Postscript

SMS marketing platform built for Shopify direct-to-consumer brands. Deepest Shopify integration of any SMS platform.

Capabilities

Authentication

• Type: API Key
• Header: Authorization: Bearer {api_key} or X-Postscript-Api-Key: {api_key}
• Get key: Postscript dashboard → Settings → API
• Note: Keys are scoped per shop

Common Agent Operations

Search subscribers

GET https://api.postscript.io/api/v2/subscribers?phone_number=%2B15551234567

Create subscriber (opt-in)

POST https://api.postscript.io/api/v2/subscribers

{
  "phone_number": "+15551234567",
  "email": "[email protected]",
  "first_name": "Jane",
  "subscribed_at": "2026-05-15T10:00:00Z",
  "opt_in_source": "checkout_keyword"
}

Must include valid opt-in metadata for TCPA compliance.

Unsubscribe

DELETE https://api.postscript.io/api/v2/subscribers/{subscriberId}/subscription

List keywords (e.g., JOIN, SAVE)

GET https://api.postscript.io/api/v2/keywords

Send transactional message

POST https://api.postscript.io/api/v2/transactional/sms

{
  "phone_number": "+15551234567",
  "message": "Your order #1234 shipped. Track at https://..."
}

Transactional requires separate enablement; counts under transactional consent.

List campaigns

GET https://api.postscript.io/api/v2/campaigns

List automations (flows)

GET https://api.postscript.io/api/v2/automations

Webhooks

Subscribe to events: subscriber.created, subscriber.unsubscribed, message.delivered, message.failed, conversion.attributed.

API Pattern

REST + JSON. Standard Bearer auth. Pagination via cursor and limit (max 100).

Key Features

• Native Shopify integration: purchases, abandoned carts, browse, product catalog auto-sync
• Strong abandoned cart and browse abandonment automation builders
• AI Reply (auto-reply trained on brand voice)
• Conversational SMS / live agent for two-way
• Opt-in tools: popups, keyword opt-in, checkout opt-in
• A2P 10DLC managed in-platform
• Reporting: revenue, click-through, conversion attribution, opt-out rate

Pricing

• Plans: Starter (free, 1K msgs/mo), Growth ($100+/mo), Professional, Enterprise
• Per-send pricing on top: ~$0.015 SMS, ~$0.04 MMS
• Annual contracts standard at Growth+
• Pricing scales meaningfully past 50K subscribers

When to Use

• Shopify DTC brand wanting SMS-specific tooling (vs combined email/SMS)
• Need deep abandoned cart, browse abandonment, post-purchase automation out of the box
• Want managed A2P 10DLC + compliance tools
• Mid-size DTC brand (10K–500K SMS subscribers)

When NOT to Use

• Non-Shopify ecom — integration is shallow
• Already on Klaviyo for email and SMS is secondary — Klaviyo SMS is simpler
• Mid-market/enterprise needing concierge support — Attentive
• Custom platform or B2B SaaS — Twilio

Relevant Skills

• sms
• emails (run alongside via Klaviyo or similar)
• churn-prevention (win-back flows)
• onboarding (post-purchase activation)