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Documentation Index

Fetch the complete documentation index at: https://docs.senderkit.com/llms.txt

Use this file to discover all available pages before exploring further.

A template is mostly fixed text with a few holes — a name, a link, an amount. Variables are how you fill those holes at send time. The template owns the wording; your send call owns the data.

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The syntax

SenderKit interpolates templates with Mustache. You reference a variable with double braces, and nested values with a dotted path:
Template copy
Hi {{first_name}},

Your reset link is ready. It expires in {{expiry_minutes}} minutes:
{{reset_url}}
Your send
await senderkit.send({
  template: "password-reset",
  to: "user@example.com",
  vars: {
    first_name: "Ada",
    reset_url: "https://app.example.com/reset?t=abc123",
    expiry_minutes: 30,
  },
});

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Typed variables

Each template version declares the variables it expects, with a type (string, array, object, or boolean), an optional description, an example value, and whether it’s required. The editor uses these declarations to preview the template with realistic sample data, and to help non-engineers understand what each hole needs.
Declarations describe and document the variables a template uses — they power previews and the editor experience. At send time, interpolation is driven by the vars you actually pass.

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Missing variables

If a template references a variable you don’t supply, it renders as an empty string — interpolation doesn’t fail, and the send still goes out. That keeps a forgotten optional field from blocking delivery, but it also means a typo in a variable name fails silently.
Catch missing variables before you send. The render endpoint (POST /v1/templates/{slug}/render) returns the rendered output plus a missing array listing every variable the template referenced but you didn’t provide. See the API Reference.

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Escaping

For email, values interpolated into the HTML body are HTML-escaped by default, so a variable can’t inject markup. Subjects, preheaders, plain-text bodies, and all SMS and push content are not HTML, so they pass through unescaped. When you genuinely need a variable to contain trusted HTML, opt out of escaping with the triple-brace / ampersand form: 
{{&promo_banner_html}}
{{&var}} injects the value as raw HTML. Only use it for content you control — never for anything a user can influence — or you open an HTML-injection hole.

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Conditionals and loops

Mustache sections let a template show a block only when a value is present, or repeat a block over a list: 
{{#has_trial}}Your trial ends on {{trial_end}}.{{/has_trial}}
{{^has_trial}}Thanks for being a paid customer.{{/has_trial}}

{{#line_items}}
- {{name}}: {{amount}}
{{/line_items}}
In the email editor these map to repeat and show-if blocks, so non-engineers can build conditional and repeating content visually without writing Mustache.

Templates

Where variables are declared and used.

Sending

How vars travel with a send.