Marcus Webb
"The DevTool Craftsman"
Full-Stack Developer & Tools Architect
Marcus has been writing code since the dial-up era. He's contributed to open-source developer tools, built CI/CD pipelines for startups, and debugged production incidents at 3 AM more times than he'd like to admit. His philosophy: the best developer tool is the one that gets out of your way.
143 tools by Marcus
HTML Editor (WYSIWYG) — A simple in-browser WYSIWYG editor — format with the toolbar, paste rich text from Word or web pages, and copy the resulting HTML.
JSON Formatter / Validator — Format, minify, or validate any JSON in your browser. Choose indent style and see error details for invalid input.
Markdown to HTML — Convert Markdown to HTML with live side-by-side preview. Supports headings, lists, links, images, code blocks, blockquotes, and empha...
Text Diff / Compare — Compare two blocks of text and see exactly what changed — added lines in green, deleted in red, unchanged in gray.
JWT Decoder — Paste a JWT and see the header, payload, expiry, and signature parts decoded. Everything happens in your browser.
CSV ↔ JSON — Convert tabular data between CSV and JSON. Header row detection, custom delimiter, quoted-field-with-comma support.
Regex Tester — Test JavaScript regular expressions live — see matches highlighted in your text and captured groups in a list.
Color Converter — Convert between HEX, RGB, HSL, and RGBA — pick a color or type any format and the others update live.
Number Base Converter — Convert numbers between decimal, hex, binary, octal — or any arbitrary base from 2 to 36.
JSON Diff — Compare two JSON values structurally — see exactly what was added, removed, or changed, with full key paths.
Cron Expression Builder — Edit a 5-field cron expression and see plain-English description plus the next 5 fire times in your local timezone.
Meta Tag Generator — Generate SEO meta tags, Open Graph tags, and Twitter Card tags for any page — with a live Google search-result preview and length w...
Color Palette Generator — Pick a base color and generate a harmony palette — complementary, analogous, triadic, tetradic, split-complementary, monochrom...
CSS Gradient Generator — Build linear, radial, or conic CSS gradients visually. Add unlimited color stops, drag the angle, see the live preview, and cop...
Box Shadow Generator — Build CSS box-shadow visually — tune offset, blur, spread, color, opacity, and inset with live preview.
Markdown Table Generator — Build Markdown tables with a visual cell editor — set rows/columns, click to edit any cell, pick alignment, or import from CSV.
Color Contrast Checker — Pick a foreground and background color and instantly see the WCAG 2.1 contrast ratio with pass/fail badges for AA and AAA, norm...
SQL Formatter — Paste any SQL query and get it formatted with proper indentation, keyword casing, and clause breaks. Supports 10 dialects including Post...
YAML Formatter — Paste any YAML and format it cleanly — pick indent width and line wrap, optionally sort keys. Also validates YAML syntax and converts b...
JSON to TypeScript — Paste a JSON payload and instantly get TypeScript interfaces (or type aliases) describing its shape. Optionally mark all properties...
Cron Visualizer — Paste any 5-field cron expression and instantly see: a plain-English description, a field-by-field breakdown, and the next 10 schedule...
GitHub Badge Maker — Generate Shields.io-style SVG badges for any GitHub README. Pick label, value, colors and one of four styles (flat, flat-square, fo...
JWT Encoder / Signer — Build and sign a JWT — pick HS256 / HS384 / HS512, paste a header and payload (JSON), provide your secret, get a signed token. Us...
MIME Type Lookup — Type a file extension (or filename) and get the proper <code>Content-Type</code> header value. Reverse lookup too — type a MIME type ...
JSON to Go Struct — Paste a JSON sample and get matching Go struct definitions — with optional <code>json:"..."</code> tags, <code>omitempty</code>, and...
JSON to JSON Schema — Paste any JSON sample and get a JSON Schema describing its shape — useful for API documentation, request/response validation, and ...
JSON to Zod Schema — Paste JSON and get a ready-to-use <code>z.object({...})</code> Zod schema plus the inferred TypeScript type.
HTML to Markdown Converter — Paste any HTML snippet — from a blog post, a CMS export, or a webpage — and get clean Markdown ready for static site genera...
Pick any color and get its HEX, RGB, HSL, and HSV values instantly. Free online color picker with eyedropper and color harmony.
.htaccess Generator — Generate .htaccess rules for common Apache web server configurations — redirects, caching, password protection, hotlink blocking, ...
Minify CSS code online. Remove comments, whitespace, and unnecessary characters to reduce file size. Free CSS minifier — instant results.
Minify HTML code online. Remove comments, collapse whitespace, and reduce file size. Free HTML minifier — instant results in your browser.
Parse any URL into its components: protocol, hostname, port, path, query parameters, and hash. Free online URL parser tool.
Parse user agent strings to identify browser, operating system, and device type. Free online user agent parser with instant results.
QR Code Reader — Upload a QR code image to decode its contents. Supports drag-and-drop, file upload, and clipboard paste. Extracts URLs, text, and other...
MIME Type Checker — Enter a file extension or MIME type to look up the corresponding type. Supports 160+ common file formats including web, office, medi...
JavaScript Minifier — Paste your JavaScript code to minify it instantly. Removes comments, collapses whitespace, strips console.log and debugger stateme...
RGB to HEX Converter — Convert between RGB, HEX, HSL, and RGBA color formats with a live color preview. Enter a value in any format and see all conversi...
Generate HTML table markup from delimited text data. Supports tab, comma, CSV, and custom delimiters. Free online HTML table generator.
Barcode Reader — Upload an image containing a barcode or QR code to instantly decode its content. Supports multiple barcode formats.
Free online file MIME type checker. Upload any file to detect its MIME type, file extension, description, and size.
Text Compare — Compare two texts side-by-side to highlight line and character differences. Ideal for developers, writers, and editors.
Code Diff & Merge — Compare two code snippets side-by-side. View additions and deletions with syntax highlighting, and merge changes interactively with ...
Data Format Converter — Convert between structured data formats instantly. Parse and serialize JSON, YAML, TOML, and XML with configurable indentation a...
JSON Schema Builder — Build JSON validation models visually. Configure properties, toggle required attributes, and instantly copy JSON Schema, Zod code,...
Regex Explainer — Deconstruct regular expressions. Analyze quantifiers, capture groups, sets, boundaries, and flags with clear explanations.
Base64 Inspector — Analyze and validate Base64 content. Inspect MIME headers, calculate overhead size, preview file assets, and download decoded binary ...
SQLite Studio & Viewer — Explore, query, and convert SQLite databases in your browser. Runs entirely client-side using WebAssembly database execution.
Free online code minifier. Compress HTML, CSS, and JavaScript code instantly in one place. Removes comments, whitespace, and formatting to optimize speed.
Generate JSON-LD structured data for Article, Product, LocalBusiness, FAQPage, Organization, BreadcrumbList, and Event schema types instantly.
Paste your URLs and generate a valid XML sitemap with changefreq, priority, and lastmod. Download sitemap.xml instantly — no signup needed.
Visually craft CSS border-radius — independent corners, px/%/em units, and organic blob shapes. Live preview and copy-paste CSS. Runs in your browser.
Design frosted-glass CSS with live preview — blur, saturation, fill opacity, border and shadow. Copy backdrop-filter CSS. Runs in your browser.
Create CSS clip-path shapes visually — polygons, circles, insets and 20+ presets with draggable points. Live preview and copy-paste CSS, in your browser.
Design CSS cubic-bezier easing curves with a draggable editor, presets, and a live animation preview. Copy the timing-function CSS, all in your browser.
Design CSS text-shadow visually — stack multiple layers, pick neon, 3D, outline and retro presets, then copy the CSS. Live preview, runs in your browser.
Build soft-UI neumorphism CSS visually — base color, light direction, shape and shadow distance. Copy box-shadow CSS. Live preview in your browser.
Make CSS triangles with the border trick — choose direction, width, height and color, preview live, and copy the width/height/border CSS. Runs in browser.
Visually build a CSS filter — blur, brightness, contrast, grayscale, hue, sepia and drop-shadow — preview on your own image and copy the CSS. In-browser.
Build CSS transforms visually — translate, scale, rotate, skew plus 3D rotateX/Y/Z and perspective. Live preview on a grid and copy the CSS, in-browser.
Build CSS @keyframes animations — fade, slide, bounce, pulse, spin, flip, zoom — tune duration, easing, delay and loop, preview live and copy the CSS.
A visual CSS flexbox playground — tweak direction, justify, align, wrap and gap, watch the live preview, and copy the container CSS. Runs in your browser.
A visual CSS grid playground — set columns, rows, gaps and track sizing, watch the live preview, and copy the generated grid CSS. Runs in your browser.
Design a CSS button visually — padding, colors, gradients, border-radius, shadow and hover effects — with a live preview, then copy the CSS. In-browser.
Style custom scrollbars visually — width, track and thumb colours, hover and radius — with a live WebKit preview and Firefox fallback. Copy the CSS.
Calculate file or text hashes online — MD5, SHA-1, SHA-256, SHA-512. Verify file integrity by comparing a known checksum. Free, in your browser.
Inspect a PDF's internal structure as formatted JSON. See objects, streams, cross-reference tables, and page trees. Developer tool, in-browser.
Free online monitor test: solid colors, gradients, grid patterns. Find dead pixels, check backlight bleed, test screen uniformity — all in your browser.
Free dead pixel test: full-screen solid colors to find stuck or dead pixels on any monitor, phone, or tablet. No download — runs in your browser.
Screen uniformity test: check for backlight bleed, uneven brightness, and color shifts. Full-screen gray and color patterns for any monitor or display.
Write HTML, CSS, JS in tabbed editors with live iframe preview. Auto-run, download as HTML file. Preloaded counter app sample. No server — pure browser.
Free monitor response time test with flying square UFO ghosting and pursuit camera bar patterns. Measure pixel response and see ghosting on your display.
Monitor viewing angle test with colored wedges and grayscale ramp. Detect color shifts, brightness drop-off, and IPS glow on your display.
Simulate protanopia, deuteranopia, tritanopia, and achromatopsia color blindness on images. Upload a photo or use the built-in test pattern.
Calculate and compare CSS selector specificity instantly. See (a,b,c) breakdown, visualize with bar charts, and find which selector wins. Free developer tool.
Paste SVG path data and see it rendered live. View control points for bezier curves. Supports all path commands (M, C, S, Q, T, A, Z). Free developer tool.
Interactive searchable reference for all HTTP status codes (1xx-5xx). Click to copy, filter by category. Free developer tool, no signup.
Free online Markdown editor with live preview, toolbar, GFM tables, RTL direction support for Arabic, Persian, Urdu, Hebrew. Download as HTML or Markdown. No signup.
Free online css unit converter. No signup, no upload — works entirely in your browser. Fast, private, and free forever.
Free online api tester. No signup, no upload — works entirely in your browser. Fast, private, and free forever.
Free online json toolkit. No signup required.
Generate pure CSS loading spinners, dots, pulses, bars, rings and more. Customize colors, size, and speed. Copy CSS + HTML instantly.
Design custom CSS checkboxes with tick, cross, fill, or minus styles. Control size, colors, border radius. Live preview and copy CSS.
Design custom CSS toggle switches. Control width, height, on/off colors, knob size, animation speed, and labels. Live preview and copy code.
Create cyberpunk-style CSS glitch text effects. Control intensity, cyan/magenta shift colors, animation speed, and skew. Live preview and copy CSS.
Free online IPv4 subnet calculator. Enter CIDR notation to get network address, broadcast, usable hosts, subnet mask, wildcard mask, and binary values instantly.
Free chmod calculator. Toggle read/write/execute checkboxes for owner, group, and public to get the octal permission code and chmod command instantly.
Free visual crontab builder. Select minute, hour, day, month, and weekday from dropdowns to generate a cron expression with human-readable description and next 5 run times.
Free online ULID generator. Create Universally Unique Lexicographically Sortable Identifiers with decoded timestamps. Supports monotonic mode and batch generation up to 100. Fully client-side.
Free online CUID2 generator. Create collision-resistant identifiers with configurable length (2-32). Batch generate up to 100 IDs with collision probability estimates. 100% client-side.
Free online Nanoid generator with custom alphabet, configurable length (1-64), and batch generation up to 100 IDs. See collision probability and total combinations. 100% client-side.
Free online JSON to TOML converter with bidirectional support. Convert JSON to TOML and TOML back to JSON. Pretty-print output. No upload — runs in your browser.
Free online JSON to XML converter with bidirectional support. Convert JSON to XML and XML back to JSON. Configurable root element and pretty-print. No upload needed.
Free online YAML to TOML converter with bidirectional support. Convert YAML to TOML and TOML back to YAML. Adjustable indentation. No upload — everything runs in your browser.
Free numeronym generator and decoder. Convert words like internationalization to i18n and decode common numeronyms like k8s, a11y, and l10n instantly.
Free online leetspeak converter. Transform text into leet (1337) speak at four intensity levels — basic, moderate, advanced, and ultimate with random variation.
Free Morse code converter. Translate text to Morse code and back, plus play the Morse code as audio beeps at adjustable speeds from 5 to 25 WPM.
Free phone number parser. Enter any phone number to detect country, type (mobile/landline/toll-free), extract the national number, and format to E.164 standard.
Convert docker run commands to docker-compose.yml instantly. Parses ports, volumes, env vars, restart policy, network, memory limits, and more — no server uploads.
Generate and verify HMAC signatures using SHA-1, SHA-256, SHA-384, or SHA-512. Output in hex or base64. Verify authenticity of signed messages. All local, no server uploads.
Generate pure CSS background patterns — stripes, dots, grids, checkerboards, and more. Copy-ready CSS code, no images required.
Convert code snippets into beautiful shareable images. Choose themes, fonts, and backgrounds. Perfect for social media and documentation.
Generate random safe network ports for development. Avoids well-known ports (0-1023) and common registered ports. Copy-ready for configs.
Decode Microsoft Outlook SafeLink URLs to reveal the original destination. Paste any safelinks.protection.outlook.com URL to decode it.
Press any key to see its JavaScript keyboard event properties: key, code, keyCode, which, charCode. Essential for web developers.
Compare JavaScript code snippet performance side-by-side. Run benchmarks with configurable iterations and see ops/sec. Free browser-based tool.
Free online REST API tester. Send GET, POST, PUT, DELETE requests with custom headers and body. View formatted responses instantly in your browser.
Free online GraphQL playground. Write and test GraphQL queries with schema introspection, variables, and formatted responses. Runs in your browser.
Free online WebSocket tester. Connect to WebSocket endpoints, send and receive messages, and monitor connection events. Runs in your browser.
Free online API response formatter. Beautify and format JSON, XML, and HTML API responses with syntax highlighting. Copy formatted output instantly.
Free online cURL to code converter. Paste any cURL command and get equivalent code in JavaScript, Python, Go, PHP, and more. Instant conversion.
Free online JWT decoder. Decode JWT tokens, view header and payload, check expiration, and verify signatures. Supports all JWT algorithms.
Free online OAuth 2.0 flow visualizer. Understand authorization code, implicit, client credentials, and PKCE flows with interactive diagrams.
Free online API mock generator. Generate realistic mock API responses from JSON Schema or sample data. Perfect for frontend development and testing.
Free online SQL formatter. Beautify SQL queries with dialect-specific options for MySQL, PostgreSQL, SQLite, and MSSQL. Copy formatted SQL instantly.
Free online SQL to ORM converter. Convert SQL CREATE TABLE statements to Prisma, TypeORM, and Sequelize model definitions instantly.
Free online ERD generator. Create entity relationship diagrams from SQL statements or JSON schema. Visualize database structure instantly in your browser.
Free online SQL query plan analyzer. Paste EXPLAIN output to visualize and analyze query execution plans. Identify bottlenecks and optimize queries.
Free online database migration generator. Generate migration scripts from schema diffs. Compare two SQL schemas and get ALTER TABLE statements.
Free online CSV to SQL converter. Convert CSV data to INSERT statements with automatic type inference. Supports MySQL, PostgreSQL, and SQLite.
Free online SQL regex tester. Test REGEXP patterns across MySQL, PostgreSQL, SQLite, and MSSQL dialects. See matches and differences instantly.
Free online Docker Compose builder. Visually create docker-compose.yml files with service templates for popular stacks. Copy valid YAML instantly.
Free online Kubernetes YAML generator. Generate Deployment, Service, Ingress, and ConfigMap manifests with a visual builder. Copy valid K8s YAML.
Free online GitHub Actions workflow generator. Create CI/CD pipeline YAML for testing, building, and deploying. Templates for popular stacks.
Free online Terraform snippet generator. Generate HCL code for AWS, Azure, and GCP resources. Copy-ready Terraform configurations.
Free online Nginx config generator. Generate nginx.conf for reverse proxy, SSL, caching, load balancing, and security headers. Copy valid config.
Free online cron expression builder. Visually create cron schedules with human-readable descriptions and next-run previews. Supports 5 and 6 field formats.
Free online .env file generator. Generate environment variable files with common templates for Node.js, Python, Docker, and cloud platforms.
Free online Markdown to HTML converter with syntax highlighting, table of contents, and custom themes. Copy or download the HTML output.
Free online Markdown linter. Check your Markdown for style issues, formatting errors, and best practices. Get instant feedback and fixes.
Free online Markdown to slides converter. Create presentation slides from Markdown with themes, transitions, and speaker notes.
Free online README generator. Create professional README.md files for your projects with badges, installation, usage, and contributing sections.
Free online changelog generator. Create professional CHANGELOG.md files following Keep a Changelog format. Copy-ready documentation.
Free online regex visualizer. Create visual diagrams and flowcharts of regular expression patterns. Understand complex regex at a glance.
Free online regex to code converter. Convert regular expressions to JavaScript, Python, Go, Rust, Java, and C# code with proper escaping.
Free interactive regex cheat sheet. Quick reference for regular expression syntax with live examples. Covers character classes, quantifiers, and more.
Free online regex explainer. Understand regular expression patterns with plain English explanations. Break down complex regex step by step.
Free online regex batch tester. Test regular expressions against multiple strings simultaneously. See matches, groups, and highlights.
Free online regex to English converter. Convert regular expression patterns to human-readable descriptions. Perfect for documentation.
Free online string to regex generator. Generate regular expression patterns from example strings. Detect common patterns automatically.
Free online batch file renamer. Rename multiple files at once with sequential numbers, date stamps, or find and replace. Preview new names and download as ZIP. 100% client-side.
Free online data converter hub supporting JSON, YAML, TOML, XML, CSV, and INI. Bidirectional conversion with format auto-detection, swap, and syntax validation.
Free visual regex builder. Compose regular expressions from categorized tokens, test live with highlighting, and get plain-English explanations.