Postscript vs Klaviyo for Shopify Email and SMS

Which SMS activity does your email flow need?

Take one follow-up you would send differently after a text. Say you launch a restock by SMS first. You want to email subscribers who received that text and haven’t clicked by the time the email goes out. A list of everyone who has an SMS subscription is too broad. Your email audience needs to know who received that specific text and whether each person clicked it before the email cutoff.

Postscript gives that follow-up as an example of using its Klaviyo integration. Its setup guide also documents making Postscript segments from email received or clicked events in Klaviyo and making Klaviyo segments from links clicked in a particular Postscript campaign. Ask the specialist to build your exact audience in Klaviyo. A live demo of a click reaching the profile shows one part of the job. You still need to see how the flow limits itself to recipients of the right campaign and when it checks for a click. Postscript’s integration examples and Postscript setup guide.

Have the vendor show three email-eligible test profiles. One receives and clicks the restock text. One receives it and leaves it alone. The third belongs to the SMS list and was outside the campaign audience. At your planned email time, only the second profile should qualify. Then try a click just before the cutoff. Look at the timestamps in both systems and the email audience as it stood when the rule ran. If the vendor can only show the final audience, ask how your team would find out why someone landed in it.

Keep the split on the shortlist if the team can reproduce that audience at the time it actually sends and can point to the SMS work it wants Postscript to handle. If a split requires your team to reconcile audiences by hand every launch, ask Klaviyo to show the same rule with both channels on its platform. A simple follow-up that your team can maintain may be more valuable than a specialist for a workflow you rarely use.

Download the buying worksheet

Start with the email program you already depend on

If your team already runs checkout recovery in Klaviyo and wants to add a text, show what you would gain by moving SMS out before you change tools. Klaviyo's recovery instructions describe starting with email and adding SMS to the flow. That makes it a sensible first test when the same marketer looks after both channels and wants one place to review the delays and order checks.

Compare Postscript when the store has a separate person or agency responsible for SMS and wants them to control its own program. In that setup Klaviyo can stay responsible for recovery email. The hard part is making both teams use the same definition of an abandoned checkout and giving the SMS sender a usable record of a completed order.

Ask each vendor to reproduce the one email you most want to keep. Include its checkout link, the intended wait and the rule for an order received after the shopper entered the flow. If the proposed split requires replacing working email or moving its customer data just to add a text, ask what that extra migration buys. If the split keeps that email and gives your SMS operator a useful capability they can demonstrate, run the two tests below before comparing price.

Find every place an abandoned checkout can send from

Open the current flow inventory before you build the replacement. Include Shopify's own abandoned checkout reminder, live email and SMS flows, and anything still sending through a previous app. Klaviyo's setup guidance warns about overlap with store-platform reminders. Copying a flow without finding its existing sender can leave both in operation.

Write down who owns each action from the store event onward. A single Klaviyo flow might own both sends. In a split proposal, record which event feeds the email, which feeds the SMS, and how both systems learn about the order. Ask the person who will maintain the flows to check this in the account. A platform can receive the event without any particular message using it.

Postscript's Shopper Automations documentation names the triggers it takes over for subscribers in the test group, including cart, checkout and replies. It also says activating Shopper Automations disables active Infinity Testing Automations. If that is part of your proposal, ask for the exact list of flows that would turn off and the subscriber group it changes. The result of a demo with one group does not establish the fate of every shopper on your list.

Keep a short inventory that names the event, channel, live sender, replacement sender and owner. Mark what remains active for shoppers outside the test group. If two tools are listed for one send, resolve which one should own it before anyone schedules a migration.

Test a completed order alongside an abandoned checkout

Run the timed purchase exercise above with two eligible test shoppers. They start the same kind of checkout and enter the same recovery path. One places and pays for a test order between the email and the scheduled text. The other leaves checkout without creating an order. The test setup should let the second shopper receive the scheduled text, so a quiet queue cannot make a broken test look successful.

For the paying shopper, record when the store made the order, when each platform showed the order event and whether it matched the profile waiting for the next message. Klaviyo documents checking its recommended placed-order profile filter before each message. Test the flow on your quote with that actual condition visible. In a split setup, find the corresponding purchase check in the SMS sender too.

If both shoppers are skipped, check whether they qualified for SMS, whether the flow was active and whether another rule stopped the send. If both receive the text, use the order, profile and stop checks above to find where the paid-order case went wrong. If only the shopper without an order receives it, repeat with a change that matters to your store, such as paying from a different device or using a different email at checkout.

A send that leaves before an order is visible is a different problem from a send that leaves after the condition should have been met. Keep the timestamps. The first points toward event timing or a longer delay. The second points toward the profile or the rule. A dashboard that credits the order to a message cannot settle either question.

Check the order event from every checkout path

A single test order can give you the wrong answer about a split recovery setup. Take a Shopify store that sells through its regular checkout and also accepts Buy with Prime orders. The Klaviyo recovery documentation names a separate Buy with Prime order event. A test that only uses the ordinary Shopify checkout never exercises that second event.

Run one test purchase through each checkout your store actually offers while the email and SMS reminders are queued. Record which event appeared on the profile, what rule used it and which message was canceled. Then test an incomplete checkout on the same path to verify the flow still sends to an eligible shopper.

Ask the vendor to show the equivalent evidence for each queue you plan to use. If a single platform can cover the same paths and your team can inspect them in one place, that reduces reconciliation. If you need a split setup for the SMS job, put an owner on each missing order event before moving that flow.

Read the provider documentation for the behavior described above.

Download the purchase test worksheet

Decide what happens to reminders already waiting

Ask the vendor to show a shopper who is already in the old journey when you switch. The new flow can work perfectly for a fresh checkout and still leave an old text due. Find out where those waiting recipients are listed and whether your operator can inspect or cancel a specific reminder.

Klaviyo's recovery guide describes how to cancel the next message for a specific recipient in Waiting or Needs Review. Use that as a concrete example of the screen your operator should be able to find. In the proposed Postscript configuration, ask for the corresponding account procedure and check it in the test rather than assuming the steps match.

Make a go-live list with the flow to disable, the flow to enable, the operator for each and a way to restore the old path. Choose a small test group that reflects your actual setup. Keep a record of which contacts were already waiting, which became eligible after the change and which sender handled them. A clean test on new contacts cannot answer for a queue that was already populated.

If an SMS needs a reply, add one support question before the pilot ends. Klaviyo's Customer Agent instructions call for an active SMS plan and a two-way sending number, with escalation determined by the configured handoff. Ask what handles the reply in the Postscript proposal as well. A successful outbound flow does not establish that somebody will see the answer.

Compare the whole month, including the email you keep

Bring the same month to both quotes. Use the count of active profiles, email sends, SMS and MMS, and a sample of real message lengths with personal details removed. Show the countries and number types you use. For a split program, keep the existing Klaviyo email cost in the estimate and price the Postscript scope on top of it.

Klaviyo's plan page prices plans against active profiles and lists email and mobile allowances. Postscript's pricing page shows messaging plans with SMS and MMS rates, carrier fees and charges that can vary with segments. A text that takes two billed segments is still one reminder in the workflow. Ask the vendor to price the actual messages you plan to send.

Keep setup work in a separate line. If SMS moves to a different owner, somebody still needs to check whether purchases appear in both tools, investigate unexpected sends, and update a flow when the store changes checkout. If you want shopper replies handled as well, ask for that scope on both quotes. Add the costs once you know what is included.

Choose the joined setup when it meets the send and reply requirements and the same team can operate it. Choose the split setup when it preserves working email and delivers a demonstrable reason to give SMS a separate owner. If the second platform cannot show a matched order before the next message is due, hold the switch until it can.