Postscript website screenshot

Postscript

Postscript is an SMS marketing and sales platform built for Shopify brands, providing list growth tools, campaign delivery, RCS messaging, and AI-driven shopping assistants alongside a developer API for building custom SMS experiences.

Postscript publishes 3 APIs on the APIs.io network: Events API, Subscribers API, and Webhooks API. Tagged areas include SMS, Marketing, Messaging, E-commerce, and Shopify.

Postscript’s developer surface includes authentication, documentation, getting-started guide, API reference, changelog, pricing, engineering blog, and 12 more developer resources.

🌐 Visit website 📡 Source on GitHub
46.9/100 developing ▬ flat Agent 31/100 agent aware Full breakdown ↓
scored 2026-07-28 · rubric v0.6
AccessFreemiumSelf serve⚡ Free to try
4 APIs
SMSMarketingMessagingE-commerceShopifyRCSSubscribers

Kin Score

Kin Score Kin Score How this is scored →
scored 2026-07-28 · rubric v0.6
Composite quality — 46.9/100 · developing
Contract Quality 13.8 / 25
Developer Ergonomics 10.0 / 20
Commercial Clarity 13.2 / 20
Operational Transparency 6.2 / 13
Governance 0.0 / 12
Discoverability 6.5 / 10
Agent readiness — 31/100 · agent aware
Machine-Readable Contract 18 / 18
Agentic Access Contract 10 / 10
MCP Server 0 / 12
Machine-Readable Auth 10 / 10
Idempotency 0 / 9
Stable Error Semantics 0 / 8
Request/Response Examples 0 / 7
Rate-Limit Signaling 7 / 7
Typed Event Surface 0 / 6
Agent Skills 0 / 5
Well-Known Catalog 0 / 4
Consent & Bot Identity 0 / 3
A2A Agent Card 0 / 8
Dry-Run / Simulate Mode 0 / 4
Improve this rating by publishing the missing artifacts — every area above can be raised, and the full rubric is at apis.io/rating/. This rating is computed from github.com/api-evangelist/postscript: open an issue to ask a question, or submit a pull request to add artifacts. Want it done for you? Prioritized profiling — $2,500 →

APIs 4

Individual APIs this provider publishes, each with its own machine-readable definition.

Postscript API

The Postscript API enables developers to manage SMS subscribers, send messages, configure keywords, trigger events, and integrate the Postscript platform with external commerce ...

Postscript Events API

Send custom events for use in flows and triggers.

Postscript Subscribers API

Manage SMS subscribers.

Postscript Webhooks API

Configure webhook subscriptions for Postscript events.

Open Collections 1

Open, tool-agnostic API collections (OpenAPI-derived and Bruno).

Postscript API

OPEN COLLECTION

Pricing Plans 1

Published pricing tiers and plan structures.

Postscript Plans Pricing

3 plans

PLANS

Rate Limits 1

Documented rate limits and quota policies.

Postscript Rate Limits

5 limits

RATE LIMITS

FinOps 1

Cost, billing, and metering signals for API financial operations.

Postscript Finops

FINOPS

Security Posture 4

Authentication, domain security, vulnerability disclosure, and trust-center signals.

Postscript Authentication

http · 1 scheme

SECURITY

Postscript Domain Security

TLSv1.3 · HSTS · DMARC

SECURITY

Postscript Vulnerability Disclosure

disclosure policy published

SECURITY

Postscript Trust Center

SOC 2, GDPR

SECURITY

Agentic Access 1

Recommended x-agentic-access execution contracts for AI agents.

Postscript Agentic Access

9 operations · 6 acting

9 operations · 6 acting

AGENTIC

Resources

Get Started 1

Portal, sign-up, and the first successful call

GettingStarted
GettingStarted

Documentation 2

Reference material describing how the API behaves

Documentation
Documentation
 APIReference
APIReference

Agent Surfaces 2

MCP servers, agent skills, and machine-readable catalogs

AgenticAccess
AgenticAccess
 LlmsText
LlmsText

Build 1

SDKs, sample code, and the tooling you integrate with

SDKs
SDKs

Access & Security 6

Authentication, authorization, and security posture

TrustCenter
TrustCenter
 VulnerabilityDisclosure
VulnerabilityDisclosure
 DomainSecurity
DomainSecurity
 Authentication
Authentication
 Authentication
Authentication
 Compliance
Compliance

Operate 3

Status, limits, changes, and where to get help

RateLimits
RateLimits
 ChangeLog
ChangeLog
 Support
Support

Commercial 1

Pricing, plans, and the legal terms of use

Pricing
Pricing

Company 3

The organization behind the API

LinkedIn
LinkedIn
 Website
Website
 Blog
Blog

Source (apis.yml)

apis.yml Raw ↑ 
aid: postscript
name: Postscript
description: Postscript is an SMS marketing and sales platform built for Shopify brands, providing list growth tools, campaign
  delivery, RCS messaging, and AI-driven shopping assistants alongside a developer API for building custom SMS experiences.
type: Index
accessModel:
  pricing: freemium
  onboarding: self-serve
  trial: false
  try_now: true
  public: false
  label: Freemium · Self-serve signup
  confidence: high
  source:
  - plans
  - authentication
  generated: '2026-07-22'
  method: derived
image: https://kinlane-images.s3.amazonaws.com/shared/apis-json/icons/postscript.png
tags:
- SMS
- Marketing
- Messaging
- E-commerce
- Shopify
- RCS
- Subscribers
url: https://raw.githubusercontent.com/api-evangelist/postscript/refs/heads/main/apis.yml
created: '2025-01-01'
modified: '2026-04-28'
specificationVersion: '0.19'
apis:
- aid: postscript:postscript-api
  name: Postscript API
  description: The Postscript API enables developers to manage SMS subscribers, send messages, configure keywords, trigger
    events, and integrate the Postscript platform with external commerce and marketing systems.
  humanURL: https://developers.postscript.io
  tags:
  - SMS
  - Subscribers
  - Messages
  - Keywords
  - Events
  - Shop
  properties:
  - type: Documentation
    url: https://developers.postscript.io
  - type: GettingStarted
    url: https://developers.postscript.io/docs/getting-started
  - type: Authentication
    url: https://developers.postscript.io/docs/api-authentication
  - type: RateLimits
    url: https://developers.postscript.io/docs/rate-limits
  - type: APIReference
    url: https://developers.postscript.io/reference
  - type: ChangeLog
    url: https://developers.postscript.io/changelog
  - type: Webhooks
    url: https://developers.postscript.io/docs/configuring-webhooks
- aid: postscript:postscript-events-api
  name: Postscript Events API
  description: Send custom events for use in flows and triggers.
  humanURL: https://developers.postscript.io
  tags:
  - Events
  properties:
  - type: OpenAPI
    url: openapi/postscript-events-api-openapi.yml
- aid: postscript:postscript-subscribers-api
  name: Postscript Subscribers API
  description: Manage SMS subscribers.
  humanURL: https://developers.postscript.io
  tags:
  - Subscribers
  properties:
  - type: OpenAPI
    url: openapi/postscript-subscribers-api-openapi.yml
- aid: postscript:postscript-webhooks-api
  name: Postscript Webhooks API
  description: Configure webhook subscriptions for Postscript events.
  humanURL: https://developers.postscript.io
  tags:
  - Webhooks
  properties:
  - type: OpenAPI
    url: openapi/postscript-webhooks-api-openapi.yml
common:
- type: AgenticAccess
  url: agentic-access/postscript-agentic-access.yml
- type: TrustCenter
  url: security/postscript-trust-center.yml
- type: VulnerabilityDisclosure
  url: security/postscript-vulnerability-disclosure.yml
- type: DomainSecurity
  url: security/postscript-domain-security.yml
- type: Authentication
  url: authentication/postscript-authentication.yml
- type: LinkedIn
  url: https://www.linkedin.com/company/postscriptio
- type: Website
  url: https://postscript.io
- type: Documentation
  url: https://developers.postscript.io
- type: GettingStarted
  url: https://developers.postscript.io/docs/getting-started
- type: Authentication
  url: https://developers.postscript.io/docs/api-authentication
- type: RateLimits
  url: https://developers.postscript.io/docs/rate-limits
- type: Compliance
  url: https://developers.postscript.io/docs/compliance
- type: APIReference
  url: https://developers.postscript.io/reference
- type: ChangeLog
  url: https://developers.postscript.io/changelog
- type: SDKs
  url: https://developers.postscript.io/docs/javascript-sdk-api-reference
- type: Integrations
  url: https://developers.postscript.io/docs/how-to-use-zapier-with-our-api
- type: Pricing
  url: https://postscript.io/pricing
- type: Blog
  url: https://postscript.io/blog
- type: Support
  url: https://help.postscript.io
- type: LlmsText
  url: https://developers.postscript.io/llms.txt
integrations:
- name: Postscript
- name: True Classic CaseStudy-FEATURE IMG
- name: Integration-hero_img
maintainers:
- FN: Kin Lane
  email: kin@apievangelist.com