# Postscript

**Canonical:** https://apis.io/providers/postscript/  
**Website:** https://postscript.io  
**APIs profiled:** 8

Postscript is an SMS and RCS marketing platform built for Shopify brands, covering list growth, campaign and automation delivery, conversational messaging, AI shopping assistants and TCPA compliance. Its developer surface is the Partner API v2 at api.postscript.io, a twenty-operation REST API authenticated with private API keys, through which partners and enterprise shops read and update SMS subscribers, read opt-in keywords, push custom events into Flow Builder, send promotional, transactional and conversational messages, manage webhook subscriptions for shop and subscriber lifecycle events, and run compliance unsubscribe and redaction operations. A browser JavaScript SDK carries the onsite opt-in popups, the checkout consent checkbox and browse-behaviour event tracking.

## Kin Score — 65.5 / 100 (strong)

Scored 2026-08-20 under rubric 0.12.0. Trend: flat (+0.0 from 65.5).

| Facet | Score |
|---|---|
| Discoverability | 81.5 |
| Contract Quality | 70.8 |
| Governance | 16.7 |
| Contract Governance | 16.7 |
| Operational Transparency | 59.2 |
| Developer Ergonomics | 41.1 |
| Commercial Clarity | 96.1 |
| Access Clarity | 96.1 |

Regulatory layer — **Telecommunications**: 46.5 (matched via tags).

## Agent readiness — 48.8 (agent-ready)

| Dimension | Value |
|---|---|
| Spec Presence | yes |
| Agentic Access | derived |
| Reversibility Documented | no |
| MCP Server | documented |
| Auth Clarity | yes |
| Idempotency | no |
| Error Semantics | documented |
| OpenAPI Examples | verified |
| Rate Limit Signal | documented |
| Event Surface Described | yes |
| Agent Skills | derived |
| Well Known Catalog | no |
| Consent Identity | no |
| Agent Card | no |
| Dry Run Mode | no |

## Access

Freemium · Self-serve signup · API access gated to Professional/Enterprise — onboarding: self-serve, pricing: freemium, trial: yes (confidence: high).

## APIs (8)

- **Postscript Partner API** — The Postscript Partner API v2 enables partners and Shopify shops to manage SMS subscribers, read opt-in keywords, send custom events into Flow Builder, send SMS and MMS messages...
- **Postscript Subscribers API** — Read, filter, page and update a shop's SMS subscribers. Filters use suffixed operators (__eq, __gt, __contains, __in) across created_at, updated_at, email, phone_number, shopify...
- **Postscript Events API** — Send custom events for use in Postscript Flows and triggers.
- **Postscript Keywords API** — Read the opt-in keywords a shop has configured for subscriber acquisition and attribution.
- **Postscript Messages API** — Send promotional, transactional or conversational SMS and MMS to an existing subscriber, and read the resulting message request and sent message.
- **Postscript Webhooks API** — Create, read, update and delete webhook subscriptions, fetch the Postscript-Signature signing token, retrieve example event payloads and trigger test deliveries.
- **Postscript Compliance API** — TCPA opt-out and data redaction for a subscriber, addressable by subscriber id, phone, email or Shopify customer id.
- **Postscript Identity API** — Verify which partner or shop the calling API token resolves to.

## MCP servers (1)

- **Postscript MCP Server**

## Agentic access (1)

- **Postscript Agentic Access** — 20 operations · 9 acting

## Security (4)

- **Postscript Authentication** — apiKey · 2 schemes
- **Postscript Domain Security** — TLSv1.3 · HSTS · DMARC
- **Postscript Vulnerability Disclosure** — disclosure policy published
- **Postscript Trust Center** — SOC 2, GDPR

## Plans (1)

- **Postscript Plans Pricing**

## Tags

SMS, Marketing, Messaging, E-Commerce, Shopify, RCS, Subscribers, Webhook, Compliance

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Profiled by [API Evangelist](https://apievangelist.com) and published on [APIs.io](https://apis.io/providers/postscript/). Scores are computed from the provider's own public artifacts under a published rubric.