48 Free, No-Ads Developer Tools
Free online developer tools to format, generate, convert, validate, and debug. No sign-up, no server calls, no tracking.
Barcode Generator
Generate Code 128, EAN-13, UPC-A, and more barcodes online. Customize bar width, height, and font. Download as SVG or PNG.
Base64 Encoder/Decoder
Free Base64 encoder and decoder for text, files, and images. Convert images to data URIs. Preview decoded images. All client-side.
Case Converter
Convert text between camelCase, snake_case, kebab-case, PascalCase, Title Case, SCREAMING_SNAKE_CASE, and more. All variants at once.
Copy Paste Characters
Click to copy special characters, symbols, arrows, math operators, Greek letters, and currency signs. Plain Unicode, works everywhere.
Area Chart Race
Animated stacked area chart showing composition changes over time. Stacked and percentage modes. CSV data, fullscreen presentation.
Bar Chart Race
Create animated bar chart race visualizations from CSV data. Watch categories compete and reorder over time. Fullscreen presentation mode.
Bubble Chart Race
Animated bubble chart where circle sizes represent values. Watch bubbles grow and shrink over time. CSV data, fullscreen mode.
Line Chart Race
Animated line chart that draws progressively over time. Also known as horserace or bump chart. CSV data, fullscreen presentation mode.
Color Converter
Convert between HEX, RGB, HSL, and OKLCH. WCAG contrast checker, complementary palette generator, and CSS-ready copy.
Image Converter
Convert images between PNG, JPEG, WebP, and more. Batch processing with quality and resize controls. All client-side, no upload.
CORS Tester
Check CORS headers and security headers for any URL. See Access-Control headers, X-Frame-Options, HSTS, CSP, and more.
CSS Cover Art Generator
Generate abstract, geometric CSS-only cover art. 8 pattern styles, customizable colors and complexity. Export as HTML/CSS or PNG.
Crontab Generator
Build and parse cron expressions visually. Human-readable description and next 5 scheduled runs. Copy for crontab, CI/CD, or schedulers.
CSV Editor
Visual spreadsheet editor for CSV files. Sort, filter, search & replace, add/remove rows and columns. Export as CSV or TSV.
Text Diff
Compare two texts side-by-side or inline with character-level diff highlighting. Additions, deletions, and changes shown in real time.
DNS Lookup
Look up A, AAAA, MX, NS, TXT, CNAME, and SOA records for any domain. Results grouped by record type with one-click copy.
Encrypt / Decrypt
Encrypt and decrypt text with a passphrase using AES-256-GCM. Client-side authenticated encryption — nothing is sent to a server.
Favicon Generator
Generate favicons in all standard sizes from a single image. Get HTML link tags and web manifest JSON. All client-side.
Hash Generator
Generate MD5, SHA-1, SHA-256, SHA-384, and SHA-512 hashes for text and files. Verify integrity with hash comparison. All client-side.
HTML ↔ Markdown
Convert between HTML and Markdown instantly. Configurable heading style, list markers, and link format. Copy or download the result.
HTTP Status Codes
Complete HTTP status code reference. Search by code or name, click to copy. Grouped by category with plain-English descriptions.
Image to Base64
Convert images to Base64 data URIs, HTML img tags, and CSS background-image properties. Reverse mode included. All client-side.
JSON ↔ YAML Converter
Convert between JSON and YAML instantly. Live bidirectional editing with syntax highlighting, validation, and copy support.
JSON Formatter & Validator
Free JSON formatter, validator, and beautifier. Pretty-print with syntax highlighting, minify, validate with error details, and tree view.
JWT Decoder
Free online JWT decoder. Decode JWT tokens into header, payload, and signature with expiration status. All client-side.
Loopkit
Schema-driven SVG animation engine. Under 5KB, zero dependencies. Works with React, SSR, and vanilla JS. Also on npm.
Markdown Repository
Query .md and .mdx files by frontmatter with a Firestore-style API. Works with Next.js App Router and server components.
Markdown to DOCX
Convert Markdown to Word documents (.docx). Custom fonts, colors, and layout. Opens in Word, Pages, Google Docs, and LibreOffice.
Markdown to PDF
Convert Markdown to beautifully formatted PDF. Custom fonts, colors, page size, margins, and line height. All in your browser.
Markdown Preview
Live Markdown editor with GitHub Flavored Markdown support. Synchronized scrolling, syntax highlighting, and HTML export.
Mesh Gradient Generator
Create beautiful mesh gradients with custom colors and positions. Export as CSS background-image or PNG at custom resolution.
OG Tag Validator
Validate Open Graph and Twitter Card meta tags. Preview how links appear on Facebook, LinkedIn, and Twitter/X. Check missing tags.
Password Generator
Generate strong passwords with customizable length, character sets, and strength meter. Uses Web Crypto API for true randomness.
Image Placeholder Generator
Generate placeholder images with custom size, colors, and text. Download as PNG or SVG, or copy the data URI. No external service.
QR Code Generator
Generate QR codes for URLs, WiFi, vCards, phone, email, and SMS. Custom colors and error correction. Download as SVG or PNG.
Aspect Ratio Calculator
Calculate aspect ratios, resize dimensions proportionally, and visualize common ratios like 16:9 and 4:3. Instant copy.
Regex Tester
Test regular expressions with live highlighting, capture groups, pattern explanation, and quick-reference. Export in JS, Python, or Go.
Robots.txt Validator
Validate robots.txt syntax and test URL paths against crawl rules. Check which pages are allowed or blocked for any user-agent.
Sitemap Validator
Validate XML sitemaps for correct structure, URLs, dates, and priorities. Find errors and warnings instantly. Supports urlset and sitemapindex.
Slug Generator
Generate clean, URL-safe slugs from any text. Customize separators, transliterate accents, set max length. Live preview.
SSL Certificate Checker
Check SSL/TLS certificate details for any domain. Expiry dates, issuer, Subject Alternative Names, protocol, and cipher suite.
SVG Optimizer
Optimize and minify SVG files in your browser. Remove metadata, collapse whitespace, shorten colors, and see size savings instantly.
Text to Gradient
Generate unique mesh gradients from any text. Same input always produces the same gradient. Export as CSS or PNG.
Unix Timestamp Converter
Convert between Unix timestamps and human-readable dates. Auto-detects seconds vs milliseconds. Timezone support.
User Agent Parser
Parse any user agent string into browser, OS, engine, and device details. Auto-detects your current browser on load.
UUID Generator
Generate UUID v1, v4, and v7 online. Bulk generation up to 1,000 UUIDs. Toggle uppercase, hyphens. Export as TXT or CSV.
Word & Character Counter
Count words, characters, sentences, and paragraphs. Estimate reading and speaking time. Live updates as you type.
YAML Validator
Validate YAML syntax with inline errors and line numbers. Tree view, auto-format, and common template samples for Kubernetes, Docker, and GitHub Actions.
Built & Maintained by Varstatt
Varstatt is a one-person product studio run by Jurij Tokarski, product engineer since 2011. These tools are free and open — no signup, no catch.