Markdown -> MindMap
Turn Markdown headings into a simple browser-rendered mind map tree.
Tool directory
All tools
Browse every DevToolbox utility currently available.
Markdown -> HTML
Convert Markdown into an HTML preview and source code directly in the browser.
Markdown -> PDF
Turn Markdown into a print-ready document and open the browser save-as-PDF flow.
Markdown live preview
Type Markdown or load a file and preview the rendered document instantly in the browser.
Mermaid diagram generator
Render Mermaid syntax into an SVG diagram directly in the browser.
PlantUML renderer
Encode PlantUML source in the browser and render an SVG preview only when requested.
JSON Viewer
Validate JSON and explore paths, types, and structure in a tree.
YAML Viewer
Safely validate YAML and inspect the parsed structure and JSON result.
CSV Viewer
Preview CSV files as a table and inspect row and column counts.
CSV → JSON
JSON → CSV
Text Diff
Compare two text blocks and highlight added, removed, and changed lines.
Code Diff
Compare two code snippets line by line and optionally ignore whitespace changes.
Document Summary Viewer
Extract headings, key sentences, keywords, and document statistics in the browser.
HTML Preview
Render HTML in a sandboxed preview and inspect the document structure.
TXT to PDF
Preview pasted text or a text file as a print-ready PDF document.
Markdown Wiki Viewer
Render Markdown as a wiki-style article with outline navigation.
RTF Viewer
Paragraph Formatter
Case Converter
Character Counter
Count characters, words, lines, sentences, and length without spaces.
Text Sorter
Sort line-based text ascending, descending, or with duplicates removed.
Line Break Cleaner
Clean unnecessary line breaks and blank lines around sentences.
Base64 Text Encoder
Encode UTF-8 text into Base64, URL-safe Base64, or a data URI.
Base64 Text Decoder
URL Encoder
Percent-encode URL components, query strings, or path fragments by mode.
URL Decoder
Decode percent-encoded URL text with plus-space and repeated decoding options.
Slug Generator
Convert title text into a URL slug with Unicode, separator, case, and length options.
Lorem Ipsum Generator
Generate placeholder text with selected paragraph and sentence counts.
Memo Pad
Font Comparer
OCR Result Viewer
Review OCR-extracted text, blocks, and suspicious characters.
Clipboard Tool
Clean clipboard text and save pasted or clipboard images as PNG/JPG files.
JPG to PNG
PNG to JPG
Convert PNG images to JPG with background and quality options.
WebP Converter
Export JPG, PNG, or WebP images as quality-controlled WebP files.
Image Resize
Image Compress
EXIF Viewer
EXIF Remover
Re-export an image through canvas to remove EXIF and other file metadata.
Image Crop
Crop a selected image area and export it in the chosen format.
Add Watermark
Sprite Sheet Generator
Combine multiple images into one downloadable sprite sheet PNG.
Color Palette Extractor
Rotate Image
Flip Image
Background Removal Mockup
Create a transparent PNG using edge, point, or color-key background removal.
Image Filter
Image Border
Extend Canvas
Image Format Info
Inspect an image’s actual format, dimensions, signature, alpha, and animation.
Image Compare
Compare matching image areas pixel by pixel and visualize the differences.
Placeholder Image Generator
Create a placeholder image with custom dimensions, colors, and text.
Profile Image Maker
Grayscale Image
Image Brightness
Image Contrast
Image Meta Tags
Build HTML and social metadata from an image URL and description.
ICO Converter
SVG to PNG
PNG to SVG Viewer
Embed a PNG in SVG markup for preview; this does not trace vectors.
Regex Tester
Run a regular expression against test text and inspect matches and groups.
Cron Generator
JSON Formatter
Validate and transform JSON with formatting, key sorting, slash escaping, and minified output.
SQL Formatter
Apply browser-side keyword line breaks and indentation to SQL.
Timestamp Converter
Convert Unix timestamps, milliseconds, and ISO dates to local time, UTC, and relative time.
UUID Generator
Generate secure-random UUID v4 values in the selected format and quantity.
JWT Decoder
Decode a JWT header and payload without verifying its signature.
Password Generator
Generate passwords from secure browser randomness and selected constraints.
HTML Formatter
A browser MVP formatter that applies line breaks and indentation around HTML tags.
CSS Formatter
Apply line breaks and indentation around CSS blocks, declarations, and semicolons.
JavaScript Formatter
A browser MVP formatter that tidies JavaScript around braces and semicolons.
XML Formatter
Diff Checker
Compare two texts line by line and mark added, removed, and changed lines.
Color Converter
HTACCESS Generator
Meta Tag Generator
robots.txt Generator
Build crawler allow, disallow, delay, and sitemap directives.
Sitemap.xml Builder
HTTP Status Lookup
Unicode Converter
Convert characters to Unicode code points and escape notation.
Escape / Unescape
Number Base Converter
Convert between decimal, hexadecimal, octal, and binary numbers.
QR Code Generator
MP4 to GIF
GIF Frame Inspector
Inspect frame count, timing, and dimensions in an animated GIF.
Video Compressor
Re-encode a video to a smaller WebM with width and frame-rate controls.
Frame Extractor
Video Cutter
Video Rotator
Remove Video Audio
Video Thumbnail Generator
Capture and export a thumbnail at a selected video position.
Video Resolution Resizer
Resize a video while preserving its aspect ratio and export it as WebM.
WebM Converter
Convert a browser-playable video to WebM with size and frame-rate controls.
Video Metadata Inspector
Inspect a local video’s type, size, duration, resolution, and aspect ratio.
CSV Chart
Excel Viewer
Preview local Excel or CSV files as sheet tables in the browser, then copy or download CSV.
Pivot Viewer
Build a pivot table from selected CSV fields, then copy or download the result as CSV.
Timeline Generator
Convert CSV with dates and titles into a chronological timeline SVG with SVG copy and PNG export.
Gantt Chart Generator
Convert task, start, and end date CSV into a Gantt SVG with SVG copy and PNG export.
Table Filter Builder
Filter a CSV table by search terms, then copy or download matching rows as CSV.
JSON Chart Preview
Preview a chart from label and numeric values in a JSON array with SVG copy and PNG export.
CSV Statistics Summary
Data Sampler
Extract first, last, evenly spaced, or seed-based random sample rows from CSV data.
Column Mapping Tool
Reorder CSV columns and rename headers with source:target mapping rules.
PDF Merge
Merge multiple PDF files in order and inspect file count, page count, and output size.
PDF Split
Save selected page ranges from a PDF and inspect output pages and size.
PDF Compressor
Optimize or rasterize a PDF locally with explicit quality and preservation trade-offs.
JPG to PDF
PDF to JPG
Render a selected PDF page in the browser and save it as a JPG image.
PDF Rotate
Rotate every page in a PDF and save the result as a new PDF.
PDF Page Delete
Remove selected pages and save the remaining pages as a new PDF.
PDF Page Reorder
Reorder, rotate, duplicate, or remove PDF pages, then save a new PDF.
PDF Watermark
PDF Preview
URL Parser
Break a URL into scheme, host, port, path, query, and fragment parts.
Query String Parser
Split a URL query string into keys, values, and duplicate parameters.
HTTP Request Builder
Common Port Lookup
HTTP Header Parser
Parse pasted HTTP request or response headers into structured fields.
CORS Header Checker
Inspect CORS origins, methods, credentials, and Vary settings.
MIME Type Lookup
Look up representative Content-Type values from extensions or MIME strings.
IP Address Analyzer
Validate IPv4, IPv6, and CIDR input and classify address ranges.
User-Agent Parser
Estimate browser, operating system, engine, and mobile state from a User-Agent.
MP3 to WAV
WAV to MP3
Audio Cutter
Audio Merge
Append multiple local audio files in order and save the result as WAV.
Volume Adjuster
Audio Format Info
Inspect local audio duration, decoded sample rate, channels, and peaks.
Silence Remover
Audio Speed Adjuster
Todo
Add tasks and organize them by list, date, and priority. Content is autosaved in this browser.
Kanban
Manage work cards across todo, doing, and done states locally.
Markdown Wiki
Save a Markdown document locally and preview it with an outline.
Bookmark Manager
Save URLs, titles, and tags in browser local storage, then filter them.
Habit Tracker
Memo Board
Project Notes
Focus Timer
Favicon Generator
SVG Optimizer
Clean pasted SVG by removing scripts, event attributes, unsafe content, and optional metadata.
CSS Box Shadow Generator
Adjust shadow position, blur, spread, and color, then copy the CSS.
CSS Gradient Generator
Build and preview a CSS gradient by editing color stops and direction.
Flexbox Playground
Preview Flexbox alignment and layout options in real time and copy the CSS.
CSS Grid Playground
Adjust columns, gaps, and item placement while previewing the CSS Grid result.
Border Radius Generator
Body Proportion Simulator
Compare entered body measurements and proportions in a 3D visualization.
ZIP Creator
Bundle selected local files into a browser-generated ZIP download.
ZIP Extractor
Open a selected ZIP in the browser and download individual files.
Archive Manifest Builder
Archive Path Sanitizer
Clean archive paths and flag absolute paths, traversal, backslashes, and duplicates.
TAR.GZ Viewer
Inspect file names and risky paths in a local TAR.GZ archive.
Compression Compare
Compare raw, gzip, and deflate sizes and ratios for text in the browser.
Archive Preview
Inspect ZIP names, dates, and risky paths before extraction.
File Hash Generator
Calculate SHA hashes for a local file in the browser. Files are not uploaded.
Hash Compare
Normalize whitespace and letter case, then compare two hash values.
SSH Key Generator
RSA Key Generator
Generate signing-oriented RSA public/private PEM keys with browser WebCrypto.
Checksum Viewer
Parse pasted checksum manifests into filenames, algorithms, and hash values.
Password Strength Checker
Check password length, character mix, and repeated patterns in the browser.
File Content Search
Regex File Search
Find lines matching a regular expression across selected local text files.
JSON Key Search
CSV Column Search
Find matching CSV headers and preview values from those columns.
Document Search Hub
Search multiple text documents and log files in one browser-only workspace.
File Splitter
Split a local file into downloadable parts of a specified size.
File Merge
Concatenate selected local files into one browser-generated download.
File Browser
Filter selected local files and preview part of a text file in the browser.
Batch File Rename
Preview new names for selected local files and copy a CSV rename plan.
File Info Viewer
CAD / 3D File Viewer
View STEP/STP, STL, 3MF, GLB, and common 2D DXF files locally in one browser workspace.
3MF Airflow Visualizer
Calendar Viewer
Generate a month calendar, mark the selected date, add local events, and export an ICS file.
Time Block Scheduler
Split a workday into focused time blocks with presets, breaks, and summary totals.
Recurring Schedule Generator
Generate recurring schedule dates, adjust weekends to weekdays, and export an ICS file.
Deadline Countdown
Calculate live days, hours, minutes, and seconds remaining until a deadline.
Nginx Log Viewer
Summarize pasted Nginx access logs by status code and request path in the browser.
Apache Log Viewer
Summarize pasted Apache combined logs by status code, client, and error request.
JSON Log Viewer
Parse JSON Lines or JSON array logs and summarize events by level.
CSV Log Analyzer
Parse CSV logs and summarize level, status, and time columns.
Roulette
Spin a browser-based roulette wheel for quick random choices.
Ladder Game
Create a simple ladder draw layout for teams, prizes, or assignments.
Draw Lots
Pick one or more winners from a list without sending data to a server.
Random Name Picker
Paste names and draw winners for class, event, or meeting use.
Random Team Generator
Random Order Generator
Random Number Generator
Generate fair random numbers with range, count, exclusions, and duplicate options.
Random Card Picker
Coin Flip
Dice Roller
Korean Age Calculator
D-Day Calculator
Count days remaining until a target date or days passed since an event.
Anniversary Calculator
Calculate 100-day, yearly, and custom anniversaries from a start date.
Military Discharge Calculator
Estimate discharge date, remaining days, and service progress from enlistment date.
Birthday Weekday Calculator
Zodiac Animal Calculator
Find the East Asian zodiac animal from a birth date or year.
Zodiac Sign Calculator
Lunar Solar Converter
Leap Year Calculator
Business Day Calculator
Count working days between dates with weekend and holiday options.
Discount Calculator
VAT Calculator
Compound Interest Calculator
Estimate compound interest growth from principal, recurring deposits, rate, and period.
Simple Interest Calculator
예금 이자 계산기
적금 계산기
대출 계산기
연봉 실수령액 계산기
퇴직금 계산기
시급 계산기
환율 계산기
BMI 계산기
기초대사량 계산기
하루 권장 칼로리
체지방률 계산기
물 섭취량 계산기
임신 주수 계산기
출산 예정일 계산기
Estimate expected delivery date from last period or conception date.
배란일 계산기
오늘의 운세
로또 번호 추천
MBTI 궁합
닉네임 생성기
별명 생성기
Open Graph 미리보기
Preview title, description, and share image metadata for messenger links.