Free text tools, online, in-browser

Why text tools should not need a server

Writers and editors handle text that nobody else should see yet. A draft of a book chapter. A draft that cannot leave the organisation yet. Internal material before it goes out. A press release under embargo. The content has value and often has obligations attached to it. Pasting any of it into a free online word counter or grammar tool means handing a copy to a third party whose retention policy you have not read.

For everyday text jobs the work is small enough that no server is needed in the first place. Counting words is a one-line function. Diffing two strings is a well-understood algorithm with mature JavaScript libraries. Converting case is regex on the input. None of it benefits from a round trip to a remote machine.

In-browser tools just do the work where the data already is. The text you paste stays in the textarea. The result appears next to it. When you close the tab everything is gone.

How the text tools work

Every text tool on this site is a small JavaScript module. The word counter splits on whitespace and counts the resulting array. The diff tool uses a longest-common-subsequence algorithm to find the minimum set of insertions and deletions between two strings. The case converter applies a sequence of regex transformations to map between camelCase, snake_case, kebab-case, and similar conventions. The readability checker applies the Flesch and Flesch-Kincaid formulas to the sentence and syllable counts of the input.

None of this requires a network connection. The page loads once, the JavaScript runs in your tab, and the work happens in milliseconds. The CSP on every page setsconnect-src 'none', so the browser would block any outbound fetch anyway, providing a hard guarantee that nothing leaks.

In-browser text tools vs the alternatives

For a one-off count, a quick diff, or converting some identifiers from snake_case to camelCase, in-browser is the obvious choice. For full editing and grammar checking on a long document, a word processor is the right tool. The two complement each other.

When to use these tools

• Editing a draft? Track changes between two versions with the diff comparison tool and keep an eye on length using the word and character counter.
• Cleaning up a copy-pasted list? Sort lines alphabetically and remove duplicates, then use find and replace with regex to normalise formatting.
• Renaming variables across a snippet? Switch identifiers between camelCase, snake_case, and other naming styles using the case converter.
• Mocking up a layout? Drop in placeholder copy from the Lorem Ipsum generator, then test how dense it reads with the readability score checker.
• Need a URL-safe slug for a blog post or filename? Convert any heading with the slug generator.

Frequently asked questions

Are these text tools free?

Yes. No character limits, no daily quotas, no account, no ads, no email signup. Paste in whatever you want and the result appears.

Is my text sent to a server?

No. Every tool runs as JavaScript inside your browser tab. All processing is local.

Do these tools process text locally?

Yes. All processing runs in your browser. For content with specific legal or compliance requirements, the verify-local page explains the browser-level technical controls in detail.

Will the diff tool handle large documents?

Up to a point. The diff runs in your browser, so the limit is your device's memory. A few hundred KB of text is fine. Comparing two 10 MB log files will work but may take a few seconds to render.

Does the word counter match what desktop word processors count?

Yes, by the same convention. Words are separated by whitespace, hyphenated terms count as one word, numbers count as words. Character counts include and exclude spaces, both shown.

Are readability scores accurate?

The Flesch-Kincaid and related scores are widely used heuristics based on average sentence length and syllable count. They are not a substitute for actual reader testing, but they are widely accepted as a rough proxy.

Can I use the case converter on identifiers in source code?

Yes. The case converter handles camelCase, snake_case, kebab-case, PascalCase, CONSTANT_CASE, dot.case, and Title Case. It is designed for converting identifiers safely without mangling acronyms.