# What's the real support-response time for Postscript compared to Klaviyo when an SMS campaign breaks mid-send?

Reviewed by Martin Dejnicki, Director of SEO & AI Search · facts verified October 11, 2026 · canonical: https://deploi.ca/shopify/faq/postscript-vs-klaviyo-support-response-time

## Short answer

Postscript publishes the faster support target: priority live chat replies in under 5 minutes on Professional and under 2 on Enterprise, on weekdays ([Postscript's support page](https://postscript.io/customer-service), October 2026). Klaviyo's standard support targets 4 business hours for urgent email ([Klaviyo's support packages](https://www.klaviyo.com/success/premium-support), October 2026). Neither is a measured time for a broken SMS (text message) send, so treat both as promises.

- **Postscript priority live chat:** Under 5 minutes, or under 2 on Enterprise. Targets for the Professional and Enterprise plans; live chat runs Monday to Friday, 6am to 5pm Pacific (9am to 8pm Eastern), and email goes to support@postscript.io (October 2026) ([Postscript, Customer Service](https://postscript.io/customer-service))
- **Klaviyo urgent email response:** 4 hours standard, 1 hour on Enterprise. Standard support comes with paid plans; the premium Professional (2 hours) and Enterprise (1 hour) packages are faster, all counted in local business hours (October 2026) ([Klaviyo, Klaviyo Premium Support & Customer Success Packages](https://www.klaviyo.com/success/premium-support))
- **Weekend and peak coverage:** Published by Klaviyo, not by Postscript. Klaviyo: weekend chat varies by package, 24/7 on Enterprise, and 24/7 email and chat for paid plans from Thanksgiving through Cyber Monday. Postscript lists weekday chat hours only (October 2026) ([Klaviyo, Klaviyo Premium Support & Customer Success Packages](https://www.klaviyo.com/success/premium-support); [Klaviyo Help Center, How to contact support](https://help.klaviyo.com/hc/en-us/articles/115001002272); [Postscript, Customer Service](https://postscript.io/customer-service))
- **Shopify's certification floor:** 30-minute first response to critical issues. Both vendors are Certified Technology Partners, so both owe Shopify this and 24/7 support worldwide; it binds them to Shopify, not to you (October 2026) ([Shopify Help Center, How to qualify as a Certified Technology Partner](https://help.shopify.com/en/partners/partner-program/how-to-qualify); [Shopify, Shopify Certified Technology Partner Program](https://www.shopify.com/partners/blog/shopify-plus-apps))

## Deploi's call

Postscript publishes the faster support target and Klaviyo the wider coverage. Neither publishes a measured response time for a send that breaks mid-flight, and we will not estimate one, because an invented figure would be used as a benchmark. Support responsiveness is still a weak selection criterion for SMS (text message), because the common failure modes are carrier-side or self-inflicted and neither is resolved by a faster first reply.

**BUY: Postscript's support fits when**

- Your SMS (text message) sends go out on weekdays between 9am and 8pm Eastern, inside Postscript's live chat hours ([Postscript](https://postscript.io/customer-service), October 2026).
- You are on Postscript's Professional or Enterprise plan, where priority chat targets under 5 or under 2 minutes ([Postscript](https://postscript.io/customer-service), October 2026).
- SMS has its own owner and revenue target, where Deploi's Klaviyo vs. Postscript record moves SMS to Postscript ([Deploi Build vs. Buy](https://deploi.ca/shopify/build-vs-buy/klaviyo-vs-postscript), October 2026).

**BUY: Klaviyo's support fits when**

- Your sends run overnight or on weekends: Klaviyo's chat runs around the clock on weekdays, and its Enterprise support package adds 24/7 weekends ([Klaviyo](https://www.klaviyo.com/success/premium-support), October 2026).
- Your biggest sends fall between Thanksgiving and Cyber Monday, when Klaviyo staffs email and live chat 24/7 for paid plans ([Klaviyo Help Center](https://help.klaviyo.com/hc/en-us/articles/115001002272), October 2026).
- Email leads and SMS supports it, where the same record keeps SMS inside Klaviyo ([Deploi Build vs. Buy](https://deploi.ca/shopify/build-vs-buy/klaviyo-vs-postscript), October 2026).

## How fast do Postscript and Klaviyo support respond when an SMS send breaks?

Postscript's published support target is a first reply in minutes; Klaviyo's published targets are in hours. Postscript promises "Priority live chat support" in under 5 minutes on its Professional plan and under 2 on Enterprise ([Postscript](https://postscript.io/customer-service), October 2026). Klaviyo publishes email targets by support package, counted in local business hours ([Klaviyo](https://www.klaviyo.com/success/premium-support), October 2026). Neither is a measured response time for an SMS (text message) send that breaks mid-flight, so read both as promises. This answer drills into the support side of [the Postscript and Attentive choice for two-way texting](https://deploi.ca/shopify/faq/postscript-vs-attentive-two-way-conversational-sms).

**Postscript publishes chat targets in minutes on two plans; Klaviyo publishes urgent email targets in hours by support package**

| Support level | Published first-response target | Live chat coverage |
| --- | --- | --- |
| Postscript Growth plan | None published | Weekdays, 6am to 5pm Pacific |
| Postscript Professional plan | Chat under 5 minutes | Weekdays, 6am to 5pm Pacific |
| Postscript Enterprise plan | Chat under 2 minutes | Weekdays, 6am to 5pm Pacific |
| Klaviyo Standard, in paid plans | Urgent email 4 hours | 24/5, no weekend coverage |
| Klaviyo Professional package | Urgent email 2 hours | 24/5, local business hours at weekends |
| Klaviyo Enterprise package | Urgent email 1 hour | 24/7 |

Sources: [Postscript, Customer Service](https://postscript.io/customer-service); [Klaviyo, Klaviyo Premium Support & Customer Success Packages](https://www.klaviyo.com/success/premium-support); [Postscript, Pricing](https://postscript.io/pricing). Verified October 9, 2026.

## Who answers Postscript and Klaviyo support on weekends and over Black Friday?

Klaviyo's support answers on weekends and over Black Friday, depending on the package, while Postscript publishes weekday live chat only. Postscript's live chat runs Monday to Friday, 6am to 5pm Pacific (9am to 8pm Eastern), and email goes to support@postscript.io ([Postscript](https://postscript.io/customer-service), October 2026). Shopper, Postscript's conversational AI, "works 24/7", but it answers your subscribers, not your team ([Postscript's Shopper page](https://postscript.io/shopper), October 2026).

Klaviyo offers 24/7 email on paid plans and chat "24/5, weekend hours vary by plan". It is moving chat into Composer, its in-app assistant, which tries to answer first and "may offer the option to chat with a human" ([Klaviyo Help Center](https://help.klaviyo.com/hc/en-us/articles/115001002272), October 2026). From Thanksgiving through Cyber Monday, Klaviyo staffs email and live chat 24/7 for all paid plans. [Shopify's Certified Technology Partner criteria](https://deploi.ca/shopify/faq/postscript-shopify-plus-certified-partner) require "24/7 support available worldwide" by phone, chat or email ([Shopify Help Center](https://help.shopify.com/en/partners/partner-program/how-to-qualify), October 2026). So ask Postscript which route reaches a person on a Saturday night.

## Which mid-send failures can SMS support actually fix?

Support can fix few SMS (text message) failures mid-send, because most causes sit with carriers or with your own setup. In Deploi's judgment, four causes cover most broken sends:

- **Carrier filtering.** The platform accepts messages and a carrier drops them. Postscript says a short code gets "faster resolution for erroneous carrier filtering", and a toll-free number "Slower resolution times with carriers" ([Postscript Help Center](https://help.postscript.io/en/articles/13563949-comparing-short-code-and-toll-free-numbers), October 2026). Postscript also cites "8+ years of carrier relations" and real-time visibility into carrier queues ([Postscript's deliverability page](https://postscript.io/deliverability), October 2026).
- **Toll-free throughput.** A big send on a toll-free number queues and lands late, because Postscript's short codes are "7x faster for SMS messages" on average ([Postscript's comparison article](https://help.postscript.io/en/articles/13563949-comparing-short-code-and-toll-free-numbers), October 2026). That choice was made weeks earlier.
- **Segment or link errors.** These are your configuration: support can help you stop the send, not unsend it.
- **A platform incident.** The rarest case, and the only one Shopify's 30-minute criterion covers, when an outage hits several customers ([Shopify's criteria page](https://help.shopify.com/en/partners/partner-program/how-to-qualify), October 2026).

## How do you stop an SMS campaign that is already sending?

You stop an SMS (text message) campaign that is already sending from inside the platform, and both Postscript and Klaviyo warn the stop is partial. In Postscript, a campaign flow stops from Flow Builder: select End campaign, then Stop campaign. Postscript says "there may be messages that still go out afterward", and a stopped campaign flow can't be re-activated ([Postscript Help Center](https://help.postscript.io/en/articles/13563955-create-a-campaign-flow), October 2026). Postscript documents that stop for campaign flows only: its Basic Campaign guide gives no way to stop a launched campaign ([Postscript's campaign guide](https://help.postscript.io/en/articles/15697159-create-a-basic-campaign), October 2026). In Klaviyo, cancel from the Campaigns tab, and the status turns to "Cancelled During Send". Klaviyo "cannot roll back (i.e., unsend) messages that have already been delivered" ([Klaviyo Help Center](https://help.klaviyo.com/hc/en-us/articles/115005085067), October 2026).

So the fastest response to a broken send is your own. Name the people who can press stop on each platform, and rehearse it before you need them. A vendor that replies in five minutes still leaves five minutes of a send you could have stopped in one.

## How can you measure Postscript and Klaviyo support before you need it?

Measure Postscript and Klaviyo support during the trial, because a published target is a promise, not a record. It takes about a week:

1. **Open a real low-priority ticket with each vendor** at an awkward hour, and log the time to the first human reply. That is one data point each, so label it as one.
1. **Ask each vendor for its status page** and read the last twelve months of incidents; Shopify's criteria require a certified partner to provide one ([Shopify's criteria page](https://help.shopify.com/en/partners/partner-program/how-to-qualify), October 2026).
1. **Put the critical-incident first-response target in the order form,** because certification binds the vendor to Shopify, not to you.
1. **Ask two references at your send volume** what happened the last time a send went wrong, and how they found out.
1. **Rehearse the stop.** Time how long your own team takes to end a test campaign on each platform.

## When should support response not decide the SMS vendor?

Support response should not decide the SMS (text message) vendor when your send times, your team or your incident history point elsewhere.

> **When not to do this**
> - **When you send in US office hours.** Both vendors' published live chat covers a weekday afternoon send ([Postscript](https://postscript.io/customer-service); [Klaviyo Help Center](https://help.klaviyo.com/hc/en-us/articles/115001002272), October 2026).
> - **When nobody on your side watches the first ten minutes of a send.** A vendor's response time can't beat an unwatched dashboard.
> - **When the last three incidents were content or segmentation errors.** Fix the pre-send checklist instead of shopping for a faster desk, because Postscript campaigns "cannot be edited after launch" ([Postscript's campaign guide](https://help.postscript.io/en/articles/15697159-create-a-basic-campaign), October 2026).

## Deploi's point of view

**Where we disagree.** Vendor comparisons rank support quality from review sentiment, which measures onboarding experience far more than incident handling, because onboarding is when most people write reviews. We would rather hand you five things to test than a star rating that is answering a different question.

**Our judgment, not a measurement.** In post-incident reviews the recoverable minutes are almost always on the merchant's side of the line, in detection and in who is allowed to hit pause. The ticket timestamp is rarely the binding constraint.

**What this page adds.** The parent compares Postscript and Attentive on who staffs replies; this page sets Postscript's and Klaviyo's published support targets and hours side by side as of October 2026, shows who covers weekends and Black Friday, which mid-send failures support can fix, and how each platform stops a send already in flight.

## When this answer changes

- Postscript changes its priority chat targets, under 5 minutes on Professional and under 2 on Enterprise, or its weekday hours.
- Klaviyo changes its email response targets by support package, or its weekend and Black Friday coverage.
- Klaviyo finishes moving chat support into Composer, or changes when Composer hands a chat to a person.
- Shopify changes its 30-minute critical response or 24/7 support criteria for Certified Technology Partners.
- Postscript or Klaviyo changes how a campaign stops once it is sending.
- Deploi re-scores its Klaviyo vs. Postscript record.

## Sources

1. [Postscript, Customer Service](https://postscript.io/customer-service), checked October 9, 2026
2. [Klaviyo, Klaviyo Premium Support & Customer Success Packages](https://www.klaviyo.com/success/premium-support), checked October 9, 2026
3. [Postscript, Pricing](https://postscript.io/pricing), checked October 9, 2026
4. [Klaviyo Help Center, How to contact support](https://help.klaviyo.com/hc/en-us/articles/115001002272), checked October 9, 2026
5. [Shopify Help Center, How to qualify as a Certified Technology Partner](https://help.shopify.com/en/partners/partner-program/how-to-qualify), checked October 9, 2026
6. [Postscript, Shopper: Agentic 1:1 Marketing is here](https://postscript.io/shopper), checked October 9, 2026
7. [Postscript Help Center, Comparing Short Code and Toll-Free Numbers](https://help.postscript.io/en/articles/13563949-comparing-short-code-and-toll-free-numbers), checked October 9, 2026
8. [Postscript, Deliverability](https://postscript.io/deliverability), checked October 9, 2026
9. [Postscript Help Center, Create a Campaign Flow](https://help.postscript.io/en/articles/13563955-create-a-campaign-flow), checked October 9, 2026
10. [Klaviyo Help Center, How to cancel a scheduled or sending campaign](https://help.klaviyo.com/hc/en-us/articles/115005085067), checked October 9, 2026
11. [Postscript Help Center, Create a Basic Campaign](https://help.postscript.io/en/articles/15697159-create-a-basic-campaign), checked October 11, 2026
12. [Shopify, Shopify Certified Technology Partner Program](https://www.shopify.com/partners/blog/shopify-plus-apps), checked October 11, 2026
13. [Deploi Build vs. Buy, Klaviyo vs. Postscript: Email-First or SMS-First on Shopify?](https://deploi.ca/shopify/build-vs-buy/klaviyo-vs-postscript), checked October 9, 2026, Deploi research