> ## Documentation Index > Fetch the complete documentation index at: https://zenskar.com/docs/llms.txt > Use this file to discover all available pages before exploring further. # Templating guide ## Overview Every document Zenskar generates on your behalf, invoices, credit notes, payment receipts, refund receipts, and contracts, starts as an HTML template written in [**Mustache**](https://mustache.github.io/), a logic-less templating language. You write the layout once in **Communications > Document Templates**; Zenskar fills in the placeholders with real data each time a document is generated and converts the result to PDF. This page covers the parts of Mustache and template authoring that apply to every document type. For the variables specific to one document type, see its reference page: Line items, totals, tax breakdowns, and payment details. Adjustment reasons, amounts, and links back to the original invoice. Proof of transaction, payment method, and receipt IDs. Reversal details and the original payment reference. Legal terms, service periods, and signature blocks. *** ## How Mustache works Zenskar renders templates with standard Mustache syntax: * **Variables**: `{{variable_name}}` is replaced with a value, for example a customer's name. Zenskar HTML-escapes variables by default; if a value legitimately contains markup (an address with embedded `
` line breaks, for instance), use the unescaped, triple-brace form instead: `{{{variable_name}}}`. * **Sections**: `{{#document_lines}} ... {{/document_lines}}` repeats the enclosed block once per item in a list, used for line items, tiers, and similar repeating data. * **Inverted sections**: `{{^field}} ... {{/field}}` renders the enclosed block only when `field` is empty, false, or absent. This is the standard way to provide fallback content for an optional field, for example: ```html theme={null} {{#customer.tax_id}} Tax ID: {{customer.tax_id}} {{/customer.tax_id}} ``` renders the tax ID line only when the customer has one on file, and simply omits it otherwise. ### Syntax quick reference | Syntax | Behavior | | ------------------------------- | ---------------------------------------------------------------------------------------------------- | | `{{variable}}` | Renders the variable, HTML-escaped | | `{{{variable}}}` | Renders the variable without HTML-escaping, for values that legitimately contain markup | | `{{#variable}}...{{/variable}}` | Renders the enclosed block once per item if `variable` is a non-empty array, or once if it is truthy | | `{{^variable}}...{{/variable}}` | Renders the enclosed block only if `variable` is falsy, empty, or absent | | `{{.}}` | Inside a section, refers to the current item's own value rather than a named field | *** ## Data type conventions Every document-type reference page below expresses each variable's type using the same conventions: | Type | Format | Example | | ----------------- | ----------------------------------------------------------------- | ------------------------------- | | String (Currency) | Pre-formatted with currency symbol and thousands separators | `"$1,234.56"` | | String (Number) | Pre-formatted with thousands separators | `"1,234"` | | String (Date) | Human-readable date | `"Jan 15, 2024"` | | String (URL) | Absolute URL | `"https://example.com/invoice"` | | String (Email) | Email address | `"customer@example.com"` | | String (HTML) | Contains markup; render with the unescaped `{{{ }}}` form | `"123 Main St
Suite 100"` | | Boolean | Used to gate a section or inverted section, not rendered directly | `true` / `false` | | Integer | Whole number, typically an indentation level | `0`, `1`, `2` | | Array | A list rendered with a section | `[{...}, {...}]` | *** ## Common variables The following variables are available across billing document templates (Invoice, Credit Note, Payment Receipt, Refund Receipt, Contract): | Variable | Description | | ------------------------ | ------------------------------------------------------------------------------------------------- | | `{{logo}}` | Your organization's logo URL | | `{{{customer.address}}}` | Customer's billing address (use the triple-brace form; the value may contain `
` line breaks) | | `{{customer.name}}` | Customer's full name | | `{{customer.email}}` | Customer's billing email | | `{{{seller.address}}}` | Your company's address, as configured in Settings (triple-brace form) | | `{{seller.name}}` | Your company name, as configured in Settings | Amount and currency values are exposed pre-formatted for display (for example `{{invoice_data.total}}`), rather than as a separate raw currency-code variable. See the document-type-specific reference pages above for the exact fields available on each document. *** ## Writing template HTML that renders well as a PDF Zenskar converts your template HTML to PDF after Mustache substitution runs. Because HTML-to-PDF rendering can differ from how a browser renders the same markup, follow these practices: * **Set explicit heights.** Set `height: 100%;` on `html` and `body` so background colors and full-bleed elements extend to the edge of the page instead of collapsing to the height of the content. * **Force color printing.** Browsers and PDF engines often skip background colors and images by default when printing. Add: ```css theme={null} body { -webkit-print-color-adjust: exact; print-color-adjust: exact; } ``` * **Control page breaks.** Apply `page-break-inside: avoid;` to table rows or containers that must not be split across a page boundary, such as a line-item row or a totals block. * **Use semantic table markup.** Structure tables with ``, ``, and `` rather than plain `
` grids, so headers can repeat correctly if a document spans multiple pages. * **Choose broadly-supported fonts.** Pick a font family with good international character and currency-symbol coverage, and self-host or inline it. Avoid linking external CSS files, since they may not be available at render time. * **Preview before you rely on it.** Open **Communications > Document Templates**, select your template, and click **Preview** to render it against sample data. Preview renders the HTML directly and is a fast way to check layout, but it is not the same rendering path as the final PDF. Before rolling a template out, generate a real document (for example a test invoice) and confirm the PDF output matches what you expect. *** ## Starting a new template without an existing one to copy A brand-new document template's code editor opens completely empty. Zenskar does not provide starter or boilerplate HTML, a duplicate action, or a reset-to-default option. If a template of the same type already exists in the same organization, opening it and clicking **Edit HTML** shows working markup that already uses Zenskar's placeholders correctly, and that markup can be used as a starting point for a new template of the same type. Avoid these two shortcuts, since both can carry the wrong branding or data into a new template: * **Copying a template's Preview output.** Preview shows placeholders already resolved against sample data, so its HTML contains literal, resolved values rather than live `{{placeholders}}`. * **Copying HTML from a different Zenskar organization or environment**, such as a sandbox or test account. That organization's branding, sample data, or hardcoded values can end up baked into the new template instead of being filled in per customer. If neither option applies, build the HTML from scratch using the document-type-specific variable reference pages linked above, then confirm the result with Preview and a real test document before relying on it. See [Document templates](/docs/20240301/product-modules/more/communications/document-templates) for the full editing workflow.