-date notice and late notice	On the due date	“When a subscriber is added to a group” (pending payment group)

The 6 retention workflows, one by one

1. Welcome

This is the first workflow you should set up, because it arrives when interest is at its peak. Introduce your brand, answer the most common questions and explain what you’re going to send. In Mailrelay it starts when the contact confirms their subscription.

If you run a small business and don’t know where to start, set up a short introduction workflow first. Use it to answer the most common questions: that reassures your customers. It also shows them there’s a way to get in touch with your company, and that builds trust. My advice: before you write it, go through last month’s emails and calls and note down the five questions that come up most. That’s your first workflow.
Jose Argudo, CMO at Mailrelay

You’ll find ideas and examples in welcome email and, for a longer series, in lead nurturing.

2. Post-purchase

After buying, the customer wants to know everything is going well. A useful sequence:

thank you and order details, the same day;
usage tips, a few days after delivery;
a review request, after a week;
a related product, after 2 or 3 weeks.

If you sell products that run out, like cosmetics or coffee, add a replenishment reminder for when you estimate they’ll be finished.

In Mailrelay, the automation doesn’t detect the purchase on its own. Add the buyer to a customers group, for example by import, through the API or with Make, and use the “When a subscriber is added to a group” entry point.

3. Abandoned cart

A short sequence: an email after an hour, an SMS the next day for anyone who hasn’t come back, and a final email after 48 hours. If your store runs on WooCommerce, the Mailrelay plugin starts the workflow with “When a cart is abandoned”. Anyone who buys during the sequence isn’t removed automatically: you have to take them out.

You’ll find the details in abandoned carts and in the WooCommerce guide.

4. Birthday

It’s simple and always well received. Store the date in the “Birthday” field and choose whether the email goes out a few days before, on the day or after. If you give a discount as a gift, a short SMS before it expires can remind them.

You’ll find templates to copy in birthday email.

5. Reactivation

For contacts who haven’t opened anything in months. In Mailrelay you can find them with a segment by “Subscriber score”, for example 2 stars or less, and send them 2 or 3 reactivation emails. If they don’t respond, take them out of your regular sends: they hurt your sender reputation.

You’ll find the sequence in winback campaign and how to segment by score in lead scoring.

6. Payment or renewal reminder

For subscriptions, fees or recurring services: one notice a few days before, another on the due date and one or two afterwards if the payment doesn’t arrive. SMS works well here, because it’s a notice the customer appreciates.

In Mailrelay, add the customer to a group when the date is getting close and use “When a subscriber is added to a group” with delays between notices. You’ll find 20 example messages in payment reminder.

Infographic: 6 email and SMS retention workflows: welcome, post-purchase, abandoned cart, birthday, reactivation and payment reminder

How do you design a funnel combining email and SMS?

Each stage of the funnel has its channel:

Stage	Email	SMS
Acquisition	Welcome and useful content	No
Conversion	Nurturing, case studies and offers	Only for a real deadline
Purchase	Confirmation and post-purchase	Shipping or delivery notice
Repeat purchase	Related product and replenishment	One-off reminder
Reactivation	2-3 reactivation emails	No

Five rules so SMS adds value instead of annoying people:

Permission. Consent for email doesn’t cover SMS: ask for both separately.
One per workflow at most. If a message can wait, it’s better by email.
Timing. Send SMS during business hours, never at night.
No offer in every message. If the discount always comes, customers learn to wait for it.
Cost. Every SMS costs money. Use it where it makes a difference: payment reminders, carts and deadlines.

To decide who gets the SMS, you can rely on the subscriber score. For example, send it only to people with 3 stars or more who still haven’t responded to the email. There’s more on when to use each channel in Email, SMS or WhatsApp?.

How to measure retention

Repeat purchase rate: the percentage of customers who buy again within a period.
Churn: the percentage of customers who stop buying or cancel.
Customer lifetime value: what a customer brings you over the whole relationship.
Results per workflow: opens, clicks and conversions for each email and each SMS.

Compare each workflow with what happened before you set it up. If a workflow hasn’t improved anything in two or three months, change it or remove it. There’s more on building loyalty in customer loyalty.

Tools to combine email and SMS in the same automation (November 2026)

Tool	SMS in the same workflow	Free plan	Worth knowing
Mailrelay	Yes, on every plan, with SMS credit	80,000 emails a month and 20,000 contacts	Automations on the free account too, and human support
Brevo	Yes, with SMS credits	300 emails a day	Free plan automations have a contact limit
Klaviyo	Yes	250 profiles and 500 sends a month	Strongly geared to online stores
ActiveCampaign	Yes, with the paid SMS add-on	No free plan	SMS only with the add-on
Mailjet	Not in its automations; through Zapier	Free plan with a daily limit	SMS is separate

How Mailrelay helps you

Email and SMS in the same automation, on every plan, including the free account.
Entry points for each workflow: form, group, birthday, abandoned cart, open or click.
Conditions and delays to separate people who respond from people who don’t.
Subscriber score, from 1 to 5 stars, to segment by level of interest.
WooCommerce plugin for abandoned carts.
Up to 80,000 emails a month and 20,000 contacts for free, with human support on every plan.

Email and SMS in a single tool

Up to 80,000 emails a month and 20,000 contacts for free, automations on every plan and SMS with prepaid credit.

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Frequently asked questions

Which workflow should I start with?

The welcome one: it arrives when interest is at its peak and works for any business. If you have an online store, the next one is abandoned cart.

How many SMS is it reasonable to send?

One per workflow at most, and only for alerts that can’t wait. Everything else goes by email.

Do I need separate permission to send SMS?

Yes. Consent to receive emails doesn’t cover SMS. Ask for both separately in your form.

What’s the difference between retention and loyalty?

Retention measures whether the customer stays, for example whether they buy again or renew. Loyalty aims for them to stay because they want to and to recommend you. The workflows in this article serve both purposes.

Can I do all this with a free Mailrelay account?

Yes. Automations are included in the free account. To send SMS you only need to buy credit.