LTV to CAC Ratio: How to Calculate It for Ecommerce

An SMS marketing agency runs the full text channel for a brand: compliant consent capture, list growth, automated flows, campaign strategy, platform management, and revenue reporting. The work divides into five functions — and the first one is the reason most brands should not run SMS casually.

1. Compliance and consent architecture. SMS is a regulated channel. TCPA consent capture, required disclosures, quiet hours, and opt-out handling are legal exposure when done wrong, not just bad practice — and the exposure attaches to the brand, not the platform. An agency’s first deliverable is a consent map: where every subscriber came from, exactly what they agreed to, and proof of it, with imported lists quarantined until their consent quality is verified. Unglamorous, and worth more than any campaign idea.
2. List growth. Popups, keyword opt-ins, and checkout collection tuned to convert traffic you already have — with incentives priced against margin rather than copied from a swipe file. Program design dominates the tooling: when we launched SMS for Darc Sport, the list reached 41,000 subscribers within two months, driven by drop-day mechanics and offer design as much as any widget. The platform sets the ceiling; the mechanics decide where under it you land.
3. Automated flows. Cart abandonment, browse, back-in-stock, post-purchase, winback — built, then iterated monthly against results. This is where SMS earns its keep: Postscript’s 2026 benchmarks put abandoned-cart texts at 9.5%–17.3% click-through for the middle half of stores, earning $3.52–$10.95 per message, and Omnisend’s data shows automated texts converting at six times campaign rates. An agency that leads its pitch with campaign ideas rather than flow architecture has the channel backwards.
4. Campaign strategy — including restraint. Every send has a per-message cost and a goodwill cost, which makes SMS the one owned channel where discipline is a core deliverable. Good agencies run fewer, sharper campaigns segmented to buyers who want them, treat the opt-out rate as a managed KPI rather than a surprise, and time sends around quiet hours and time zones automatically.
5. Platform management and reporting. Choosing and operating the stack — the Attentive vs Postscript decision has real economic consequences at volume — plus deduplicated attribution so SMS revenue is not double-counted against email, holdout checks where incrementality is in doubt, and a monthly report that reconciles to store revenue.

Agency vs in-house. In-house works when SMS is small and someone already owns email deeply — the channels share segmentation logic, and one operator can run both at modest volume. The agency case strengthens as volume grows: compliance stakes rise, flow architecture deepens, and orchestration with email becomes the genuinely hard part. SMS rarely performs in isolation either; it earns most inside a full retention program, which is why it is one of six channels the top retention agencies run together rather than a standalone line item.

What the first quarter of an engagement looks like. Month one: the audit and consent map, platform configuration, and the core flow builds — cart, browse, back-in-stock, post-purchase — because automation carries the economics. Month two: campaign cadence begins against segments rather than the full list, keyword and popup acquisition gets tuned, and the first optimization pass hits the flows. Month three: the first honest performance read — automated-versus-campaign revenue split, list growth against opt-out rate, revenue reconciled to store totals — and a quarter-two roadmap ranked by yield. Pricing follows scope: standalone SMS management typically starts around $1,500–$4,000 monthly depending on volume, while brands running email and SMS with one partner usually fold it into a combined retention retainer — the orchestration advantage is most of the argument for bundling.

Three questions that sort SMS agencies fast. Ask for a flow-versus-campaign revenue split from a live account; ask who owns compliance and what their consent-map process is; ask how they report incrementality, not just attribution. Specific answers mean an operator; adjectives mean a reseller.

What it looks like done properly: consent-clean growth, automation carrying the revenue load, campaigns that respect the channel, and reporting you can reconcile. That is the standing scope of our SMS marketing service — and the standard to hold any agency to, ours included.