Using email templates

Using Mailtrap email templates

Overview

Templates are edited in the Mailtrap UI, referenced by UUID from your app, and filled with Handlebars data at send time. The same template can be used with transactional and bulk (promotional) streams; pick the stream when you integrate.

Before generating SDK code: read the README of the relevant SDK repository linked below for current method signatures. Do not rely on memory.

Before generating API request bodies: use the official docs and examples below—request shapes belong in the API reference, not in guesses (including when using AI-assisted coding).

Template management via API (create/update/list outside the UI): Templates API.

Related skills: authorizing-api-requests (tokens, env vars, auth headers), sending-emails (bases and streams), testing-with-sandbox (preview sends without live delivery).

When to use

• When sending or testing emails with Mailtrap-hosted templates (UUID in the send payload)
• Creating or editing templates in the UI
• Templates CRUD via Templates API (automations, provisioning)
• API body using template_uuid and template_variables
• Handlebars conditionals, loops, escaped vs unescaped HTML

Quick reference

API operations

In the developer docs, open:

• Transactional – Send email (including template) (https://send.api.mailtrap.io)
• Bulk – Send email (including template) (https://bulk.api.mailtrap.io)

Request body variant is typically EmailFromTemplate in the interactive reference.

Authorization

Send with Authorization: Bearer $MAILTRAP_API_TOKEN on the matching stream host (send.api.mailtrap.io or bulk.api.mailtrap.io). Token scope, storage, and the alternative Api-Token header are covered in skill authorizing-api-requests.

Example (curl) — template send

curl -X POST https://send.api.mailtrap.io/api/send \
  -H "Authorization: Bearer $MAILTRAP_API_TOKEN" \
  -H "Content-Type: application/json" \
  -d '{
    "from": {"email": "[email protected]", "name": "Your App"},
    "to": [{"email": "[email protected]"}],
    "template_uuid": "your-uuid",
    "template_variables": {"user_name": "Jane"}
  }'

Payload shape

Replace literal text/html with template fields, for example:

• template_uuid (from the template Integration tab)
• template_variables (object whose keys match Handlebars variables)

Exact required fields (e.g. from, to) follow the same rules as non-template sends for that stream.

Handlebars (supported patterns)

• {{name}} — escaped output; {{{html}}} — raw HTML
• {{#if}} / {{#unless}}, {{#each}}, {{#with}}
• Nested paths such as {{order.id}}
• Falsy values that suppress blocks include empty string, 0, false, empty collections (see product docs)

Full syntax and examples: Using Handlebars with Email Templates. Testing workflow: Testing templates with Handlebars. Sandbox preview sends: Send test emails (sandbox).

Where templates live

Templates in the app sidebar. UUID and stream-specific integration snippets are under each template's Integration tab.

Generating template HTML

Proactively offer to generate the template HTML when the user is creating a new template — don't wait to be asked. The output must be a real email template — not arbitrary web HTML — and must be mobile-compatible (responsive, renders well across email clients and screen sizes).

SDKs

• Node.js
• Python
• PHP
• Ruby
• Java
• .NET
• CLI

Common mistakes

Mistake	Fix
Mixing text/html with template_uuid	Use template fields per API schema for template sends
Skipping sandbox for risky changes	Preview with sandbox sending / Testing API (see testing-with-sandbox and send test emails)