Overview
Introduction
Adding a fixed prefix to text, a namespace, a protocol, a tag, is a one-line operation in code but still convenient to have as a standalone tool for quick edits.
It runs entirely client-side, so nothing you paste is ever uploaded to a server.
What Is Prefix Adder?
A prefixing tool that concatenates your chosen prefix in front of the input text.
It runs entirely client-side as part of this site's String Tools collection, so nothing you paste is ever uploaded to a server.
How Prefix Adder Works
The tool simply returns `prefix + input`.
The transformation happens synchronously in JavaScript the moment you type, with no network round trip involved.
When To Use Prefix Adder
Use it to quickly prepend a namespace to an identifier, a protocol to a URL, or a tag to a filename.
It's a fast way to get the answer without opening a code editor, a REPL, or writing a one-off script just to check.
Often used alongside Suffix Adder and Find & Replace Tool.
Features
Advantages
- Simple and predictable, a direct string concatenation.
Limitations
- Adds the prefix once to the whole input, not per line.
Examples
Best Practices & Notes
Best Practices
- For per-line prefixing across multiple lines, process each line individually rather than relying on a single whole-input prefix.
Developer Notes
The implementation is a single string concatenation (`prefix + input`), with no per-line splitting.
Prefix Adder Use Cases
- Prepending a namespace to a variable or identifier
- Adding a protocol prefix to a bare domain
- Tagging a filename with a fixed prefix
Common Mistakes
- Expecting the prefix to be added to every line of multi-line input.
Tips
- Use Add a Suffix to a String for the equivalent operation at the end of the text.