Postscript vs Attentive: which one is the right SMS platform once a Shopify brand needs two-way conversational texting?

Who writes the replies when Postscript or Attentive runs two-way texting?

Your own team writes the escalated replies on Postscript, while Attentive sells live agents to write them. Two-way SMS (text message) is an inbox with a service level, so this vendor choice is mostly a staffing choice. Every Postscript plan includes "Response management (reply to texts from subscribers)" (Postscript's pricing, October 2026), and both vendors now put AI in front of the inbox:

Headline claims don't separate them: Postscript cites a 15x median incremental return on ad spend (iROAS) and Attentive more than 15 times return on investment (ROI), neither with a sample or a date (Postscript and Attentive, October 2026). If nobody on your side will answer a thread that goes sideways on a Saturday, buy the staffing. How fast Postscript's and Klaviyo's support teams answer when a send breaks is a separate question.

Should a two-way SMS program send from a short code or a toll-free number?

A short code (a 5 or 6-digit number) suits high-volume sending and a toll-free number (10 digits) suits a fast launch, because the number type sets approval time, throughput and cost before the vendor does. Postscript documents both for SMS (text message) and MMS (picture message):

A mid-October short code application lands after Black Friday (27 November 2026) at about 14 weeks and could at 4 to 7, while a toll-free number can be verified in time (Postscript Help Center and its short code timeline, October 2026). Throughput is what breaks in production: Postscript warns that a large send in a short period can overflow the message queue (Postscript's throughput guide, October 2026). Postscript's full onboarding timeline sets out every approval queue.

What do US opt-out rules require of a two-way inbox?

US opt-out rules require a staffed two-way inbox, because customers revoke consent in their own words and every revocation runs on a deadline. The Code of Federal Regulations (CFR) sets that deadline. A reply of "stop," "quit," "end," "revoke," "opt out," "cancel," or "unsubscribe" revokes consent outright. Any other reply counts if "a reasonable person would understand those words to have conveyed a request to revoke consent." Every revocation must be honored within "a reasonable time not to exceed ten business days from receipt of such request", and senders "may not designate an exclusive means to request revocation of consent" (47 CFR 64.1200, October 2026). So opt-outs arrive as free text, which is why Postscript lists "fuzzy opt-outs" and automatic removal of subscribers who change carriers among its compliance tools (Postscript's compliance guide, October 2026).

This describes an operational workload, not legal advice. Have counsel review your opt-in language and record-keeping before you scale a two-way program.

What do Postscript and Attentive publish about price?

Postscript publishes its SMS (text message) rates, and Attentive publishes no SMS plan or per-message prices. So only Postscript's SMS cost can be modeled before a sales call. Postscript charges $0.007 to $0.009 per SMS plus carrier fees, which average $0.00330 per US SMS (Postscript pricing, October 2026). Those listed rates cover the 50 US states and Canada. Starter is $0 a month with a $49 monthly minimum spend, Growth $100, Professional $500 and Enterprise quoted. Shopper, Postscript's conversational AI, sits in the Postscript AI Plan at $699 a month plus per-message rates of $0.003 to $0.30.

Attentive's App Store listing offers a "Minimum 30-day free trial" and says "Additional charges may apply" (Shopify App Store, October 2026). Its pricing page says pricing "is tailored to your business needs" (Attentive pricing, October 2026). The one SMS fee Attentive prints is the short code: $750 a month for a non-vanity code and $1,250 for a vanity one (Attentive Help Center, October 2026).

That difference is about your calendar, not value. If your approval process needs a figure in a deck before anyone takes a meeting, the price asymmetry decides more than the feature comparison does.

Where is Postscript or Attentive the right SMS platform?

Postscript is the right SMS (text message) platform when your own team will run the inbox, and Attentive is right when you want to buy the staffing.

• Postscript fits when Shopify is the storefront, your support team will own escalations and you want to model cost before you commit. Why a Shopify-only stack favors Postscript tests that case.
• Postscript with Postscript Plus fits when you want self-serve rates but nobody to run the program. You are buying strategists; ask what Plus's listed "Conversational Support for brands using Shopper" covers before you count on it for replies.
• Attentive fits when SMS is the primary owned channel, volume justifies a negotiated rate and you want live agents covering the inbox around the clock.
• Neither vendor fits yet when nobody has sized the channel.

Certification doesn't settle it: Shopify lists both vendors under "Messaging and notifications" among its Certified Technology Partners (Shopify, October 2026), so the badge works as a vetting floor. If a second ecommerce platform is coming, weigh Postscript's Shopify focus against Klaviyo's platform breadth.

When should a brand hold off on the Postscript and Attentive decision?

Hold off on the Postscript and Attentive decision when the number type, the inbox owner or the consent records are unsettled, because each one decides more than the vendor does.