Prompt variable templater
Fill named variables without executing template code.
Prompt variable templater
How to use Prompt variable templater
Prompt variable templater fills {{placeholders}} in a prompt with values from a JSON object you provide, using plain text substitution with no template code executed. Placeholder names start with a letter or underscore and may contain dots or hyphens, spaces inside the braces are allowed, and any placeholder without a matching key stops the run with a list of the missing names.
- Paste the source into the input editor, or load the built-in example.
- Set variables (json object).
- Run prompt variable templater, review the output, then use the available copy or download controls.
What this tool supports
Fill named variables without executing template code.
- Variables (JSON object)
- Set this value for your task.
Limits and processing
Text operations generally accept up to 2,000,000 characters. Individual parsers, generators and formulas apply additional limits shown by their controls.
Example source
Explain {{topic}} to {{audience}} with one example.Frequently asked questions
How do I format variables for the prompt templater?
Enter a single JSON object whose keys match your placeholder names, for example topic and audience keys for {{topic}} and {{audience}}. Arrays, plain strings and invalid JSON are rejected with the message that variables must be a JSON object.
What happens if a variable is missing from the JSON?
The tool lists every placeholder that has no matching key, for example Missing variables: audience, and produces no output until you add them. Extra keys that do not appear in the template are ignored.
Can I use nested objects or dotted names like {{user.name}}?
Dotted names are allowed but matched literally, so {{user.name}} needs a top-level key named user.name; nested lookup is not performed. If a value is itself an object or array, it is inserted as compact JSON text.
Where is my input processed?
This operation processes its source in your browser. Copy and download are explicit actions; source input is not saved in an account or history.
What are the input limits?
Text operations generally accept up to 2,000,000 characters. Individual parsers, generators and formulas apply additional limits shown by their controls.