postmark-webhooks

postmark-webhooks is a skill for Claude Code, Codex from ActiveCampaign/postmark-skills. It costs 42 tokens per session (1,808 once invoked), scanned A, original, MIT.

A guide for receiving Postmark email events through webhooks, which are HTTP requests sent to your application when something happens. Events include delivery, bounces, spam complaints, opens, clicks, and subscription changes.

In plain words
What is it for?
Use it to create and configure Postmark webhooks, receive and parse event payloads, update application records, and return the required success response securely.
Why use it?
It lets an application react to email activity as it happens instead of checking Postmark manually. This supports keeping delivery status, engagement data, mailing lists, and unsubscribe preferences up to date.

Skill for Claude CodeCodex

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

agentmods
npx agentmods add skills/activecampaign/postmark-skills/postmark-webhooks
Any agent
npx skills add ActiveCampaign/postmark-skills --skill postmark-webhooks
Clone the repo
git clone --depth 1 https://github.com/ActiveCampaign/postmark-skills

Made for: Claude Code, Codex.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for postmark-webhooks

README.md
[![agentmods](https://agentmods.dev/badge/skills/activecampaign/postmark-skills/postmark-webhooks.svg)](https://agentmods.dev/skills/activecampaign/postmark-skills/postmark-webhooks)
Your own site
<a href="https://agentmods.dev/skills/activecampaign/postmark-skills/postmark-webhooks"><img src="https://agentmods.dev/badge/skills/activecampaign/postmark-skills/postmark-webhooks.svg" alt="Measured on agentmods" height="20"></a>
Per session 42 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,808 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 1 finding. Scan, not verified.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5.1 $0.00042 $0.01808
Opus 5 $0.00021 $0.00904
Sonnet 5 $0.00008 $0.00362
Haiku 4.5 $0.00004 $0.00181

Measured 5d ago against content hash 12e8eb22ba41, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-05, from the pricing page.

Security

Grade A, and why

postmark-webhooks scanned grade A with 1 finding against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 5d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Makes network callslowCapability

Not a fault in itself. Listed so you know the mod talks to something, and to what.

curl "https://api.postmarkapp.com/webhooks" \
postmark-webhooks/SKILL.md · 183 lines

How it starts

The opening of the file, as written. The whole thing — 183 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Postmark Webhooks

Overview

Postmark webhooks deliver real-time event data to your endpoint via HTTP POST. Use webhooks to track what happens after you send an email.

Event Trigger Common Use
Delivery Email accepted by recipient server Confirm delivery, update status
Bounce Email rejected by recipient server Clean lists, alert support
SpamComplaint Recipient marked as spam Remove from lists, investigate
Open Recipient opened email (tracking pixel) Engagement analytics
Click Recipient clicked a tracked link Engagement analytics, conversion tracking
SubscriptionChange Recipient unsubscribed Update preferences, comply with regulations

Quick Start

  1. Create a webhook via API or Postmark dashboard (Server → Webhooks)
  2. Set your endpoint URL — must accept HTTP POST and return 200
  3. Select event triggers — choose which events to receive
  4. Handle payloads — parse the JSON body for each event type
  5. Respond with 200 — acknowledge receipt immediately

Webhook API

Endpoints

Endpoint Method Description
/webhooks GET List all webhooks for a message stream
/webhooks/{webhookid} GET Get a specific webhook
/webhooks POST Create a webhook
/webhooks/{webhookid} PUT Update a webhook
/webhooks/{webhookid} DELETE Delete a webhook

Create a Webhook

const postmark = require('postmark');
const client = new postmark.ServerClient(process.env.POSTMARK_SERVER_TOKEN);

const webhook = await client.createWebhook({
  Url: 'https://yourdomain.com/webhooks/postmark',
  MessageStream: 'outbound',
  HttpAuth: {
    Username: 'webhook-user',
    Password: 'webhook-secret'
  },
  HttpHeaders: [
    { Name: 'X-Custom-Header', Value: 'my-value' }
  ],
  Triggers: {
    Open: { Enabled: true, PostFirstOpenOnly: false },
    Click: { Enabled: true },
    Delivery: { Enabled: true },
    Bounce: { Enabled: true, IncludeContent: true },
    SpamComplaint: { Enabled: true, IncludeContent: true },
    SubscriptionChange: { Enabled: true }
  }
});

console.log('Webhook created:', webhook.ID);

Read the full file on GitHub · 183 lines

Files

What ships with it

5 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 5d ago First seen · 183 lines · 42 tokens per session scan A 12e8eb22ba41

Subscribe to this mod's changes

postmark-webhooks is a skill published in the GitHub repository ActiveCampaign/postmark-skills (45 stars, last pushed 17d ago), licensed MIT. It adds 42 tokens to every session and 1,808 once invoked, about $0.0002 per session on Opus 5. A static security scan graded it A with 1 finding (makes network calls). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.

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