Published March 27, 2026 · 18 min read
Every minute you spend creating an account is a minute you are not building. The best developer tools get out of your way and let you work. No email verification, no credit card, no onboarding wizard. You open the page, use the tool, and move on.
We curated 50 developer tools that meet three criteria: they are completely free, they require zero signup, and they are genuinely useful in a professional workflow. Every tool on this list is available on spunk.codes or linked to its original source. We organized them into ten categories so you can jump straight to what you need.
Create linear, radial, and conic gradients with a visual editor. Copy the CSS with one click. Supports multi-stop gradients and angle adjustments.
Try It FreeVisual flexbox layout builder. Set direction, wrap, justify, and align properties while watching a live preview update in real time. Exports clean CSS.
Try It FreeDefine rows, columns, gaps, and template areas with drag-and-drop. Generates production-ready CSS Grid code you can paste directly into your stylesheet.
Try It FreeLayer multiple box shadows with controls for offset, blur, spread, and color. Live preview on a sample card element so you see exactly what ships.
Try It FreeBuild keyframe animations visually. Set timing functions, delays, iteration counts, and direction. Outputs the full @keyframes block plus the animation shorthand.
Try It FreePaste raw JSON, get it formatted with syntax highlighting. Catches parse errors instantly and shows the exact line and character where the problem is.
Try It FreeConvert JSON arrays to CSV files in one click. Handles nested objects by flattening keys with dot notation. Download the CSV directly.
Try It FreeUpload a CSV file or paste the content. Outputs a JSON array with proper typing — numbers stay numbers, booleans stay booleans.
Try It FreeConvert YAML configuration files to JSON and back. Preserves comments as a separate field and handles multi-document YAML files.
Try It FreeFormat messy SQL queries into readable, indented code. Supports MySQL, PostgreSQL, SQLite, and SQL Server dialects with proper keyword capitalization.
Try It FreeResize images to exact pixel dimensions or by percentage. Maintains aspect ratio by default. Processes everything in your browser — your images never leave your device.
Try It FreeCompress JPEG, PNG, and WebP images with adjustable quality. Typically achieves 60-80% file size reduction with no visible quality loss.
Try It FreeConvert PNG images to WebP format for faster page loads. WebP files are typically 25-35% smaller than equivalent PNGs at the same visual quality.
Try It FreeEdit SVG files directly in your browser. Modify paths, colors, transforms, and viewBox without opening a desktop application. Export clean, optimized SVG code.
Try It FreeRemove backgrounds from images using client-side AI. Works well on product photos, headshots, and logos. No watermark on the output.
Try It FreeGenerate harmonious color palettes from a base color. Supports complementary, analogous, triadic, and split-complementary schemes with hex, RGB, and HSL output.
Try It FreeConvert between hex, RGB, HSL, HSV, and CMYK color formats instantly. Shows a live preview swatch so you can verify the color visually.
Try It FreeCheck foreground/background color combinations against WCAG 2.1 AA and AAA standards. Shows pass/fail for normal text, large text, and UI components.
Try It FreeUpload an image or enter a color to see how it appears under eight types of color vision deficiency. Essential for accessible design.
Try It FreeMix two or more colors together and see the result. Adjust blend ratios and mixing modes. Useful for creating brand color variations.
Try It FreeEncode text or files to Base64, or decode Base64 strings back to their original form. Handles binary files, images, and UTF-8 text.
Try It FreePercent-encode special characters for URLs, or decode encoded URLs back to readable text. Handles Unicode characters and nested encoding.
Try It FreeCount words, characters, sentences, and paragraphs in any text. Estimates reading time and shows keyword density. Useful for SEO content writing.
Try It FreeGenerate placeholder text in paragraphs, sentences, or words. Supports classic Latin, hipster, and plain English variants for mockups and prototypes.
Try It FreeConvert Markdown documents to clean HTML. Supports GitHub Flavored Markdown including tables, task lists, and fenced code blocks with syntax highlighting.
Try It FreeGenerate Open Graph, Twitter Card, and standard meta tags for any page. Preview how your content will appear when shared on social media platforms.
Try It FreeBuild a valid robots.txt file with allow/disallow rules for specific crawlers. Includes sitemap declaration and crawl-delay settings.
Try It FreeGenerate JSON-LD structured data for articles, products, FAQs, recipes, and local businesses. Outputs valid Schema.org markup ready to paste into your page.
Try It FreeCreate XML sitemaps from a list of URLs. Set priority, change frequency, and last modified dates. Download the file or copy the XML directly.
Try It FreeAnalyze any URL for performance issues. Checks image sizes, render-blocking resources, JavaScript execution time, and provides actionable recommendations.
Try It FreeSend GET, POST, PUT, PATCH, and DELETE requests from your browser. Set custom headers, body content, and authentication. View formatted response with timing data.
Try It FreeView the complete HTTP response headers for any URL. Check security headers, cache settings, content types, and redirect chains.
Try It FreeQuery A, AAAA, CNAME, MX, TXT, NS, and SOA records for any domain. Shows TTL values and record data in a clean, readable format.
Try It FreeLook up domain registration information including registrar, creation date, expiration date, and nameservers. Works for all major TLDs.
Try It FreeDecode JSON Web Tokens to inspect the header, payload, and signature. Checks expiration time and identifies the signing algorithm. Never sends your token to a server.
Try It FreeConvert HTML pages to clean Markdown. Handles tables, images, links, headings, and lists. Useful for migrating content to static site generators.
Try It FreeConvert between Unix timestamps and human-readable dates. Supports seconds and milliseconds. Shows the date in your local timezone and UTC simultaneously.
Try It FreeConvert numbers between binary, octal, decimal, and hexadecimal. Supports custom bases from 2 to 36. Shows step-by-step conversion for learning.
Try It FreeConvert between hundreds of units across length, weight, temperature, volume, speed, and data storage. Includes both metric and imperial systems.
Try It FreeConvert between px, rem, em, vw, vh, and percentages. Set a base font size and see all equivalent values. Essential for responsive design work.
Try It FreeGenerate cryptographically secure passwords with customizable length, character sets, and exclusion rules. Calculates entropy and crack time estimates.
Try It FreeGenerate MD5, SHA-1, SHA-256, and SHA-512 hashes from text or files. All processing runs client-side — your data never leaves the browser.
Try It FreeGenerate v4 UUIDs individually or in bulk. Copy a single UUID or generate thousands at once for database seeding and testing scripts.
Try It FreeCheck the SSL/TLS certificate for any domain. Shows issuer, expiration date, certificate chain, and protocol version. Alerts on expiring or misconfigured certs.
Try It FreeBuild a Content Security Policy header with a visual editor. Set directives for scripts, styles, images, fonts, and frames. Outputs a copy-ready header value.
Try It FreeGenerate QR codes for URLs, text, WiFi credentials, contact cards, and more. Customize colors, size, and error correction level. Download as PNG or SVG.
Try It FreeWrite and test regular expressions with real-time matching, capture group highlighting, and a cheat sheet panel. Supports JavaScript, Python, and Go regex flavors.
Try It FreeBuild cron expressions with a visual interface. See the next 10 run times calculated from your expression so you can verify the schedule before deploying.
Try It FreeCompare two blocks of text side by side. Highlights additions, deletions, and modifications line by line. Useful for comparing config files or code snippets.
Try It FreeGenerate placeholder images with custom dimensions, background colors, and text. Download as PNG or use a direct URL in your HTML for rapid prototyping.
Try It FreeThe average developer creates 100+ online accounts over their career. Each account is a potential data breach waiting to happen. Each signup flow adds friction that interrupts your workflow. The most productive developers choose tools that eliminate this friction entirely.
Every tool on spunk.codes runs directly in your browser. Your data stays on your device. There is no server processing, no account creation, and no usage tracking. You open the page, use the tool, and close the tab. That is how developer tools should work.
While browser-based tools handle most tasks, serious development still benefits from solid hardware. A good mechanical keyboard, an ultrawide monitor, and a reliable laptop dock transform your productivity. Check the latest developer accessories on Amazon to set up your ideal workspace.
If you work with cryptocurrency or Web3 development, a hardware wallet like the Ledger Nano is essential for securing your test funds and production wallets.
No signup. No credit card. No limits. Every tool runs in your browser with zero tracking.
Browse All Tools Go Pro — $9.99/mo