Developer Tools

Essential tools for developers: code formatters, diff checkers, regex testers, API tools, and debugging utilities for efficient development workflow.

100 tools available

AI Tools 1

Prompt Token Budget Planner

100% on-device token budget planner: nothing leaves your browser. Estimate Claude, GPT, Gemini, Llama tokens and split prompts into RAG chunks with overlap.

Audio Tools 1

Text to Speech

Free text to speech with natural AI voices. Adjustable rate & pitch, word highlighting for proofreading, accessibility reader. Private, offline, no signup.

Blockchain Tools 5

Blockchain Timestamp Converter

Convert Unix timestamps (seconds or milliseconds) to dates and back for Ethereum, Bitcoin and EVM chains, with a Solidity duration calculator.

Keccak SHA3 Hasher

Free keccak256 online tool: compute 4-byte function selectors, event topic0 hashes, and EIP-55 checksum addresses. Keccak-256/512 and SHA3 in-browser.

ABI Encoder / Decoder

Decode Ethereum calldata and encode function calls online. Resolves unknown 4byte selectors, decodes tuples, structs, arrays and multicall on any EVM chain.

EVM Transaction Decoder

Decode EVM raw tx hex client-side: read the function selector and ERC-20 calldata, spot approval-drain phishing, and verify EIP-1559 gas before you sign.

Solidity Function Selector

Compute Solidity 4-byte function selectors (method ID) and 32-byte event topic hash via Keccak-256. Canonical signature normalization, calldata template, lookup.

Calculators 1

Math Calculators 1

Binary calculator

Binary calculator with selectable 8/16/32/64-bit width and signed/unsigned two's complement. Add, subtract, AND, OR, XOR, NOT, shift in any base.

Color Tools 7

Border Radius Generator

CSS border-radius generator with per-corner control, px/rem/em/% units, shorthand or longhand properties and live preview. Copy paste-ready CSS code.

Glassmorphism Generator

Create modern frosted glass UI effects with CSS backdrop-filter. Adjust blur, transparency, borders. 6 presets, live preview, copy production-ready code.

Flexbox Generator

Visual CSS Flexbox generator with live preview. Tune justify-content, align-items, gap and order, then copy production CSS (flex shorthand) plus matching HTML.

Box Shadow Generator

Box-shadow generator with live preview: multiple layers, inset, RGBA. Copy as CSS, Tailwind class, or React/JSX. Material elevation & neumorphism presets.

CSS Animation

Build CSS @keyframes animations visually. 11 presets, live preview, editable keyframe table, transform + opacity + color, copy production-ready CSS.

Clamp() Calculator

Free CSS clamp() calculator for fluid typography with rem/px output, CSS custom properties and Utopia-style type scales. Live preview plus a WCAG 1.4.4 zoom-safe check.

Cubic Bezier Editor

Free visual cubic-bezier editor for CSS animations. Drag handles to design easing curves, import an existing value, preview live, and copy the cubic-bezier().

Data Tools 5

Schema Extractor

Generate TypeScript, JSON Schema, Go, Python, Java and C# types from a JSON or CSV API response. Detects enums, optional and nullable fields. Free, private.

YAML-JSON Converter

Convert YAML to JSON and back, including multi-document Kubernetes manifests. Upload files or paste data; all processing stays in your browser.

JSON Tree Viewer

Explore JSON as a collapsible tree, run JSONPath queries, search keys/values, and see depth, size & key-count stats. Download filtered results. Free.

CSV-SQL Converter

Convert CSV to SQL INSERT and CREATE TABLE or SQL back to CSV in your browser. Pick MySQL, Postgres, SQLite or SQL Server dialect with batch multi-row inserts.

XML-JSON Converter

Convert XML to JSON and JSON to XML online, in your browser, no upload. Keeps attributes, CDATA, leading zeros and nested structures intact.

Developer Tools 66

Encoding 17

Base32 Encoder/Decoder

Encode or decode Base32 online per RFC 4648, with Base32hex and Crockford variants. Strict validation. Ideal for TOTP secrets, ULIDs and DNS.

Base58 Encoder/Decoder

Free online Base58 encoder/decoder. Decode Base58 strings, IPFS CIDs and raw bytes to hex or UTF-8 text, and encode text or hex (Bitcoin alphabet).

Base64 Encoder/Decoder

Free Base64 encoder & decoder. Encode text or files, generate data: URIs, decode Base64URL/JWT, UTF-8 & MIME line wrapping. Fast, private, browser-based.

Base85 Encoder/Decoder

Encode text or binary to Base85 (Ascii85) and decode back instantly. 25% more compact than Base64, perfect for PDF, PostScript and Git pack files.

Bcrypt Hash Generator

Generate bcrypt hashes online with selectable cost factor (4 to 14 rounds). Verify $2a, $2b, $2y hashes and audit cost to see if a hash needs rehashing.

HMAC Generator

Generate and verify HMAC signatures (SHA256/SHA512/SHA1/MD5). Compare webhook signatures, sign AWS requests and JWT HS256. Hex or Base64, 100% browser.

HTML Entities Encoder/Decoder

Escape HTML or decode entities online. Named, numeric & hex forms, code-point inspector, OWASP context-aware escaping — a free htmlspecialchars equivalent.

Hex Encoder/Decoder

Text ⇄ hex converter — plain, 0x-prefixed, space-separated, upper/lowercase. Auto-detects on decode, handles UTF-8. For debugging, memory dumps, colors.

Image Base64 Encoder/Decoder

Encode images to Base64 data URIs that preserve the original format and MIME with no quality loss, or decode Base64 to PNG/JPG. Client-side, no upload.

JWT Encoder/Decoder

Decode JWTs and verify HMAC signatures (HS256/384/512) in-browser. Inspect header, payload, claims, and validate exp, nbf, and iat. Build and sign tokens too.

MD5 Hash Generator

Free MD5 hash generator and checksum verifier. Generate an MD5 from text and paste an expected MD5 to verify downloads — instant MATCH or MISMATCH.

Morse Code Translator

Translate text to International Morse code and back with audio at adjustable WPM, tone Hz and Farnsworth timing. Letters, numbers, punctuation, @ and prosigns.

Punycode Converter

Convert Unicode domains (IDN) to ASCII Punycode and back per RFC 3492. IDNA2008 / UTS-46 NFC normalization, xn-- ACE label, mixed-script warning.

SHA-1 Hash Generator

Generate a SHA-1 hash from text or a file and verify it against a published SHA1SUM checksum. Match/no-match verdict, runs locally via Web Crypto.

SHA-256 Hash Generator

Generate a SHA-256 hash from text or a file. Verify downloads against a published checksum without uploading the file. Runs locally via Web Crypto.

SHA-512 Hash Generator

Generate a SHA-512 hash from text or a file, then verify it against a published checksum. Runs 100% locally via Web Crypto — nothing is uploaded.

URL Encoder/Decoder

Free URL encoder/decoder with encodeURIComponent vs encodeURI and RFC 3986 strict mode for OAuth and AWS SigV4 canonical requests. Decode preserves literal +.

Formatter & Minifier 10

CSS Formatter & Minifier

Prettier-powered CSS formatter and minifier. Beautify or compress stylesheets 100% in your browser and see exact bytes saved, percent reduction and gzip size.

HTML Formatter & Minifier

Prettify, minify and validate HTML online. Collapse whitespace for production, preserve <pre>/<script>, get W3C-style indentation and unclosed-tag checks.

JSON Formatter & Minifier

Format, minify and validate JSON with a collapsible tree, JSONPath query, duplicate-key detection and line/column error location. RFC 8259 strict.

JavaScript Formatter & Minifier

JavaScript formatter and minifier powered by Prettier with live syntax validation and size-reduction readout. Runs locally, supports ES6+, async/await.

Markdown Formatter

Format Markdown and generate a GitHub-compatible table of contents with anchor links. Normalise headings, list markers, spacing; live HTML preview.

PHP Formatter & Minifier

Free online PHP formatter, beautifier, minifier and PSR-12 / PER-CS compliance checker. Runs 100% in your browser, so private code never leaves your machine.

Python Formatter & Minifier

Browser-side Python formatter, minifier and PEP 8 checker: normalise indentation, add blank lines, highlight syntax and flag style issues with line numbers.

SQL Formatter & Minifier

Format, beautify and safely minify SQL across 15 dialects (BigQuery, Snowflake, Redshift, T-SQL, PostgreSQL). Safety lint flags UPDATE/DELETE with no WHERE.

XML Formatter & Minifier

Format, minify, validate and run XPath on XML online: SOAP, SVG, RSS/Atom, XSD/XSLT, Maven POM, sitemaps and Spring/Android config, with CDATA-safe minify.

YAML Formatter & Minifier

Free online YAML formatter, minifier and validator. Beautify or minify YAML and validate syntax with exact error line and column for Kubernetes, Docker.

Generators 14

Redirection Rules Generator

Build redirect rules for Apache .htaccess, Nginx, Netlify _redirects — 301/302/307/308. Wildcard path-forwarding, bulk 301 import, syntax-correct output.

TOTP Generator

Free online TOTP / 2FA code generator and verifier (RFC 6238). Paste a Base32 secret to see live codes, scan the QR with any authenticator, and verify codes.

.htaccess Generator

Free .htaccess generator: force HTTPS, WWW/non-WWW redirects with your real domain, GZIP, caching, bot blocking, Apache 2.4 security and custom 301 rules.

Cron Expression Generator

Build, parse and validate crontab and Quartz cron expressions. Paste any line or @daily macro, expand it, see human-readable text and next run times.

Favicon Generator

Generate a real multi-size .ico plus PNG, apple-touch-icon and a custom site.webmanifest with theme color from one image. Free PWA favicon maker.

JSON-LD Generator

Free, no sign-up JSON-LD generator. Validates Google-required fields and copy-paste a <script> for rich results across 12 schema types, fully client-side.

Manifest Generator

Build a Web App Manifest and audit PWA installability live: checks 192/512 PNG and maskable icons so your app passes Lighthouse and shows the install prompt.

Meta Tag Generator

Generate spec-compliant HTML meta tags for SEO, Open Graph and Twitter Cards with a live SERP and social preview plus pass/warn/fail validation. No signup.

Regex Generator

Visual regex builder + live tester: highlight matches, capture groups, lookahead, replace preview, export valid JS/Python/PHP/Java/Ruby/Go code. No install.

Robots.txt Generator

Build a robots.txt with a live URL tester and an RFC 9309 (Robots Exclusion Protocol) compliance linter. WordPress, e-commerce & blog presets included.

Sitemap Generator

Build sitemap.xml with lastmod, changefreq and priority. Auto-splits past the 50,000-URL limit into a sitemap index, validates, ready for Search Console.

UUID Batch Generator

Generate up to 10,000 UUIDs: random v4, time-ordered v7, deterministic name-based v5 (namespace + name). Export TXT, CSV, JSON or SQL INSERT.

UUID Generator

Generate UUID v1, v4, v5, v7 and Nil GUID with crypto.randomUUID. Bulk up to 100, uppercase, hyphens, braces, RFC 4122 / 9562 compliant.

WiFi QR Generator

Generate branded WiFi QR codes with your logo and colors. Scan to auto-connect — no typing. WPA3/WPA2/WEP, open and hidden networks, scannability check.

Testing & Debugging 7

HTML Previewer

Run HTML, CSS and JavaScript online with live preview, real console errors, responsive device widths and CDN libraries. Sandboxed, free, no signup.

WebSocket Tester

Connect to any ws:// or wss:// endpoint, send/receive messages live, see full history with timestamps. For debugging chat, GraphQL subs, MQTT-over-WS.

API Request Tester

Browser REST client: GET/POST/PUT/PATCH/DELETE, custom headers, JSON body, response timing, and one-click Copy as cURL. Free Postman-lite tester.

HTTP Header Viewer

HTTP header viewer with a security header scorecard: get an A+ to F grade for HSTS, CSP, X-Frame-Options, CORS, plus your own request headers.

C Sandbox

Online C sandbox — compile and run C with GCC 10.2 in your browser. Pick C89/C99/C11/C17, toggle -Werror, add flags (-Wall -O2 -lm), feed stdin. Zero install.

Python Sandbox

Run Python 3 in your browser via Pyodide (CPython on WebAssembly). Full stdlib, pip via micropip, persistent session, offline after first load. Zero install.

Regex Tester

Free online regex tester with live matching, named capture groups, lookahead/lookbehind, and a replace/substitution mode using $1 and $<name> tokens.

Utilities 18

Google Fonts Pair Finder

Find and preview Google Fonts pairings, then export production-ready code: CDN, GDPR-safe self-host @font-face, preload links, variable fonts.

URL Slug Generator

Bulk URL slug generator: convert text to clean SEO slugs with accent transliteration. Batch mode makes one de-duplicated slug per line for CMS migrations.

WHOIS Lookup

WHOIS / RDAP domain lookup with expiry countdown — registrar, days until expiry, domain age, nameservers, EPP status codes, DNSSEC. 1500+ TLDs, no API key.

Robots.txt Tester

Test robots.txt rules with RFC 9309 group selection and Allow/Disallow precedence. Bulk-check URLs per bot, export CSV. Blocking is not deindexing.

User-Agent Parser

Decode any User-Agent string — browser, version, OS, device, engine, bot. Auto-fills your own UA. For analytics, QA, and bot triage.

CSS Specificity

Compute CSS specificity for any selector with a color-coded breakdown, multi-selector comparison, and a source-order tiebreaker for specificity ties.

HTML to JSX

Free online HTML to JSX converter for React. Renames class→className, for→htmlFor, builds style objects, self-closes void elements, outputs typed .tsx.

HTTP Status Codes

Complete HTTP status code reference. Search 60+ codes (100–511) with definitions, RFC links, cacheable & retryable flags. Covers 200, 301, 404, 429, 500.

Mermaid Editor

Free Mermaid live editor for UML, flowcharts, class & ER diagrams. No install, renders live, exports PNG/SVG with transparent background and 1x-4x scale.

Subnet Calculator

Free IPv4 subnet calculator with CIDR to subnet mask, Cisco wildcard mask, VLSM splitting, binary view, and reverse host sizing (pick the prefix for N hosts).

AI Context Bundler

Bypass the context window: split long code, docs or transcripts into model-aware numbered chunks for Claude, GPT, Gemini or Llama, then download all at once.

Cron Expression Parser

Free Cron Expression Parser: explain Unix, Linux & Quartz cron in plain English, preview next run times by timezone, and decode @daily, @reboot macros.

Diceware passphrase generator

Free Diceware passphrase generator using the EFF long wordlist and WebCrypto. Pick word count, separator, see entropy bits and crack-time estimates.

JSON to TypeScript

Free online JSON to TypeScript converter. Paste any JSON, get strict interfaces with nested objects, arrays, and string-literal unions. Private, in-browser.

JavaScript Obfuscator

Free private JavaScript obfuscator. 100% browser-side, with presets, control-flow flattening, string-array encoding, Node.js target and reproducible seed.

Markdown cheatsheet

Searchable Markdown cheatsheet with live preview and copy-paste snippets for README files: headings, tables, task lists, links, code, callouts and math.

OpenAPI Spec Validator

Validate an OpenAPI 3.x JSON or YAML spec online: lint structure, summarize endpoints, detect broken $ref, catch missing 401/403 and undeclared params. Free.

cURL to Code

Convert curl to fetch, Python, PHP, Node, Java, C# and more. Paste a Chrome DevTools 'Copy as cURL' and redact API keys in one click. Client-side.

File Tools 1

File Compare

Compare two text, code, JSON or CSV files line by line with syntax highlighting. Ignore whitespace, case or CRLF/LF. 100% in-browser, no upload.

Fun Tools 5

Fake Android Update

Free online fake Android system update screen generator with Pixel, Samsung, Stock and Bootloader themes. No install. Fullscreen prank, tap or ESC to exit.

Fake Virus Scan

Free fake virus scan prank that runs 100% in your browser — no download, totally safe. Norton, McAfee and Avast themes with one-tap exit on any device.

Fake XP BSOD

Generate the classic Windows XP Blue Screen of Death. Custom STOP code, driver and memory dump. Tap or ESC to exit. Free, offline, mobile-friendly.

Fake iOS Update

Free fake iOS update screen, no download. Realistic iPhone Apple logo and progress ring. Custom version and speed. Tap or press ESC to exit anytime.

Fake macOS Update

Free online fake macOS update screen (Sonoma, Ventura, Recovery). Fullscreen prank with Apple logo and progress bar. Tap twice or ESC to exit. Safe.

Hardware Tools 1

Connectivity 1

USB Device Viewer

Browser-based USB descriptor inspector via WebUSB. No drivers, no install — read VID/PID, configs, interfaces & endpoints in Chrome/Edge. lsusb alternative.

Image Tools 2

Barcode Generator

Generate Code128, EAN-13, EAN-8, UPC-A, Code39, ITF-14, MSI and Pharmacode barcodes with live GS1 check-digit verification. Download SVG or PNG in browser.

QR code decoder

Free QR code decoder and payload parser. Inspect a QR's link and host before clicking to avoid quishing, and read Wi-Fi, vCard and OTP fields locally.

Time Tools 1

ISO Date Converter

Convert ISO 8601 to Unix epoch, RFC 3339, SQL DATETIME, week date and ordinal date with 4 simultaneous timezones, relative time, and Excel/Julian serials.