25 tools available

Text & Writing Utilities

Browser-native utility tools that execute 100% locally on your computer. No user accounts, registration, or server-side communication.

Text Character Encoding Converter

You can mutually convert the character code of text and files to Shift_JIS, EUC-JP, UTF-8, etc., and decipher and repair garbled characters.

Reactencoding-japanese
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Regex Extractor

Extracts all strings that match regular expressions (emails, URLs, phone numbers, etc.) from text at once.

ReactRegex MatchAll
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Ngram Analyzer

We aggregate and analyze the sequential appearance patterns (N-grams) of letters and words in sentences, as well as related words that tend to appear together with specific words (co-occurrence words).

Reacttiny-segmenter
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Word Counter

In addition to the number of characters and lines, full-width/half-width discrimination, number of manuscript paper equivalents, etc. are counted in real time on the browser.

ReactRegex processing
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Secure Notepad

This is a local memo pad that automatically saves entered text so that data will not be lost even if you accidentally close the tab.

ReactLocalStorage API
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Text Diff Checker

Compares two sentences and highlights added parts (green) and deleted parts (red) by line, word, or character.

ReactMyers Diff
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Duplicate Line Remover

Batch deletes duplicate lines from multiple lines of text and sorts and formats them in ascending order, descending order, length order, etc.

ReactSorting Algorithm
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Case Converter

Convert text character formats at once, including uppercase/lowercase, camel, snake, full-width/half-width, hiragana/katakana, etc.

ReactString Utilities
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List Converter

Converts a comma-separated string (CSV-like data) to a list of line breaks, or vice versa, by adding quotes.

ReactFormatting Engine
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Text Replacer

Replace specific characters or strings in text at once using case sensitivity and regular expression patterns.

ReactRegex Replacer
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Csv Transposer

Preview the CSV data vertically (rows) and horizontally (columns) in table format, flip it, and re-output.

ReactCSV Parser
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JSON XML Converter

Bidirectionally converts JSON format object data to XML tag structure or XML to JSON format.

ReactDOMParser API
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Whitespace Trimmer

Remove or clean up extra spaces at the beginning and end of lines, consecutive spaces, and unnecessary line breaks in text at once.

ReactRegex Engine
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Dummy Story Generator

Automatically generates English Lorem Ipsum and Japanese classical literature-style dummy sentences for web design comps and development verification.

ReactMock Text
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User Agent Analyzer

Analyzes the User-Agent string sent by the browser and visualizes OS, browser, and device information.

ReactUA Parser
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Text Metrics Visualizer

This is a writing support tool that visualizes the length distribution of each paragraph/sentence of input text and the appearance ratio of punctuation marks (,.) in real time using a histogram.

ReactCustom SVG Charts
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JSON Csv Flattener

Converts complex JSON data and CSV data with nested structures by mutually flattening the hierarchy.

ReactJSON/CSV Engines
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Morse Code Generator

We perform mutual conversion between Japanese (Japanese), alphanumeric characters (Roman) and Morse code, and perform pronunciation playback simulation using Web Audio API.

ReactWeb Audio API
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Text Obfuscator

As a countermeasure against automatic email collection spambots, email addresses and phone numbers are converted into HTML entity references and obfuscated JavaScript code.

ReactObfuscation Engines
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Csv Column Editor

Sort the columns of the uploaded CSV file, rewrite the header, delete unnecessary columns, and extract row data conditionally.

ReactCSV Parser/Serializer
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Text Sorter

Automatically sorts multiple lines of text or list data in alphabetical order, numerical order, character length order, random order, etc.

ReactCustom Sort Functions
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JSON Schema Validator

Verify whether the input JSON data meets the requirements defined by JSON Schema (type, required items, value range, etc.).

ReactJSON Schema Engine
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Markdown HTML Converter

Converts Markdown (Markdown notation) documents and HTML code in both directions. Fully equipped with preview display function.

ReactDOMParser API
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Text Splitter

Smartly divides and slices long sentences according to the 140 character limit and API limit of X (formerly Twitter).

ReactText Boundary Splitter
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Proofreading Tool

Detects and proofreads unnatural expressions in Japanese (double negatives, omitted words, redundant expressions, double words, etc.) and fluctuations in the spelling of okurikana.

ReactRegEx Diagnostic Engine
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Secure Client-Side Sandbox

All tools displayed in this category run locally in your browser sandbox. None of the inputs, file data, or processing logs are sent to any remote servers or APIs.

Category Architecture & Guide

Text & Writing Utilities: Comprehensive Guide

Diff checking, encoding converters, deduplication, and regex extraction

Comparing contract drafts, sanitizing log files, repairing encoding issues, and extracting patterns from raw text are common daily tasks. Pasting unreleased drafts or confidential text into cloud-hosted tools creates serious compliance risks. ZeroTools processes text datasets locally, delivering high-speed analysis even on large multi-megabyte documents.

Safe Proofreading of Sensitive Drafts

Review legal contracts, embargoed press releases, and internal meeting minutes with zero leak exposure.

High-Performance Text Streaming

Optimized string processing algorithms handle tens of thousands of lines smoothly in local memory.

Universal Format Conversions

Easily switch between Markdown, HTML, CSV, JSON, and Unicode escape sequences.

1Granular Diff Comparison & Character Encoding Repair

Compare texts and source code with word-by-word and character-by-character visual diff highlights. Repair garbled CSV files (Shift_JIS ⇔ UTF-8) with automatic encoding detection directly in your browser.

2Deduplication, Sorting & Pattern Extraction

Clean large email lists and server logs with instant duplicate removal, natural sorting, and regular expression pattern extraction for URLs, IPs, and email addresses with no UI freezing.

Frequently Asked Questions

Q.Is pasted text used for AI training or external logging?
No. ZeroTools never sends your text to external servers, cloud databases, or AI training pipelines.
Q.Can it handle large text files without crashing?
Yes, our memory-efficient algorithms are optimized to process large datasets without locking up your browser.