Softwr

Marketing · head to head

Postscript vs Selenium

Postscript logo

Postscript

Marketing

SMS marketing built for Shopify merchants, with carrier fees billed on top of message rates

From
$49/month
Rated
-
Full reviewWebsite
Selenium logo

Selenium

Testing

Browser automation framework and the W3C WebDriver standard

From
Free
Rated
-
Full reviewWebsite

The short version

  • Only Selenium has a free tier, so it costs nothing to try first.
  • Each has a real cost: Postscript carrier pass-through fees are billed on top of the per-message rate, roughly $0.00418 per SMS and $0.00841 per MMS in the United States, and are routinely missing from the cost comparisons buyers build.; Selenium flaky tests are the standing complaint: explicit waits and synchronisation are the tester’s job, where newer tools handle it automatically
  • They diverge on capability: Postscript covers Shopify segmentation, Selenium covers W3C WebDriver.
  • Prices and features above were last checked on 31 August 2026.

Where they differ

Only the attributes on which Postscript and Selenium actually diverge.

Attributes where Postscript and Selenium differ
AttributePostscriptSelenium
Starting price$49/monthFree
Pricing modelPer month plus per message sentOpen source, no licence fee
Free tierNoYes
PlatformsWeb, iOSLinux, macOS, Windows, Web
CategoryMarketingTesting

Identical on both: user rating (Not yet rated).

What each one covers

Drawn from each product's published feature list. An absence here means we hold no record of it - not that the product lacks it.

Only in Postscript

  • Shopify segmentation
  • Automated flows
  • Subscriber acquisition
  • Two-way conversations
  • MMS campaigns
  • Revenue attribution
  • Headless SDK
  • Usage-based tiers

Only in Selenium

  • W3C WebDriver
  • Many language bindings
  • Selenium Grid
  • Broad browser support

What people use each for

The jobs each tool is most often brought in to do.

Postscript

  • A Shopify direct-to-consumer brand that wants abandoned cart recovery by text rather than another email in an ignored inboxnot Selenium
  • A brand running a product drop where a timed broadcast to an opted-in list is the whole launch mechanismnot Selenium
  • A merchant segmenting by past purchase and variant to send replenishment reminders at the right intervalnot Selenium
  • A store on headless Shopify or a custom stack that still wants SMS built on order data through the SDKnot Selenium

Selenium

  • Cross-browser testing where Safari and legacy browsers must be coverednot Postscript
  • Teams whose test suites are written in Java or C# rather than JavaScriptnot Postscript
  • Distributing a large suite across a grid of machinesnot Postscript

Where each one falls short

Documented limitations, not opinions. Every one is a constraint you would hit in normal use.

Postscript

  • Carrier pass-through fees are billed on top of the per-message rate, roughly $0.00418 per SMS and $0.00841 per MMS in the United States, and are routinely missing from the cost comparisons buyers build.
  • The cheapest per-message rates require the $500 a month plan, so a small sender pays more than double the headline low rate per text.
  • The $0 Starter plan carries a $49 minimum monthly spend, so it is not a free tier and quiet months still generate a bill.
  • US SMS marketing carries real legal exposure under consent, quiet hours and carrier registration rules, and the compliance obligation sits with the merchant, not the platform.
  • It is SMS and MMS only, so email, push and on-site messaging live in a separate tool and audience suppression between the two has to be managed across systems.

Selenium

  • Flaky tests are the standing complaint: explicit waits and synchronisation are the tester’s job, where newer tools handle it automatically
  • Setup involves drivers, versions and grid infrastructure that Playwright and Cypress bundle away
  • Slower to run than tools that talk to browsers over a debugging protocol rather than WebDriver

Pricing, plan by plan

Postscript

$49/month
  • Starter$49/month
    • $0 base fee but a $49 minimum monthly spend
    • SMS at $0.015 and MMS at $0.045 per message
    • Campaigns, automations, acquisition tools and analytics
  • Growth$100/month
    • Lower per-message rates than Starter
    • Full campaign and automation feature set
    • No contract required
  • Professional$500/month
    • Rates falling towards $0.007 SMS and $0.024 MMS
    • Suited to high-volume senders
    • Upgrade or downgrade at any time
  • Enterprise$undefined/month
    • Custom pricing on a contract
    • Negotiated message rates and support terms

Selenium

Free
  • SeleniumFree
    • Full functionality
    • Unlimited tests
    • Community support

Which should you pick?

Choose Postscript if

  • You need shopify segmentation.
  • You work on Web, iOS.
  • You also want automated flows.
Postscript review

Choose Selenium if

  • You need w3c webdriver.
  • You want to start without paying.
  • You work on Linux, macOS, Windows, Web.
  • You also want many language bindings.
Selenium review

Questions people ask

Is Postscript or Selenium better?
Neither clearly leads. Postscript starts at $49/month and Selenium at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, Postscript or Selenium?
Selenium has a free tier; the other does not. Paid plans start at $49/month for Postscript and Free for Selenium.
Does Postscript or Selenium run on more platforms?
Postscript runs on Web, iOS. Selenium runs on Linux, macOS, Windows, Web.
Can I use Selenium for free?
Yes. Selenium has a free tier, so you can try it without paying. Postscript starts at $49/month.
What is Postscript best used for?
Postscript is most often used for a shopify direct-to-consumer brand that wants abandoned cart recovery by text rather than another email in an ignored inbox, a brand running a product drop where a timed broadcast to an opted-in list is the whole launch mechanism, a merchant segmenting by past purchase and variant to send replenishment reminders at the right interval, a store on headless shopify or a custom stack that still wants sms built on order data through the sdk. Of those, a shopify direct-to-consumer brand that wants abandoned cart recovery by text rather than another email in an ignored inbox and a brand running a product drop where a timed broadcast to an opted-in list is the whole launch mechanism are not what Selenium is typically brought in for.
What can Postscript do that Selenium cannot?
Postscript covers Shopify segmentation, Automated flows, Subscriber acquisition, Two-way conversations. Selenium covers W3C WebDriver, Many language bindings, Selenium Grid, Broad browser support.

Answered from the vendors’ own pages

Postscript: Is Postscript only for Shopify?

It is built for Shopify and that is where its segmentation advantage lies, but headless and non-Shopify stores are supported through an SDK with more setup work.

Selenium: Is Selenium free?

Yes, open source with no licence fee. Paid costs come from grid infrastructure or services like BrowserStack.

Postscript: What is the real cost per text?

The plan rate plus carrier fees. On Starter that is about $0.015 plus roughly $0.00418 in US carrier fees per SMS, so budget close to two cents a message before discounts.

Selenium: Selenium or Playwright?

Playwright handles waiting automatically and is faster to set up, which removes most flakiness complaints. Selenium wins on language breadth, browser coverage including Safari, and existing suites you already have.

Postscript: Is the Starter plan free?

No. The base fee is $0 but there is a $49 minimum monthly spend, so it functions as a $49 floor.

Selenium: Is Selenium still relevant?

Yes. Its WebDriver protocol is a W3C standard implemented by every major browser, and very large existing suites are not rewritten cheaply.

Postscript: Do I need a contract?

No. Contracts are offered but not required, and plans can be moved up or down at any time under usage-based billing.

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