sms

---
name: sms
description: Use when planning, building, or optimizing SMS/MMS marketing — welcome flows, abandoned cart, post-purchase, win-back, promotional or transactional texts, or compliance (TCPA, A2P 10DLC, CASL).
category: Marketing
version: 1.0.0
tools: []
---

# SMS Marketing

Plan, build, and optimize SMS and MMS programs for direct-to-consumer brands, mobile apps, and SaaS with high-engagement use cases — driving measurable revenue or activation while staying fully compliant with TCPA and carrier rules.

## Before Starting

Search the Knowledge Base for existing product-marketing context before asking questions; only ask for what's missing.

Gather: **business type** — B2C ecom/DTC, B2B SaaS, mobile app, services, fintech; order volume or list size (SMS economics depend on scale); geographic mix (US, EU, both — compliance differs dramatically). **Current state** — existing SMS program (platform, list size, opt-in rate, opt-out rate, revenue/send), email program (SMS works best as a layer on top, not a replacement), phone number type (short code, toll-free, long code/10DLC). **Compliance posture** — US A2P 10DLC registration status (required since 2022; without it, messages get filtered), opt-in mechanism in use (checkbox, keyword, double opt-in), whether privacy policy and terms include SMS disclosures. **Goal** — drive revenue (promotional, cart recovery, post-purchase), drive activation (welcome, onboarding, milestones), or transactional (order updates, auth codes, alerts).

## When SMS Beats Email

| Use case | Channel | Why |
|---|---|---|
| Abandoned cart recovery | SMS first | 98% open rate within 3 min vs. 20% for email in 24h |
| Order/shipping updates | SMS | Customers want it now, on their phone |
| Flash sale / limited drop | SMS | Urgency channel, immediate read |
| Auth codes / 2FA | SMS (or app) | Latency-sensitive, must arrive in seconds |
| Welcome series | Email primary, SMS layer | Email carries the long-form content |
| Educational nurture | Email | Too much text for SMS, costs add up |
| Newsletter | Email | Wrong channel for SMS |
| Win-back lapsed customers | Both | SMS for the nudge, email for the offer detail |
| Post-purchase upsell | SMS | High open rate, rides the purchase momentum |

General rule: SMS earns the right to interrupt because of opt-in — use it only for messages that genuinely benefit from immediacy. If it could wait 24 hours, use email.

## Compliance — Read First

Compliance is the foundation, not an afterthought — a single TCPA class-action settlement runs $5M–$40M.

**US — TCPA.** Express written consent required for marketing SMS (implied consent doesn't count). Clear disclosure at opt-in: program name, frequency expectation ("up to 4 msgs/month"), STOP/HELP instructions, "Msg & data rates may apply," link to terms. Honor STOP/UNSUBSCRIBE within seconds, every time, on every keyword variant (STOP, END, CANCEL, UNSUBSCRIBE, QUIT). Honor HELP with brand name + STOP info + support contact. Quiet hours: no marketing sends before 8am or after 9pm recipient-local; several states (Florida, Oklahoma, Washington) are stricter than federal — default to 9am–8pm recipient-local. Keep written consent records with timestamp, opt-in source, and exact disclosure text shown — auditable.

**US — A2P 10DLC registration**, required since 2022, via The Campaign Registry (TCR) through the SMS platform. Without it: throughput is throttled or zero, carriers filter messages, and "delivered" status shows while recipients get nothing. Registration covers brand identity verification, campaign use case, sample messages, opt-in mechanism, opt-out language — the sample text on file must match what's actually sent.

**EU/UK — GDPR-derived consent:** explicit opt-in required (no pre-checked boxes), withdrawal must be as easy as opting in, DSARs apply to SMS records, ePrivacy Directive layered on top.

**Canada — CASL:** express consent + sender identification + unsubscribe in every message; implied consent allowed for existing business relationships within 24 months; penalties up to CAD $10M per violation.

## Phone Number Types (US)

| Type | Throughput | Cost | Use case | Trust |
|---|---|---|---|---|
| Short code (5–6 digit) | 100+ msg/sec | $500–$1,000/mo + setup | High-volume marketing | Highest (carrier-vetted) |
| Toll-free (1-8XX) | ~3 msg/sec | $10–$30/mo | Mid-volume, B2C support | Medium-high |
| 10DLC (regular long code) | 1–250 msg/sec | $2–$10/mo | SMB, conversational, transactional | Medium (requires A2P reg) |

Rule of thumb: list <10K → 10DLC; 10K–100K → toll-free; 100K+ → short code.

## Core Principles

Every send has a real cost — at $0.0075–$0.04 per send plus carrier fees, a 100K send costs $750–$4,000, which forces relevance; segment hard. Opt-in is the most valuable asset — opt-in rate from email to SMS is typically 5–25%; a high-quality 10K list beats a low-quality 100K list. Every message must justify itself: "would the recipient be glad they got this text?" — if no, don't send. Brevity matters: 160 GSM-7 characters = 1 segment; 161+ chars = 2 segments (billed for 2); emojis force UCS-2 encoding (70 chars/segment). One CTA, one short link, with UTM params tracked on every link. Sender identity on every send — "From [Brand]:" inline, since recipients can't see a "from" address on SMS.

## SMS Sequence Types

**Welcome/opt-in confirmation** (immediate) — confirmation + reward, e.g. "Thanks for joining! Here's 10% off: ACME10." Optional Send 2 at 24h: reminder + best-seller showcase.
**Abandoned cart** (highest-ROI ecom flow) — Send 1 at 30 min ("Forget something?"), Send 2 at 4 hours (soft urgency + social proof), Send 3 at 24 hours (discount, if margin allows). Discounting the first message trains customers to abandon — reserve it for Send 2 or 3.
**Browse abandonment** — Send 1 at 1 hour: product + "Thinking it over?" + link.
**Post-purchase** — Send 1 immediate: order confirmation + delivery ETA (transactional, separate consent OK). Send 2 after delivery + 2 days: satisfaction check + review prompt + cross-sell.
**Win-back** — Send 1 at 60–90 days: "we miss you" + curated picks. Send 2 at +14 days: discount offer. Send 3 at +14 days: opt-out warning + last chance.
**Promotional/campaign** — flash sales, drops, launches, BFCM; 1–2 sends max per campaign; stack against the email schedule to avoid same-day double-tap.
**Transactional** — order updates, shipping, delivery, auth codes, account alerts; generally OK without separate marketing consent when directly tied to a user-initiated transaction, but still subject to A2P 10DLC registration in the US.

## SMS Copy Guidelines

Structure: sender ID (required) → hook (first 5 words decide if they read on) → value (what's in it for them, specifically) → CTA + single short link → compliance footer ("Reply STOP to opt out," required on opt-in confirmation and at least quarterly, carrier-recommended on every promotional message).

Length: 160 chars (GSM-7) = 1 segment, aim here; 70 chars (UCS-2) if using emojis/accents/curly quotes; 161–306 chars = 2 concatenated segments (paying double); MMS (image + up to 1,600 chars) costs 3–5× SMS — use sparingly for high-impact moments.

Voice: conversational, not corporate — write like texting a friend; no subject line, no marketing-speak; emojis fine in moderation (one per message); ALL CAPS reads as shouting, reserve for explicit codes.

Personalization: first-name token where available boosts CTR ~20%; recent browse/category-based; location-based where applicable; don't fake intimacy ("Hey friend!") — it backfires.

## Platform Selection

Klaviyo SMS for DTC ecom already on Klaviyo email; Postscript for Shopify ecom wanting deep SMS-specific features; Attentive for mid-market+ full-service ecom; Twilio for custom builds, transactional, and developer-driven products; Brevo SMS for EU-focused email+SMS combos; SimpleTexting for SMB simplicity; Customer.io for behavior-based automation plus SMS. B2B SaaS doing transactional/auth typically wants Twilio or Customer.io.

## Measurement

| Metric | Tells you | Healthy range (ecom DTC) |
|---|---|---|
| Opt-in rate | Top-of-funnel health | 5–25% of email subscribers |
| CTR | Message relevance | 8–15% (vs. ~3% email) |
| Conversion rate per send | Revenue impact | 1–5% per promotional send |
| Revenue per send (RPS) | Channel economics | $0.20–$2.00 |
| Opt-out rate per send | Audience fatigue | <2% per send, <0.5% promotional |
| Cost per send | Channel cost discipline | $0.0075–$0.04 |
| List growth rate | Audience momentum | 5–15%/month early, 1–3% steady-state |

Track: UTM-tag every link (`utm_source=sms&utm_medium=sms&utm_campaign=[name]`); attribution via SMS-driven sessions, last-click revenue, assisted conversions; LTV impact (SMS subscribers typically run 1.5–3× the LTV of email-only subscribers). A/B test send time, copy length (SMS vs. MMS with image), discount amount/trigger timing, personalization tokens, and CTA copy.

## Output Format

For an SMS plan, return: compliance check (A2P 10DLC status if US, opt-in mechanism compliance — flag blockers first); strategy (which flows to build first, ranked by ROI); sequence designs (trigger, delay, copy with character counts, CTA, segmentation per priority flow); platform recommendation (based on stack, list size, complexity); measurement plan (KPIs, benchmarks, A/B test queue); compliance footer (required disclosures, STOP/HELP templates). Be specific — "send 30 min after cart abandon, 4 hours later if no purchase, 24 hours later with discount," not "send at the right time."

## Task-Specific Questions

1. US, EU, or both?
2. Is A2P 10DLC registration complete (US)?
3. What platform is in use or under consideration?
4. Email list size and current SMS opt-in rate?
5. What sequences are already running?
6. DTC ecom, mobile app, B2B SaaS, or services?
7. Primary goal: revenue, activation, retention, or transactional?

## Common Mistakes

Skipping A2P 10DLC registration (messages get filtered — register first, send second); treating SMS like email with daily promotional blasts (opt-out rates spike, list dies); discounting the first abandoned-cart message (trains customers to always abandon); generic sender identification with no brand name inline; ignoring quiet hours (6am local sends drive opt-outs and TCPA complaints); missing STOP/HELP handling (non-negotiable — verify the platform handles it); emoji-heavy copy that forces UCS-2 encoding and doubles segment cost.