Agent Skill · ActiveCampaign

postmark-templates

Use when creating, managing, or sending with Postmark server-side email templates — Handlebars syntax, layout inheritance, template validation, and cross-server pushing.

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Email Templates with Postmark

Overview

Postmark templates are server-side email templates using Handlebars syntax. Templates are rendered on Postmark’s servers — no client-side rendering library needed.

Feature Description
Syntax Handlebars (Mustache-compatible)
Rendering Server-side — no React, no client library
Types Standard templates and Layout templates
Inheritance Standard templates can inherit from a Layout
Validation API endpoint to test-render templates before sending
Cross-server Push templates between servers (staging → production)
Limit 100 templates per server (contact support for more)

Quick Start

  1. Create a template via API or the Postmark dashboard
  2. Define variables using Handlebars syntax: {{variable_name}}
  3. Send with template using POST /email/withTemplate or POST /email/batchWithTemplates
  4. Pass data via TemplateModel — Postmark renders and sends

Template Syntax (Handlebars)

Hello {{name}},                            {{! variable }}
{{{html_content}}}                         {{! unescaped HTML }}
{{#if premium}}Premium member{{/if}}       {{! conditional }}
{{#each items}}{{this.name}}{{/each}}      {{! iteration }}
{{customer.address.city}}                  {{! nested object }}

See references/handlebars-syntax.md for the full syntax reference including conditionals, iteration with index, nested objects, and common mistakes.

Template Types

Type TemplateType Sendable Purpose
Standard "Standard" Yes Defines subject, HTML, and text body
Layout "Layout" No Reusable wrapper injected via {{{@content}}}

Standard templates can reference a Layout via LayoutTemplate: "layout-alias". The Standard template’s body replaces {{{@content}}} in the Layout at send time.

See references/layout-templates.md for layout creation, assignment, and examples.

API Endpoints

Template CRUD

Endpoint Method Description
/templates POST Create a new template
/templates GET List all templates (?count=100&offset=0&templateType=Standard)
/templates/{idOrAlias} GET Get a single template
/templates/{idOrAlias} PUT Update a template
/templates/{idOrAlias} DELETE Delete a template
/templates/validate POST Validate template rendering
/templates/push PUT Push templates to another server

Sending with Templates

Endpoint Method Description
/email/withTemplate POST Send single email with template
/email/batchWithTemplates POST Send batch with templates (up to 500)

Send with Template

Always use TemplateAlias over TemplateId — aliases survive re-creation and work across environments:

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

await client.sendEmailWithTemplate({
  From: '[email protected]',
  To: '[email protected]',
  TemplateAlias: 'welcome-email',
  TemplateModel: {
    name: 'Jane Doe',
    product_name: 'Acme App'
  },
  MessageStream: 'outbound'
});

Validate a Template

Test-render without sending — useful in CI/CD before deploying template changes:

const validation = await client.validateTemplate({
  Subject: 'Welcome {{name}}',
  HtmlBody: '<h1>Hello {{name}}</h1>',
  TextBody: 'Hello {{name}}',
  TestRenderModel: { name: 'Test User' }
});

console.log('Valid:', validation.AllContentIsValid);
console.log('Rendered:', validation.Subject.RenderedContent);

See references/template-api.md for full CRUD operations (create, list, update, delete), batch sending, validate, and push between servers.

Common Mistakes

Mistake Fix
Using {{html}} for HTML content Use triple braces {{{html}}} for unescaped HTML
Forgetting {{{@content}}} in Layout Layout templates must include {{{@content}}} placeholder
Deleting a Layout with dependents Remove layout association from Standard templates first
Using Template ID across environments Use TemplateAlias — it survives re-creation and works across servers
Not validating before deploy Use /templates/validate to test-render before sending
Sending a Layout directly Layouts are wrappers — you can only send Standard templates
Missing TemplateModel fields Handlebars renders missing variables as empty strings — validate your data
Exceeding 100 templates Contact Postmark support to increase the per-server limit

Notes

Skill frontmatter

license: MIT metadata: {"author"=>"postmark", "version"=>"1.0.0"}