Rewrite a String
A tiny string rewriting system. Runs entirely in your browser, so your data never leaves your device.
0 chars · 0 lines
Output
The result appears here as you type.
How to use Rewrite a String
- 1. Paste your text. Enter the text you want transformed into the input pane, such as the red cat or a longer passage with terms you want systematically rewritten.
- 2. Define your rewrite rules. Enter one rule per line in Rules using the format find=replace, so the red cat becomes the blue dog by pairing red=blue and cat=dog on separate lines.
- 3. Copy the rewritten text. Copy the result from the output pane once every rule has been applied to the input, producing a text fully transformed according to your rewriting system.
When to use Rewrite a String
Rewrite a String applies a small set of find and replace rules as a lightweight rewriting system, transforming text token by token according to rules you define. It's for experiments with formal grammars, simple word substitution games and template-driven text generation.
- Prototyping a simple string rewriting system. You're learning about formal grammars and want to see how a small set of substitution rules transforms a sentence step by step, without writing a parser from scratch.
- Building a mad-libs style text generator. A word game swaps specific nouns and adjectives in a fixed sentence template for silly alternatives. Defining the swap rules here produces the transformed sentence instantly.
- Applying a consistent vocabulary change across a passage. A style guide update renames a handful of terms throughout a document, and you want to define and apply all those substitutions together rather than one at a time.
- Exploring how a substitution cipher transforms text. You're teaching or learning about substitution ciphers and want to define a small rule set mapping certain words or letters to others, then see the transformed output immediately.
Examples
Rewrite a string with rules
Input
the red cat
Output
the blue dog
About the Rewrite a String tool
Rewrite a String runs as plain JavaScript in your browser tab, with no server behind it. A tiny string rewriting system. Whatever you put in stays on your device from start to finish.
The tool is part of EditSafely's String Tools section, 159 single-purpose utilities built around the same idea: open the page, get the result, keep your data to yourself.
You can shape the output with the Rules (one per line, find=replace) setting, and the result refreshes the moment you change it. A worked example further down the page shows exactly what the tool produces for a real input.
That local-first design has practical benefits beyond privacy. The tool keeps working on a flaky connection once the page has loaded, results are instant because nothing round-trips to a server, and it is safe to use with confidential material.
Frequently asked questions
Is Rewrite a String free to use?
Yes, it is completely free. All 2,658 tools on EditSafely work without an account, a subscription or usage limits.
Is it safe to paste sensitive or confidential data?
Everything happens locally. Your browser downloads the tool's code once, then does all the processing itself; nothing you enter is transmitted, stored or logged. You can even go offline after the page loads and it will still work.
How much text can I process at once?
There is no fixed limit. Because the work happens on your own device rather than on a shared server, the practical ceiling is your machine's memory, which comfortably handles inputs far larger than typical online tools allow.
Do I need to sign up or install anything?
No. The tool works in any modern browser on desktop, tablet or phone. There is no account to create, no extension to add and no software to install.
How do I use the result?
The output panel has a one-click copy button, and you can keep refining the input while you work; the result updates in place as you type.