Printf / Sprintf Text
Format text with a small, explicit printf-style placeholder subset locally.
A QUICK WALKTHROUGH
How to use this tool
- Enter a template and a JSON array of primitive values.
- Use only %s, %d, %i, %f, %j, or %%.
- Format and copy the local result.
Explicit subset
Supports %s, %d, %i, %f, %j, and %%. Unsupported placeholders and missing values produce clear errors.
Bounded and local
Template and arguments are limited to 100,000 characters each. Arguments are parsed as JSON primitives and no code is evaluated.
GOOD TO KNOW
Common questions
Can it execute JavaScript?
No. It only parses a JSON array and applies the supported placeholders.
Which placeholders are supported?
%s for text, %d and %i for truncated finite numbers, %f for finite numbers, %j for JSON, and %% for a literal percent sign.
How do I pass values?
Enter a JSON array such as ["Ada", 42, true].