# Text & test data tools

Find text problems and test input boundaries.

Canonical: https://tamperbox.dev/categories/text-testdata

Updated: 2026-10-29

Reviewed: 2026-10-26

Find text problems and test input boundaries.

## Choose a check

Inspect invisible or ambiguous characters, recover supported encoding mistakes, or generate hostile and exact-length strings. These browser tools support text-input QA; generated cases are examples, not proof that an application is secure. Use active payloads only against systems you may test.

## Tools in this collection

- [Hidden Character Checker](https://tamperbox.dev/hidden-characters): **Two strings look identical but behave differently? Find what's hiding in them.**

  Find invisible and look-alike characters, count length every way, clean text.
- [Naughty Strings List](https://tamperbox.dev/naughty-strings): **Find inputs your form probably wasn't expecting.**

  158 hostile test strings that say what they test, copied as JSON, CSV or code.
- [Exact-Length String Generator](https://tamperbox.dev/string-length-generator): **Test a field right at its length limit, and just beyond it.**

  Strings of an exact length in characters or bytes, limit sets and counterstrings.
- [Mojibake Fixer](https://tamperbox.dev/mojibake-fixer): **Your text turned into strange symbols. See whether it can be recovered.**

  Turn garbled UTF-8 text back into what was written, and see what was lost.

## Continue exploring

[API & HTTP tools](https://tamperbox.dev/categories/api) · [Email authentication tools](https://tamperbox.dev/categories/email) · [Domains, registration & hosting tools](https://tamperbox.dev/categories/domains) · [DNS tools](https://tamperbox.dev/categories/dns) · [Network & IP tools](https://tamperbox.dev/categories/network) · [Crawl, SEO & site checks](https://tamperbox.dev/categories/web) · [Web security & TLS tools](https://tamperbox.dev/categories/security) · [Data format tools](https://tamperbox.dev/categories/data) · [Localization tools](https://tamperbox.dev/categories/localization) · [UI testing tools](https://tamperbox.dev/categories/ui-testing)