Quickly Build Dynamic AI Prompts with Template Engine

Xano's Template Engine is one of the most powerful utility functions available for creating dynamic, data-driven content — and it's especially useful when building AI prompts, HTML email templates, or SQL queries. Instead of chaining together multiple sprintf filters and replace operations, you can define a single template with clean, readable syntax and let Xano do the heavy lifting.

Getting Started with the Template Engine

You'll find the Template Engine under the Add Function menu, inside Utility Functions. Once added, it gives you a centralized editor where you write your template using double curly brackets {{ }} to inject dynamic values. For example, {{ var.user.name | title }} pulls a name from a database record and applies a title-case filter — all in one expression.

This replaces the older approach of building a text variable and stacking sprintf and replace filters on top of it. The result is cleaner, easier to maintain, and far more readable.

Using Conditionals and Loops

What makes the Template Engine feel like a full templating language is its support for logic. You can write if statements using the {% %} syntax to conditionally display content. For example, you can check whether a user has a VIP flag in their database record and return personalized messaging based on that value.

Loops work the same way. Use {% for item in list %} to iterate over an array — such as a list of order items — and output structured content for each entry. You can even perform inline math operations inside the template, like multiplying item.price by item.quantity to display a calculated total, all within the template itself.

Escaping and Sanitizing Values

When working with HTML, CSS, or JavaScript content, you'll want to use the e filter to sanitize values before saving or rendering them. This ensures special characters are properly escaped and your templates remain safe and error-free when stored in your database or delivered to users.

Building AI Prompts the Smart Way

One of the most compelling use cases is generating dynamic AI prompts. Imagine pulling a customer's purchase history, interests, preferred communication style, and company details — then assembling all of that into a single, well-structured prompt in just a few function stack steps. You can even add conditional logic inside the prompt itself, like checking the current month to include holiday-specific instructions for the AI model.

Once the AI returns its response, you can use a second template to extract and format the output — turning raw AI text into a polished, ready-to-send email.

Practical Applications

Beyond AI prompts, the Template Engine shines for:

• HTML email templates with dynamic user data, order loops, and VIP conditionals
• SQL query construction with variable inputs
• Personalized content delivery based on user attributes

Whether you're a developer or a no-code builder, the Template Engine simplifies the process of creating highly customized outputs from your Xano data.