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Browse focused browser-side utilities and filter by the topic that best matches your current debugging workflow.
66 tools
Calculate your exact age in years, months, and days, plus total days lived, weeks, and your next birthday countdown.
Convert between Advanced SubStation Alpha (.ass) and SubRip (.srt) subtitle files entirely in your browser. Strips styling tags, preserves timing, handles multi-line cues.
Encode text or files to Base64, or decode Base64 strings back to plain text.
Batch compress, convert, and optimize images directly in your browser. Supports WebP, JPG, PNG with instant preview and download all at one click. No upload required.
Merge two SRT subtitle files into a dual-language ASS or SRT file — entirely in your browser.
Calculate your Body Mass Index instantly with metric or imperial units and see your healthy weight range.
Review whether a Cache-Control header strategy is coherent before no-store, no-cache, max-age, immutable, and revalidation hints start fighting each other.
Build Unix file permissions visually with checkboxes and get the octal value, symbolic notation, and chmod command instantly.
Convert colors between HEX, RGB, and HSL formats instantly with live preview and contrast checking.
Calculate how money grows over time with compound interest. Supports monthly contributions and multiple compounding frequencies.
Check whether a browser request will pass CORS based on the request method, custom headers, credentials mode, and the response headers your API returns.
Professional-grade Cron expression parser. Supports 5-7 field formats (seconds/years), real-time field decomposition, and validation.
Enterprise-grade bidirectional data converter. Instantly transform CSV to JSON, or JSON to CSV using the robust PapaParse engine. Handles large data sets safely in your browser.
Convert CSV data to SQL INSERT or CREATE TABLE statements. Support multiple SQL dialects (MySQL, PostgreSQL, SQLite, T-SQL) with automatic type detection.
Generate cURL commands quickly by configuring HTTP method, URL, headers, body, and authentication options through an interactive form.
Clean Bilibili or AcFun XML danmaku files by removing spam, repeated comments, or thinning density for better video visibility.
High-performance XML to ASS subtitle converter. Transform Bilibili/AcFun danmaku into high-quality, collision-free subtitles for Potplayer, IINA, VLC, and Movist.
Calculate the exact number of days, weeks, and months between two selected dates, with an optional filter for working days.
Validate and audit .env files for errors, security risks, and best practices. Detect missing values, malformed syntax, insecure patterns, and configuration issues.
Generate MD5, SHA-1, SHA-256, and SHA-512 hashes from any text — updates live as you type.
Encode special characters to HTML entities or decode entities back to plain text, with a quick-reference table.
Search common HTTP status codes, compare confusing client and server failures, and keep a sharper API debugging checklist in the browser.
High-performance browser-based PNG, JPG, WebP image compression. Reduce file size by up to 90% without losing quality. No upload required, 100% private.
Professional browser-based tool to crop images and add customizable rounded corners. Features precise aspect ratio controls and instant PNG export with transparency. No server upload, 100% private.
Calculate the subnet boundary for one IPv4 CIDR block, including mask, broadcast, wildcard, and usable host range without leaving the browser.
Batch-prepare Japanese bank transfer rows for Zengin upload — bank lookup, half-width katakana, fixed-width export.
Check whether Japanese text is under, over, or exactly on a target character limit such as 200, 400, 600, or 800 characters.
The definitive tool to convert Japanese text for bank forms. Instantly switch between Zenkaku (Full-width) and Hankaku (Half-width) Katakana, numbers, and symbols.
Batch-validate Japanese qualified invoice registration numbers (T-numbers) for the 2023 Invoice System. Checks syntax, digit count, and check digit locally using the NTA's official algorithm.
Convert Japanese text into 200-cell or 400-cell manuscript-paper length and estimate how many genkouyoushi sheets a draft will require.
Estimate silent reading time and read-aloud duration from Japanese character count for scripts, speeches, lessons, and study materials.
A specialized character counter designed for Japanese text. Instantly analyze Hiragana, Katakana, Kanji distributions, and total character limits.
Instantly conjugate Japanese verbs into Masu, Te, Nai, Past, Potential, and other essential forms. Supports Godan, Ichidan, and Irregular verbs.
Extract and convert hard-coded subtitles from Jianying or CapCut draft JSON files into standard SRT or ASS formats.
Paste Japanese text to see which kanji belong to JLPT N5, N4, N3, N2, or N1+. Useful for learners checking material difficulty and authors targeting a specific JLPT level.
Enterprise-grade professional JavaScript compression tool powered by Terser Engine. Supports ES6+, variable mangling, and dead code elimination for production builds.
Convert plain text into JSON-safe escaped strings, reverse escaped values back to readable text, and catch double-escaping mistakes in API workflows.
A high-performance, strictly local JSON formatter and validator with beautiful syntax highlighting. Format or minify your JSON instantly.
Strict, fast, and secure client-side JSON validator. Features live syntax highlighting, exact error line detection, and detailed context snippets.
Decode and inspect JWT tokens instantly to view headers, payloads, and expiration status locally in your browser.
Convert between hiragana, katakana, and Hepburn romaji. Handles sokuon (っ), long vowels (ー), small ya/yu/yo combinations, and ん before vowels.
Measure the ratio of kanji, hiragana, katakana, and romaji in a Japanese passage. Use the kanji percentage to gauge reading difficulty for textbooks, blogs, JLPT prep, and editorial content.
A real-time, side-by-side Markdown editor and visual preview tool supporting GitHub Flavored Markdown (GFM).
High-precision number system conversion tool. Instantly convert between Binary, Octal, Decimal, Hexadecimal, Base 32, and Base 36 with BigInt support.
Generate cryptographically strong, random passwords using the browser's native Web Crypto API. Fully customizable, private, and secure.
Solve the three most common percentage questions: find a percentage of a value, find what percent one number is of another, and calculate percent change.
An interactive, field-level visualizer for Prisma ORM. Turn schema text into a browsable ER diagram with automated layout, relationship tracing, and dark mode support.
Test regular expressions with real-time highlighting, flag toggles, and group capture breakdown.
Inspect raw Set-Cookie response headers, surface effective attributes, and flag browser policy issues such as SameSite=None without Secure.
A fast, privacy-friendly, client-side tool to format, indent, and beautify your raw SQL queries instantly.
Convert any string to camelCase, PascalCase, snake_case, kebab-case, and 6 more formats instantly.
Validate subtitle files for character-per-second (CPS) limits, line length, and timing overlaps to ensure readability.
Offset and re-scale SRT, ASS, or WebVTT subtitle timing. Combine a millisecond shift with an FPS conversion (23.976 ↔ 25 etc.) to re-sync subs to a different video source.
Compare two text documents to find differences instantly. Features precise line, word, and character-level diffing with a GitHub-style unified view.
Quickly convert Unix epoch timestamps to human-readable dates and local times, and vice versa.
Calculate tip amount and split the bill evenly between any number of people with quick tip percentage presets.
Decode percent-encoded URL strings back to human-readable plain text.
Encode a full URL or a single nested component with the right boundary, then copy a clean result for redirects, query parameters, and callback links.
Inspect a full URL, decode query values, group duplicate keys, and flag suspicious tracking parameters directly in your browser.
Parse one raw user-agent string and identify browser family, version, engine, operating system, device type, and likely bot traffic.
Generate cryptographically secure UUID v4 identifiers in bulk.
Bidirectional WebVTT (.vtt) and SubRip (.srt) subtitle converter. Strips VTT cue settings, speaker tags, and inline styling. Runs entirely in your browser.
Format, validate, and minify XML in the browser with exact parse-error location.
Strictly format, validate, and beautify your YAML configurations. Instantly detect syntax errors with line-level precision. Essential for Docker and Kubernetes.
Audit fixed-width Zengin (.txt) files for field length violations, invalid Zenkaku characters in Hankaku fields, and trailer hash total mismatches.
Transform opaque, fixed-width Zengin (.txt) bank files into readable CSV format for Excel auditing and reconciliation.
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