Variables

Variables are the core of what makes Promptodex prompts reusable. They let you create templates that adapt to any context.

Syntax

Variables use double curly braces:

{{variableName}}

Whitespace inside the braces is trimmed, so these are all equivalent:

{{name}}
{{ name }}
{{  name  }}

Required variables

A variable without a default value is required. If no value is provided when the prompt is rendered, it becomes an empty string.

Write a blog post about {{topic}}.

When used from the CLI:

pod blog-post --topic "AI safety"

When used from the SDK:

const prompt = await pod("blog-post", { topic: "AI safety" });

Variables with defaults

Add a default value after a colon:

{{variableName:defaultValue}}

Example:

Translate the following to {{language:english}}:

{{content}}

If language isn't provided, it defaults to english.

Multiple variables

Use as many variables as you need:

You are a {{role:assistant}} helping with {{task}}.

Please respond in {{language:english}} and keep the tone {{tone:professional}}.

{{content}}

Variable naming

Variable names should be:

• Descriptive — topic is better than t
• Lowercase — language not Language
• Hyphen/underscore-free — use camelCase or single words

Missing variables

When a variable has no default and no value is provided, it renders as an empty string:

import { renderPrompt } from "promptodex";

renderPrompt("Hello {{name}}!", {});
// "Hello !"

This behavior is by design — it keeps rendering predictable and never throws errors for missing variables.

Next Steps

• Defaults — More on default values
• Best Practices — Write better prompts