generated: '2026-08-13'
method: searched
source: https://postmarkapp.com/updates
docs: https://postmarkapp.com/updates
description: >-
  Postmark publishes a dated, categorised product changelog at
  https://postmarkapp.com/updates ("Latest updates"), filterable by Web, Mobile,
  API, Labs, Libraries and Company. 106 dated entries were readable on
  2026-08-13, the oldest reaching back to 2013. The recent window is captured
  below. NOTE: the ChangeLog link previously carried in apis.yml
  (https://postmarkapp.com/changelog) returns 404 — /updates is the live page.
provider: Postmark
providerId: postmark

scheme:
  api_versioning: unversioned
  version_pinning: false
  changelog_form: dated editorial post list, categorised
  machine_readable: false
  rss: null
  note: >-
    There is no version number to track. Breaking changes are announced as dated
    posts with lead time (e.g. the 2022-09-01 HTTP deprecation carried a
    2022-09-12 reminder), and there is no way for a client to pin behaviour.
  current_version: null

categories:
  - Web
  - Mobile
  - API
  - Labs
  - Libraries
  - Company

entries:
  - date: '2026-07-14'
    category: Labs
    title: "Postmark's MCP server: now with 24 tools and delivery diagnostics"
    breaking: false
    additions:
      - 24 MCP tools across email, templates, messages, bounces, suppressions, stats, server info and webhooks
      - diagnoseDelivery composite tool
      - MCP read-only / destructive / idempotent tool annotations
      - Masked-by-default logging, HTTPS enforcement, optional webhook URL allowlist

  - date: '2026-06-09'
    category: Libraries
    title: 'Python SDK v0.3.0: now with sync support'
    breaking: false
    additions:
      - Synchronous wrapper alongside the async-first client
      - Sync and async variants of every example

  - date: '2026-04-30'
    category: Libraries
    title: Python SDK now available
    breaking: false
    additions:
      - Official async-first Python SDK (Python 3.10+), ServerClient and AccountClient

  - date: '2026-03-05'
    category: API
    title: Send bulk email at scale
    breaking: false
    additions:
      - New Bulk API — content defined once at request level, recipient list supplied separately
      - Up to 50 MB per request including attachments
      - Status endpoint reporting percentage delivered
    note: >-
      Broadcast streams only; must be enabled per account by support. Distinct
      from the Batch API, which sends different messages to different recipients.

  - date: '2026-02-27'
    category: Labs
    title: 'Postmark Skills: Teach AI coding agents how to send email'
    breaking: false
    additions:
      - Five open-source Agent Skills (send-email, inbound, templates, webhooks, email-best-practices)

  - date: '2026-02-18'
    category: Libraries
    title: postmark.js 4.0.7
    breaking: false

  - date: '2025-10-15'
    category: Labs
    title: Give AI assistants context about Postmark with llms.txt
    breaking: false
    additions:
      - Published https://postmarkapp.com/llms.txt

  - date: '2025-08-06'
    category: Web
    title: Pro and Platform tier features now accessible to lower-volume plans
    breaking: false

  - date: '2025-06-27'
    category: API
    title: 'Postmark Labs: New MCP Server for AI-Powered Email'
    breaking: false
    additions:
      - First release of the Postmark MCP server

  - date: '2025-06-25'
    category: Libraries
    title: 'PHP SDK Update: Now Supports PHP 8.4'
    breaking: false

  - date: '2024-11-13'
    category: Web
    title: Introducing the Postman collection for Postmark
    breaking: false

  - date: '2023-12-13'
    category: Libraries
    title: "Updates to Postmark's JS and PHP libraries"
    breaking: false

  - date: '2023-12-08'
    category: API
    title: Introducing the Postmark Data Removal API
    breaking: false
    additions:
      - Data Removal request + status endpoints

  - date: '2023-10-31'
    category: API
    title: Changes to Email API validation – Action may be required
    breaking: true
    highlights:
      - Tightened Email API request validation; existing integrations could start failing.

  - date: '2023-07-18'
    category: API
    title: 'Static IP Deprecation: Postmark will no longer support IP allow-listing for our API'
    breaking: true
    highlights:
      - Removed a network-layer control customers used to restrict API access.

  - date: '2023-05-22'
    category: API
    title: Introducing the Retention Add-on
    breaking: false

  - date: '2023-02-20'
    category: API
    title: "Introducing Postmark's new Status API (powered by Sorry™)"
    breaking: false

  - date: '2022-09-01'
    category: API
    title: 'Upcoming changes: Postmark will no longer support API requests over HTTP'
    breaking: true
    highlights:
      - HTTPS became mandatory for all API requests; reminder announcement posted 2022-09-12.

  - date: '2022-05-03'
    category: Company
    title: Postmark has been acquired by ActiveCampaign
    breaking: false
    highlights:
      - Explains why every first-party repository now lives under github.com/ActiveCampaign
        and why the PHP package is still published as wildbit/postmark-php.

  - date: '2021-07-29'
    category: API
    title: 'Introducing SMTP Tokens: Expanded support for using Broadcast Message Streams via SMTP'
    breaking: false

  - date: '2021-06-30'
    category: API
    title: Introducing Sandbox Mode, a safe environment for email testing
    breaking: false

entry_count_window: 21
entry_count_published_total: 106
window: '2021-06-30 to 2026-07-14'
breaking_changes_in_window: 3