The four tools that decide your second purchase: email/SMS, reviews, loyalty, subscriptions. Here are the leaders, my pick at each stage, the suite trap that quietly doubles your bill, and dated pricing with the caveats that matter. All prices captured June 2026, verify before you sign.
Acquisition is rented. Retention is the part of the P&L you own. This is the stack that turns a first order into a repeat customer: the messaging layer (Klaviyo, Postscript), the proof layer (Okendo, Loox), the loyalty layer (Smile, LoyaltyLion), and the recurring-revenue layer (Recharge, Skio).
One framing before the tools. Every category here has a "suite" that wants to be all four at once. Yotpo will sell you reviews plus loyalty plus SMS. Attentive wants your email too. The suite pitch never changes: one vendor, one login, one invoice. Below nine figures I rarely see that math work, and I will show you why in each section. Best-of-breed point tools tend to beat the bundle on the individual job, and consolidating for its own sake is how you end up paying suite money for mediocre execution across four functions.
Pricing reality check, stated once. Every number below is vendor-published or widely-reported list pricing captured June 2026, and it drifts constantly. Retention tools are almost all usage-based. They bill on active profiles, messages sent, order volume, or a cut of subscription revenue, so your real bill depends on your volume, not the sticker. Treat every figure as "starting from" and verify on the vendor's page before you sign. Where a number is self-reported by the vendor I label it "vendor"; where it comes from a third-party aggregator I label it "reported"; verify either way.
The job: own the customer relationship off-platform and drive repeat revenue you do not pay Meta a second time to reach.
Email and SMS are where most of your owned revenue shows up, and also where the billing model bites hardest, because usage-based pricing on a growing list compounds. Watch what each tool bills on, not the entry price.
| Tool | Best for | Pricing (Jun 2026, verify) | My call |
|---|---|---|---|
| Klaviyo | The default DTC email platform; native AI segments, flows, predictive CLV | Free to 250 profiles / 500 sends. Email from $20/mo (500 contacts), ~$100/mo @ 5k, ~$150/mo @ 10k, ~$720/mo @ 50k. Email+SMS from $35/mo. SMS credits from $15/mo (1,250 credits; 1 credit/SMS, 3/MMS). Klaviyo One (enterprise) adds ~20% once monthly spend tops ~$10k. (vendor, klaviyo.com/pricing) | Our pick (email + the hub) |
| Postscript | Dedicated SMS for Shopify brands; transparent, low entry | From $0/mo + per-message: $0.015/SMS, $0.045/MMS on free, down to ~$0.007/SMS on Professional ($500/mo). (vendor/reported) | Our pick (SMS) |
| Attentive | Enterprise SMS + email + RCS + push for $20M+ multichannel | Quote-only; hybrid base + usage, quarterly minimums typically $2,000–$3,000+. (reported) | Enterprise |
| Omnisend | SMB that wants one cheaper email+SMS tool | Budget all-in-one email+SMS; entry tier low, scales by contacts (verify on vendor page). (reported) | Budget alt |
A few things the pricing page will not put in bold.
Klaviyo changed its billing to active profiles, not sends, in February 2025 (vendor). That matters more than it sounds. If you have a bloated list full of people who have not opened anything in a year, you are now paying to store them. The fix is unglamorous: suppress and sunset stale profiles on a schedule. A list cleanup is the highest-ROI hour you will spend in Klaviyo this quarter, because it lowers the bill and lifts deliverability at the same time.
The SMS billing model is the opposite trap. Postscript and the SMS side of Klaviyo bill per message, so the temptation is to blast. Don't. Consent quality and deliverability beat volume every time. A 5,000-person SMS list that opted in deliberately will out-earn a 40,000-person list scraped from checkout, and it costs you a fraction to send to.
Klaviyo has Segments AI and Flows AI built in, and there is an official Klaviyo connector for Claude. Here is the limit worth knowing: the connector is read-only for flows (vendor, verify, this is exactly the kind of thing that changes). Claude can read your flow logic, your segment definitions, your campaign performance. It cannot write a flow back into Klaviyo. Anyone selling you "Claude builds your flows automatically" is overstating it as of June 2026.
So what is the high-leverage build? Read-side analysis the native AI does not do well, because the native AI only sees Klaviyo data. Wire Claude into Klaviyo, Shopify, and Triple Whale or GA4, then ask it the questions that span all three:
You have read access to my Klaviyo, Shopify, and Triple Whale data.
1. Pull every active flow and its last-30-day revenue per recipient.
2. Cross-reference flow conversions against Shopify first-vs-repeat order data.
3. Find the flows where the email "win" is actually cannibalising orders
that would have happened anyway (people already in a buying session).
4. Rank flows by incremental revenue, not attributed revenue.
5. Flag any segment paying for storage with zero engagement in 120 days,
and estimate the monthly Klaviyo cost of suppressing them.
Output a table: flow, attributed rev, estimated incremental rev, action.
The distinction in step 4, attributed versus incremental revenue, is the one Klaviyo's own dashboard will never volunteer, because every platform reports the most flattering version of its own contribution. Claude reading across three sources will tell you which of your "top flows" are taking credit for purchases that were going to happen anyway. The usual suspect is the abandoned-cart flow, which loves to claim sales from people who came back on their own. When you find that, it is not a reason to kill the flow. It is a reason to stop sizing your retention team around a number that is half theatre.
The build is connectors you already have access to plus one prompt. It replaces nothing you pay for. It makes the read layer honest.
Running Klaviyo for email and a separate tool for email. Consolidate the email function into one platform. The exception is SMS. Klaviyo's SMS is fine, but Postscript's per-message economics and Shopify-native flows are usually better below enterprise, and splitting email (Klaviyo) from SMS (Postscript) is one of the few "two tools" setups I will defend, because each is best at its own job and they integrate cleanly. The other thing to ignore: buying SMS volume ahead of demand. You do not need 50k credits a month. You need a clean opted-in list.