Building an SMS Opt-In List from Square Customers

Start from real customers

Prioritize people who already bought and shared a phone in a legitimate relationship with your business. Do not buy cold SMS lists. A smaller warm list will outperform a huge hostile one on both ROI and deliverability.

Make joining obvious

Use a simple join page, counter signage, and staff scripts: what they get, how often, and how to stop. Clarity beats fine print. Guests should never be surprised by the first marketing text.

• One-line value prop on the counter
• Join page with brand voice + STOP expectation
• Staff trained to accept “no” gracefully

Honor STOP like a product feature

Every message should make opt-out easy. Process STOP immediately. High opt-out rates are a copy and frequency problem — fix them fast rather than blaming “people who hate texts.”

Quality over raw count

Audit new numbers weekly for typos and junk. Suppress serial complainers. Celebrate engaged regulars, not list size vanity on a franchise dashboard.

How ReturnFlowHQ helps

Join flows, STOP handling at the webhook layer, send windows, and cooldowns are built so operators can grow lists without inventing compliance plumbing — then personalize from Square history.

Common mistakes to avoid

Buying cold phone lists, blasting the same coupon to everyone, skipping STOP language, and measuring only “messages sent” instead of return visits. Fix those before you scale volume. A smaller clean list with attributed tickets will beat a huge hostile list every quarter.

• No purchased SMS lists
• Segment by visit cadence and relevance
• Track attributed visits, not vanity sends
• Exclude same-day visitors from marketing batches