Templates

Relevant source files

The following files were used as context for generating this wiki page:

• src/Service/Template.php
• src/Template.php
• tests/Service/Template.php
• tests/Fixtures/Template.php
• tests/ValueObjects/Transporter/Payload.php

Templates provide a system for managing reusable email content within the Resend platform. This module allows you to create, version, and organize email layouts using HTML and plain text with dynamic variable substitution.

The system distinguishes between draft and published states, enabling controlled updates to email communications. Developers interact with templates through the Template service, which handles the communication with the Resend API to perform CRUD operations, publishing, and duplication of template resources.

Template Resource Model

The Template class represents the data structure of an email template. It includes metadata, content, and configuration for variables.

Data Structure

The following table describes the fields available in a template resource:

Field	Type	Description
id	string	Unique identifier for the template.
name	string	Human-readable name of the template.
alias	string	Unique string identifier used to reference the template.
status	string	Current state: published or draft.
from	string	Default sender email address.
subject	string	Default subject line for emails sent with this template.
html	string	HTML content of the email.
text	string	Plain text fallback content.
variables	array	Collection of keys and types used for dynamic replacement.
created_at	string	ISO timestamp of creation.

Sources: src/Template.php:6-21, tests/Fixtures/Template.php:5-28

Variables Configuration

Templates support dynamic content through a variables array. Each variable entry defines a key, a type (such as string), and an optional fallback_value.

'variables' => [
    [
        'id' => 'e169aa45-1ecf-4183-9955-b1499d5701d3',
        'key' => 'user_name',
        'type' => 'string',
        'fallback_value' => 'John Doe',
    ],
]

Sources: tests/Fixtures/Template.php:18-27

Template Service Architecture

The Resend\Service\Template class executes API operations by constructing specific Payload objects and passing them to a Transporter.

Service Methods

The service implements seven primary operations to manage the template lifecycle:

1. get(string $id): Retrieves a specific template by its ID.
2. create(array $parameters): Generates a new template resource.
3. list(array $options): Returns a paginated collection of all templates.
4. update(string $id, array $parameters): Modifies an existing template.
5. remove(string $id): Deletes a template from the system.
6. publish(string $id): Transitions a template from draft to published status.
7. duplicate(string $id): Creates a copy of an existing template.

Sources: src/Service/Template.php:14-94

Data Flow Diagram

The following diagram illustrates how the Template service interacts with the internal Transporter and the Payload value object to execute an API request.

This flow ensures that request parameters are validated and formatted into the correct HTTP methods before transmission.
Sources: src/Service/Template.php:25-33, tests/ValueObjects/Transporter/Payload.php:115-125

Template Lifecycle and Operations

Templates follow a specific lifecycle involving creation, modification, and publication.

Lifecycle Management

When you create a template, it typically begins as a draft. You must explicitly publish it to make it active for production use.

The diagram shows the transition states between draft and published versions.
Sources: src/Service/Template.php:75-94, tests/Service/Template.php:67-93

Operation Summary

Operation	HTTP Method	Endpoint
Create	POST	/templates
Get	GET	/templates/{id}
Update	PATCH	/templates/{id}
List	GET	/templates
Delete	DELETE	/templates/{id}
Publish	POST	/templates/{id}/publish
Duplicate	POST	/templates/{id}/duplicate

Sources: src/Service/Template.php:14-94, tests/Service/Template.php:7-93

Technical Implementation Details

The implementation relies on the Payload value object to define HTTP behaviors like method types and path construction.

Payload Construction

For operations like publish and duplicate, the system sends a POST request with an empty JSON body ({}).

$payload = Payload::publish('templates', $id);
$result = $this->transporter->request($payload);

Sources: src/Service/Template.php:77-79, tests/ValueObjects/Transporter/Payload.php:115-125

Pagination

The list method supports pagination options including limit, before, and after. These are passed as query parameters to the Resend API.

Sources: src/Service/Template.php:39-49, tests/ValueObjects/Transporter/Payload.php:48-55

Templates allow developers to decouple email design from application logic. By utilizing the Template service, you manage content via IDs and aliases, ensuring that layout changes do not require code deployments.