Email template tester
Preview and inspect transactional email templates.
Your input stays on this device. Nothing is uploaded or saved.
About Email template tester
Render a small HTML email template using escaped {{name}} string substitutions.
When to use it
Check email copy with sample recipient values.
Template: <h1>Hello {{name}}</h1>
Values: {"name":"Ada"}How to use it
- Paste HTML with named placeholders.
- Provide named string values as JSON.
- Render the isolated preview and inspect the output.
Limits & privacy
Up to 64 KiB. Preview runs in an isolated frame with scripts, forms, popups and remote images disabled. Rendering is a browser approximation, not an email-client compatibility test. HTML output is untrusted and is not sanitized for insertion into another application. Up to 100 values of 4,096 characters each, with rendered output limited to 256 KiB. Supports simple substitutions only; no loops, helpers or executable expressions. Unmatched placeholders remain visible.
Use this tool from the API reference or connect through the SDK, CLI, SSH, or MCP. Hosted calls share your plan allowances.