Text Cleaner Online — Remove Duplicates, Whitespace & Hidden Formatting

How does the Remove Duplicate Lines mode work?

This mode scans through all lines in your text and keeps only the first occurrence of each unique line, removing any subsequent duplicates. Importantly, it preserves the original order of lines — the first time each unique line appears, it stays in that position. For example, if you have a list with 'apple' on line 1, 'banana' on line 2, 'apple' again on line 3, the output will be 'apple' then 'banana' with the second 'apple' removed. The comparison is exact and case-sensitive: 'Apple' and 'apple' are treated as different lines. The implementation uses a JavaScript Set data structure, which provides O(1) average-time lookups for detecting duplicates efficiently even in large files.

Source: MDN Web Docs — Set (JavaScript Data Structure)

What's the difference between Remove Extra Whitespace and Strip All Formatting?

Remove Extra Whitespace focuses specifically on normalizing visible spacing while keeping the text structure intact. It converts multiple consecutive spaces or tabs into a single space, removes leading and trailing spaces from each line, and reduces excessive blank lines (more than two in a row) to a maximum of two. Your line breaks and paragraph structure remain intact. Strip All Formatting, on the other hand, is more aggressive — it removes all invisible control characters (like carriage returns, form feeds, null bytes), zero-width spaces, and other non-printable Unicode characters that can cause problems when pasting text between applications. Use Remove Extra Whitespace for general cleanup and readability; use Strip All Formatting when you suspect hidden characters are causing issues.

Can I remove multiple types of characters at once with Custom mode?

Yes. In Remove Custom Characters mode, simply type all the characters you want to remove in the input field, with no separators needed. For example, typing '@#$%&*' will remove all six of those symbols from your text in a single pass. You can include letters, numbers, punctuation, or even spaces in the custom removal list. The tool treats each character individually and removes every occurrence. This is useful for cleaning scraped data, removing formatting artifacts, stripping unwanted punctuation from code, or preparing text for specific systems that don't accept certain characters.

Does this tool work with Unicode, emoji, and non-English text?

Yes. The tool handles full UTF-8 and Unicode input correctly, including emoji (😊 🚀), accented characters (é ñ ü), Chinese/Japanese/Korean text (中文 日本語 한국어), Arabic script, Cyrillic, and all other Unicode character sets. Each cleaning mode respects Unicode boundaries and won't corrupt multi-byte characters. For example, Remove Extra Whitespace will correctly normalize spacing around emoji and CJK characters, and Remove Duplicate Lines will compare full Unicode strings. The only exception is Strip All Formatting, which intentionally removes certain invisible Unicode characters like zero-width spaces (U+200B) and formatting marks — but it preserves all visible Unicode text. The Unicode Standard defines over 150,000 characters across 161 scripts as of version 16.0.

Source: The Unicode Consortium — The Unicode Standard

Is my text data safe when using this tool?

Absolutely. This text cleaner runs entirely in your browser using JavaScript — no network request is ever made. Your input text is never uploaded to any server, never stored in any database, and never logged anywhere. You can safely clean sensitive content like personal notes, confidential documents, API responses, database exports, or any other private text. The processing happens locally on your device using client-side JavaScript string methods. When you close or refresh the page, all input and output is immediately cleared from memory. For additional privacy, the tool works even if you disconnect from the internet after loading the page.

Source: MDN — String.prototype.replace()

What are zero-width spaces and why does Strip All Formatting remove them?

Zero-width spaces (U+200B), zero-width non-joiners (U+200C), zero-width joiners (U+200D), and other invisible Unicode characters are formatting marks that occupy no visible space but affect text rendering and processing. They are inserted by word processors, rich text editors, and some websites for purposes like soft line-break hints and bidirectional text control. These invisible characters cause problems when pasting text into code editors, terminal commands, database fields, or other systems that expect clean plain text — they can break string comparisons, cause mysterious parsing errors, and inflate character counts. The Strip All Formatting mode removes all Unicode category Cf (format) and Cc (control) characters except standard whitespace (spaces, tabs, newlines), leaving only visible, printable text. After stripping hidden characters, you can change text casing with the <a href="/tools/case-converter/">Case Converter</a> or sort and rearrange content with the <a href="/tools/text-transformer/">Text Transformer</a>.

Source: Unicode Technical Report #44 — General Category Values

Can this clean up AI-generated text from ChatGPT or other LLMs?

Yes — this text cleaner is ideal for cleaning AI-generated content. Text from ChatGPT, Claude, Gemini, and other AI tools often contains extra whitespace, inconsistent line breaks, unwanted bullet characters, and invisible formatting when copied. Use Remove Extra Whitespace to normalize spacing, Remove Line Breaks to convert multi-paragraph output into continuous text, or Strip All Formatting to remove any hidden Unicode artifacts. The Custom Character mode is especially useful for stripping markdown symbols (*, #, -, >) that AI tools include in their output. Content writers and marketers frequently use this tool to prepare AI-generated drafts for publishing in CMS platforms like WordPress, Notion, and Google Docs.

How do I remove extra spaces and line breaks from text?

Use the Remove Extra Whitespace mode to normalize all spacing in your text — it converts multiple consecutive spaces to a single space, removes leading and trailing spaces from each line, and reduces excessive blank lines to a maximum of two. If you need to eliminate all line breaks entirely (turning multi-line text into a single continuous line), use the Remove Line Breaks mode instead. Both modes work in real-time as you paste or type text, showing the cleaned output instantly with statistics on how many characters and lines were removed. This is especially useful for cleaning text copied from PDFs, emails, or web pages where formatting artifacts create irregular spacing.