69

npm Version Range Checker - Online SemVer & Tilde Caret

Enter a package name and version range to see all satisfying versions from the registry. Understand ^ and ~.

Developer Tools checker npm range semver

59

ASCII Table - Online Character Code Reference

Interactive ASCII table showing decimal, hex, octal, and binary codes for all standard and extended ASCII characters. A classic programmer reference.

Developer Tools ASCII character code reference table

48

PWA Install Prompt Checker - Online See beforeinstallprompt Status

Check if the browser has captured the beforeinstallprompt event. Understand why your PWA is (or isn't) installable.

Developer Tools checker install prompt PWA

47

Clipboard API Tester - Online Read & Write Sandbox

Experiment with the Async Clipboard API: read/write text and images from the clipboard. Verify permissions and see demo code.

API API Clipboard copy paste

46

Font Fallback Checker - Online See Missing Glyphs

Type any character and see how it renders in different font stacks. Detect missing glyphs and fallback behavior.

Design checker fallback font typography

45

Browser Storage Quota Estimator - Online Check Limit

Estimate how many MB/GB your storage can hold based on navigator.storage.estimate() and display as a pie chart.

Developer Tools estimator IndexedDB quota storage

44

Dynamic Placeholder Image Service - Online Test Images

Generate dynamic placeholder images by specifying width, height, colors, and text. View instantly as a URL you can embed in mockups. Canvas-based.

Developer Tools dynamic image mockup placeholder

44

GraphQL Playground - Online Query & Schema Explorer

Execute GraphQL queries against any endpoint with variables and headers. Explore schema via introspection. All requests made directly from your browser.

API API GraphQL query schema

43

JSON to Graph Visualization - Online Tree Diagram

Paste a JSON object and see a dynamic, draggable tree graph representation. Excellent for debugging nested data.

Developer Tools graph JSON tree visualizer

42

SQL Formatter & Beautifier - Online SQL Query Cleaner

Format and beautify SQL queries for improved readability. Supports various SQL dialects. Quick syntax highlighting and local processing ensure a secure experience.

Developer Tools beautifier formatter query SQL

42

JSON Formatter & Validator - Online JSON Beautifier

Online JSON formatting and validation tool, supporting JSON minify/beautify, syntax highlighting, and error locating. Data processed locally in browser for security.

Developer Tools beautify formatter JSON validator

41

File MIME Type & Magic Bytes Detector - Online

Drop a file to see its MIME type and the first few magic bytes (hex and ASCII). No upload, works instantly.

Developer Tools detector file magic bytes MIME

40

Gray Code Converter - Online Binary to Reflected Code

Translate between binary and Gray code (reflected binary code). See the bit changes. Useful for digital logic.

Converter binary converter Gray code logic

40

Crontab Expression Editor - Online Interactive Cron Builder

Build cron expressions using a visual editor with dropdowns. See human-readable description and next run times. Easier than raw cron.

Developer Tools cron crontab editor scheduler

40

Code Screenshot Generator - Online Carbon Code Image Maker

Create beautiful, syntax-highlighted screenshots of your code snippets. Choose themes and export as PNG. All client-side canvas rendering.

Developer Tools code screenshot image share syntax

40

Responsive Design Tester - Online Viewport Emulator

Preview any website inside emulated device viewports (iPhone, iPad, various resolutions). No screenshot, live interaction in an iframe. Local tool.

Design emulator mobile responsive test viewport

40

XML Formatter & Validator - Free Online XML Beautifier

Easily format, validate, and beautify XML documents. Minify XML data with a single click. All processing happens locally in your browser for maximum privacy.

Developer Tools beautify formatter validator XML

39

Promise State Viewer - Online Check Resolve & Reject

Create promises that resolve or reject after a delay. See state changes and chain .then/.catch. Debug async code.

Developer Tools async JavaScript Promise state

39

Text Decoration CSS Generator - Online Underline & Strike

Style underlines, overlines, and strike-throughs with colors, wavy styles, and thickness. Modern CSS text‑decoration.

Developer Tools CSS generator text decoration underline

39

Emoji Favicon Maker - Online Convert Emoji to .ico

Pick an emoji and convert it into a proper favicon .ico file for your website. No design skills needed. Instant download.

Developer Tools emoji favicon generator .ico

39

Bit Density Visualizer - Online File Binary Viewer

Upload a small file to see each byte as a block, color-coded by value. Visualize the structure of binary data. Client-side.

Developer Tools binary bits file visualizer

39

Decimal to IEEE 754 Converter - Online Float Representation

Convert a decimal number to 32-bit single precision IEEE 754 format. See sign, exponent, mantissa bits. Developer tool.

Converter binary converter float IEEE 754

39

File Encoding Checker - Online Detect Text File Charset

Upload a text file to detect its character encoding (UTF-8, ISO-8859-1, etc.) and BOM presence. Runs entirely in your browser.

Developer Tools charset detector file encoding UTF-8

39

JSON to CSV Converter - Online Free Data Translator

Easily convert JSON data arrays into CSV format for Excel or database import. Handles nested structures with flattening options. All conversions happen locally, no data uploaded.

Converter converter data JSON to CSV spreadsheet

39

RegEx Tester - Online Regular Expression Builder & Matcher

Build and test regular expressions against sample text. Real-time match highlighting, capture groups display, and flavor options. All inside your browser.

Developer Tools builder regex regular expression tester

39

Border Radius CSS Generator - Online Rounded Corners Tool

Easily create asymmetric border radius values and preview the result. Copy the generated CSS instantly. All interactively and browser-based.

Developer Tools border radius CSS design generator

38

Responsive Image CSS - Online Art Direction & Srcset

Upload an image at multiple widths and generate a complete <picture> or <img srcset> snippet. Modern web performance.

Developer Tools images picture responsive srcset

38

Custom Scrollbar CSS Generator - Online Firefox & Webkit

Design a fully styled scrollbar with colors, width, radius, and hover effects. Supports both ::-webkit‑scrollbar and Firefox scrollbar‑width.

Developer Tools CSS custom generator scrollbar

38

CSS Letterpress Text Effect - Online Inset Typography

Create a realistic letterpress (debossed) text effect using CSS text‑shadow and background. Adjust depth and light direction. Copy code.

Developer Tools CSS generator letterpress text

38

Test Credit Card Validator - Online Luhn Check & Issuer

Paste a test card number to verify Luhn algorithm, identify issuer (Visa, MC), and check length. No real data.

Developer Tools credit card Luhn test validator

38

Image to CSS Grid Layout - Online Pixel‑Based Generator

Upload a small pixel art image and get a CSS grid layout that recreates it using divs. Novelty developer tool.

Developer Tools CSS grid generator image pixel

38

Swagger/OpenAPI YAML Previewer - Online Render & Test

Paste your Swagger/OpenAPI YAML and see a rendered API documentation preview with expandable endpoints. All local rendering.

API OpenAPI preview Swagger YAML

38

Signed Magnitude Converter - Online Negative Binary Numbers

Encode decimal integers into signed magnitude binary representation and decode back. Learn computer arithmetic.

Developer Tools binary converter negative signed magnitude

38

PRNG Validator - Online Check Randomness Pattern

Paste a list of numbers to visually check uniformity, mean, and simple pattern analysis. Educational tool for statistics and RNG.

Developer Tools PRNG random statistics validator

38

Gradient Text CSS Generator - Online Colorful Text Style

Create text with a gradient fill using CSS background-clip. Configure colors and direction. Copy the code. Works in modern browsers.

Developer Tools colorful CSS generator gradient text

38

Flexbox Playground - Online CSS Flex Layout Generator

Visually experiment with Flexbox container and item properties. See the layout update in real time and copy the CSS. Learn by doing, fully interactive.

Developer Tools CSS Flexbox layout playground

38

Online Hash Generator - MD5 SHA1 SHA256 CRC32 Checksum

Generate cryptographic and checksum hashes for any text string. Supports MD5, SHA-1, SHA-256, and CRC32. All hashing runs locally for maximum privacy.

Developer Tools checksum hash MD5 SHA256

38

Text Diff Checker - Online Compare & Find Differences

Compare two text blocks and highlight differences line by line. Ideal for code review and document revisions. All diffs computed locally for privacy.

Developer Tools code compare diff checker text difference

37

CSS Scroll Snap Generator - Online Visual Builder

Visually configure scroll‑snap containers and items. Adjust alignment, stop behavior, and padding. Copy the clean CSS instantly.

Developer Tools carousel CSS generator scroll snap

37

MD5 Hash Generator - Online Quick Checksum

Generate the MD5 hash of any text string. For quick integrity checks. All local computation.

Developer Tools checksum generator hash MD5

37

Advanced CSS Gradient Builder - Online Multi‑Stop & Angle

Create complex linear gradients with any number of color stops, exact angles, and length units. Live preview and CSS code.

Developer Tools angle builder CSS gradient

37

HTTP Request Composer - Online Build & Send Requests

Pick a method, URL, headers, and body, then send an HTTP request directly from your browser. Debug APIs easily.

API API HTTP request test

37

HTML Minifier - Online Compress Web Pages

Reduce your HTML file size by stripping whitespace, comments, and optional closing tags. Secure browser‑based.

Developer Tools compress HTML minifier size

37

Batch Image to Base64 Encoder - Online Multiple Files

Convert multiple images to Base64 data URIs at once. Copy individually or as a JSON array. Great for inline assets. Local.

Developer Tools Base64 batch data URI image

37

Regex Visualizer - Online Railroad Diagram Generator

Enter a regular expression and see a visual railroad diagram explaining the pattern. Learn and debug regex.

Developer Tools debug diagram regex visualizer

37

Focus Order Analyzer - Online Tab Navigation Check

Enter a URL and extract tab‐index order violations and focusable elements. Quick accessibility audit. Client‑side fetch.

Accessibility accessibility focus keyboard tabindex

37

Gradient Match Game - Online Drag & Match Linear CSS

Recreate the target CSS linear gradient by adjusting stops and colors. A unique game for front‑end developers to master gradients.

Developer Tools CSS game gradient match

37

Favicon Converter - Online Image to .ico & Multi-size

Upload a logo and generate a pack of favicon sizes plus a .ico file. All conversion in your browser.

Developer Tools converter favicon .ico website

37

SQL JOIN Visualizer - Online Interactive Venn Diagrams

See interactive Venn diagrams for SQL JOINs: INNER, LEFT, RIGHT, FULL, CROSS. Understand set theory visually. Local static site.

Developer Tools JOIN SQL Venn visualizer

37

Git Cheatsheet - Online Common Commands Reference

Quick reference for frequently used Git commands with examples. Searchable and categorized. A handy resource for all developers.

Developer Tools cheatsheet commands Git reference

37

HTTP Headers Checker - Online Inspect URL Response Headers

Enter a URL and see the full HTTP response headers returned by the server. Detect redirects and server type. Useful for SEO and web debugging.

Developer Tools checker HTTP headers response server

37

Number Base Converter - Online Binary Octal Decimal Hex

Convert numbers between binary, octal, decimal, and hexadecimal bases. See real-time conversion as you type. Clean and simple programmer utility.

Converter binary converter hex number base

37

JavaScript Keycode Finder - Online Keyboard Event Tool

Press any key to see the corresponding JavaScript event key, code, and keyCode. An essential debugging tool for front-end developers handling keyboard input.

Developer Tools event JavaScript keyboard keycode

37

Online Code Minifier - JS & CSS Compression Tool

Minify JavaScript and CSS code to reduce file size for production. Remove whitespace and comments instantly. Run locally, your code stays private.

Developer Tools compress CSS JavaScript minifier

37

Crontab Guru - Online Cron Expression Parser & Translator

Describe cron schedule expressions in plain English and test future execution times. Indispensable for DevOps and backend developers. Local analysis.

Developer Tools cron expression parser schedule

37

Markdown Previewer - Online Live MD to HTML Renderer

Write Markdown and see the formatted HTML preview in real time. Syntax highlighting and GitHub-flavored Markdown support. No upload, fully local.

Developer Tools HTML Markdown MD previewer

37

HTML Formatter & Beautifier - Online HTML Cleaner

Tidy up messy HTML code with our online formatter and beautifier. Indent and clean your markup, preview the output instantly. No data is uploaded, everything runs in your browser.

Developer Tools beautifier cleaner formatter HTML

36

Mailto Link Generator - Online HTML Email Link

Build a complex mailto: link with to, cc, bcc, subject, and body. Get the HTML anchor tag. Local.

Developer Tools email generator HTML mailto

36

Mix‑Blend‑Mode Playground - Online CSS Effect Tester

Pick two images or colors and apply all 16 CSS mix‑blend‑mode values live. See and copy the right CSS for your design.

Color Tool CSS mix-blend-mode overlay playground

36

CSS Checkerboard Pattern - Online Background Generator

Create a customizable checkerboard or grid background using pure CSS gradients. Adjust cell size and colors. Copy the code.

Developer Tools checkerboard CSS generator pattern