generated: '2026-08-13'
method: searched
source: https://github.com/ActiveCampaign/postmark-mcp
description: >-
  Postmark ships an official, first-party MCP server. It is distributed ONLY as
  a local-stdio npm package — there is no hosted remote endpoint an MCP client
  can POST to. Postmark's own landing page (https://postmarkapp.com/lp/mcp)
  gives a single install path: `npx -y @activecampaign/postmark-mcp` in the
  client's mcpServers config.
provider: Postmark
providerId: postmark
status: official
name: Postmark MCP Server
repository: https://github.com/ActiveCampaign/postmark-mcp
landing_page: https://postmarkapp.com/lp/mcp
license: MIT
version: 2.1.1
version_published: '2026-07-13'

deployment:
  mode: local-stdio
  endpoint: null
  install: npx -y @activecampaign/postmark-mcp
  package: https://www.npmjs.com/package/@activecampaign/postmark-mcp
  auth: api-key
  verified: searched

deployment_note: >-
  mode is local-stdio, not remote. Postmark publishes no MCP URL. Every
  configuration example on the vendor landing page and in the repository README
  uses `command: npx` / `command: node` with stdio transport and environment
  variables — a human must install and run the server on a machine before any
  agent can reach Postmark through it. Probed https://mcp.postmarkapp.com/mcp
  (DNS does not resolve, curl exit code 6 / recorded 000) and
  https://postmarkapp.com/mcp (404) on 2026-08-13 to confirm no hosted surface
  exists; no endpoint URL is recorded because guessing one would read as a
  verified agent surface.

configuration:
  required:
    - name: POSTMARK_SERVER_TOKEN
      description: Postmark server API token (X-Postmark-Server-Token).
    - name: DEFAULT_SENDER_EMAIL
      description: Default From address; must be a verified sender signature.
    - name: DEFAULT_MESSAGE_STREAM
      description: Message stream, e.g. `outbound`.
  optional:
    - name: AGENT_LABEL
      description: Sent as X-Agent-Label on every Postmark API request.
    - name: WEBHOOK_URL_ALLOWLIST
      description: Comma-separated HTTPS URL prefixes createWebhook will accept.
    - name: LOG_FILE
      description: Path for appended structured JSON logs.
    - name: LOG_EMAIL_FULL
      default: 'false'
      description: Set true to disable mailbox masking in logs.

clients_documented:
  - Claude Desktop
  - Cursor
  - Windsurf
  - any MCP client accepting the standard mcpServers JSON config

runtime:
  requires: Node.js v20 or higher
  transport: stdio
  request_headers:
    - name: X-Postmark-Client
      value: postmark-mcp
    - name: X-Postmark-Client-Version
      value: matches the MCP server package version
    - name: X-Postmark-MCP-Client
      value: MCP host app name/version from the initialize handshake
    - name: X-Agent-Label
      value: value of AGENT_LABEL when set

security_posture:
  token_scope: >-
    The server acts with the full permissions of POSTMARK_SERVER_TOKEN. Postmark
    tokens are not sub-scopable — a Server Token grants every operation on its
    server. The vendor's documented mitigation is structural: dedicate a
    Postmark server to MCP traffic.
  annotations: >-
    All 24 tools carry MCP readOnlyHint / destructiveHint / idempotentHint
    annotations so clients can auto-approve reads and gate mutations.
  webhook_policy: HTTPS enforced at the schema level; optional URL allowlist.
  logging: Structured JSON to stderr; mailbox portion of email addresses masked by default.
  prompt_injection: >-
    Vendor explicitly documents prompt-injection risk because the server can
    send email and register webhooks.

tool_count: 24
tools:
  - name: sendEmail
    category: Email
    mutating: true
  - name: sendEmailWithTemplate
    category: Email
    mutating: true
  - name: sendBatch
    category: Email
    mutating: true
  - name: sendBatchWithTemplate
    category: Email
    mutating: true
  - name: listTemplates
    category: Templates
    mutating: false
  - name: getTemplate
    category: Templates
    mutating: false
  - name: createTemplate
    category: Templates
    mutating: true
  - name: editTemplate
    category: Templates
    mutating: true
  - name: deleteTemplate
    category: Templates
    mutating: true
    destructive: true
  - name: validateTemplate
    category: Templates
    mutating: false
  - name: searchOutboundMessages
    category: Messages
    mutating: false
  - name: getMessageDetails
    category: Messages
    mutating: false
  - name: diagnoseDelivery
    category: Diagnostics
    mutating: false
    note: >-
      Composite tool with no single REST equivalent — fans out across message
      search, suppressions and bounce history, then returns a plain-English
      recommendation.
  - name: searchBounces
    category: Bounces
    mutating: false
  - name: getBounceDump
    category: Bounces
    mutating: false
  - name: activateBounce
    category: Bounces
    mutating: true
  - name: listSuppressions
    category: Suppressions
    mutating: false
  - name: createSuppressions
    category: Suppressions
    mutating: true
  - name: deleteSuppressions
    category: Suppressions
    mutating: true
    destructive: true
  - name: getDeliveryStats
    category: Stats & Server
    mutating: false
    note: >-
      One tool fronting the whole Stats API via a `stat` selector: summary,
      overview, sent, bounces, spam, tracked, opens, openPlatforms, openClients,
      openReadTimes, clicks, clickBrowsers, clickPlatforms, clickLocation.
  - name: getServerInfo
    category: Stats & Server
    mutating: false
  - name: listWebhooks
    category: Webhooks
    mutating: false
  - name: createWebhook
    category: Webhooks
    mutating: true
  - name: deleteWebhook
    category: Webhooks
    mutating: true
    destructive: true

history:
  - date: '2025-06-27'
    event: Initial MCP server released via Postmark Labs.
    source: https://postmarkapp.com/updates
  - date: '2026-07-14'
    event: v2.0 — 24 tools, diagnoseDelivery, tool annotations, tighter security defaults.
    source: https://postmarkapp.com/updates