Developer & Web Tools
Everyday utilities for developers, designers and site owners. Format, validate and minify JSON, XML, HTML, CSS, JavaScript, SQL and YAML; encode and decode Base64, URLs, entities and hashes; convert between JSON, CSV, XML, YAML and TOML; parse URLs and cron expressions; generate CSS gradients, shadows, grids and meta tags; and check SEO snippets and WCAG accessibility basics. Nothing you paste is executed or uploaded, and every tool explains what it checks so you know where automated results end and manual review begins.
Developer & Web Subcategories
- Format & ValidateFormat, validate, minify and diff JSON, XML, HTML, CSS, JS, SQL and YAML.21 tools
- Encoding & SecurityBase64, URL, hashes, HMAC, bcrypt, AES, UUIDs and JWTs.19 tools
- Data FormatsConvert JSON, CSV, XML, YAML and TOML; generate types and tables.11 tools
- SEOMeta checks, SERP and social previews, robots.txt, sitemaps and schema.10 tools
- CSS & FrontendGradients, shadows, grids, units, colours, SVG and meta tags.17 tools
- URL & HTTPParse URLs, build UTM links, explain cron and calculate subnets.9 tools
- AccessibilityContrast, colour-blindness, headings, links and WCAG checks.12 tools
All 99 Developer & Web Tools
Listed by subcategory, most popular first.
Format & Validate (21)
Format, validate, minify and diff JSON, XML, HTML, CSS, JS, SQL and YAML.
- JSON FormatterPretty-print JSON with clear error locations.Open Tool
- JSON ValidatorCheck JSON syntax and find the exact error.Open Tool
- Regex TesterTest JavaScript regular expressions safely.Open Tool
- HTML FormatterBeautify and indent HTML code.Open Tool
- SQL FormatterBeautify SQL with dialect-aware formatting.Open Tool
- XML FormatterPretty-print or minify XML with error locations.Open Tool
- JavaScript FormatterBeautify JavaScript code with clean indentation.Open Tool
- CSS FormatterBeautify and indent CSS stylesheets.Open Tool
- JSON MinifierRemove whitespace from JSON to shrink it.Open Tool
- JavaScript MinifierMinify JavaScript and see the size saved.Open Tool
- CSS MinifierCompress CSS by removing comments and whitespace.Open Tool
- HTML MinifierRemove comments and extra whitespace from HTML.Open Tool
- JSON Tree ViewerExplore JSON as an expandable, keyboard-friendly tree.Open Tool
- JSON DiffCompare two JSON documents and list every change.Open Tool
- XML ValidatorCheck XML is well-formed and find the error.Open Tool
- YAML FormatterValidate YAML and re-indent it cleanly.Open Tool
- SQL MinifierStrip comments and extra whitespace from SQL.Open Tool
- XML MinifierStrip whitespace and comments from XML.Open Tool
- JSON Schema ValidatorValidate JSON against a JSON Schema.Open Tool
- JSONPath TesterRun JSONPath queries against your JSON.Open Tool
- XPath TesterEvaluate XPath expressions against XML.Open Tool
Encoding & Security (19)
Base64, URL, hashes, HMAC, bcrypt, AES, UUIDs and JWTs.
- Base64 EncoderEncode text or any file to Base64.Open Tool
- Base64 DecoderDecode Base64 to text or a downloadable file.Open Tool
- URL EncoderPercent-encode text or a full URL safely.Open Tool
- URL DecoderDecode %XX text and break a URL into parts.Open Tool
- JWT DecoderDecode a JWT header and payload (no verification).Open Tool
- UUID GeneratorGenerate v4 and v7 UUIDs, and check a UUID.Open Tool
- Hash GeneratorMD5, SHA-1, SHA-256, SHA-384 and SHA-512 hashes.Open Tool
- HTML Entity EncoderConvert text to HTML entities.Open Tool
- HTML Entity DecoderConvert HTML entities back to text.Open Tool
- Bcrypt GeneratorCreate and verify bcrypt password hashes.Open Tool
- HMAC GeneratorHMAC-SHA256, SHA-384 and SHA-512 signatures.Open Tool
- AES Encrypt/DecryptEncrypt text with a passphrase (AES-256-GCM).Open Tool
- String EscaperEscape text for JSON, JS, HTML, CSV and SQL.Open Tool
- Unicode EscapeConvert text to and from \uXXXX and &#x; escapes.Open Tool
- Hex Encoder/DecoderConvert text to hexadecimal bytes and back.Open Tool
- Base32 Encoder/DecoderEncode and decode RFC 4648 Base32.Open Tool
- Punycode ConverterConvert international domain names to xn-- form.Open Tool
- ULID / NanoID GeneratorGenerate sortable ULIDs or compact NanoIDs.Open Tool
- JWT GeneratorCreate HS256 test tokens for development.Open Tool
Data Formats (11)
Convert JSON, CSV, XML, YAML and TOML; generate types and tables.
- JSON to CSVConvert JSON arrays and objects to CSV.Open Tool
- CSV to JSONConvert CSV rows to a JSON array of objects.Open Tool
- XML to JSONConvert XML to JSON with attribute options.Open Tool
- JSON to XMLConvert JSON to XML with a custom root element.Open Tool
- YAML to JSONConvert YAML to JSON with clear error reporting.Open Tool
- JSON to YAMLConvert JSON to clean, readable YAML.Open Tool
- Markdown TableBuild Markdown tables in an editable grid.Open Tool
- JSON to TypeScriptGenerate TypeScript interfaces from sample JSON.Open Tool
- HTML to JSXConvert HTML snippets into React JSX.Open Tool
- Mock JSON DataGenerate clearly fictional sample JSON records.Open Tool
- TOML to JSONConvert TOML configuration files to JSON.Open Tool
SEO (10)
Meta checks, SERP and social previews, robots.txt, sitemaps and schema.
- Keyword Density CheckerKeyword density and top phrases.Open Tool
- SERP Snippet PreviewPreview a Google result snippet.Open Tool
- Meta Title CheckerCheck title tag length and pixel width.Open Tool
- Meta Description CheckerCheck description length and preview it.Open Tool
- Robots.txt GeneratorBuild a valid robots.txt file.Open Tool
- Sitemap XML GeneratorCreate a sitemap.xml from a URL list.Open Tool
- Open Graph PreviewPreview link cards and og: meta tags.Open Tool
- URL Slug GeneratorMake clean SEO-friendly URL slugs.Open Tool
- JSON-LD Schema GeneratorBuild Organization, Article, FAQ and breadcrumb schema.Open Tool
- Hreflang GeneratorCreate hreflang tags for language and region versions.Open Tool
CSS & Frontend (17)
Gradients, shadows, grids, units, colours, SVG and meta tags.
- Color Code ConverterConvert HEX, RGB, HSL, HWB and CMYK colour codes.Open Tool
- CSS Gradient GeneratorDesign linear, radial and conic CSS gradients.Open Tool
- Meta Tag GeneratorGenerate title, description, Open Graph and Twitter tags.Open Tool
- Box Shadow GeneratorLayer up to three box shadows with a live preview.Open Tool
- Border Radius GeneratorShape corners with individual and elliptical radii.Open Tool
- Flexbox PlaygroundTry flexbox container and item settings live.Open Tool
- CSS Grid GeneratorBuild grid templates and named areas with CSS.Open Tool
- CSS Unit ConverterConvert px, rem, em, pt, vw and vh with your base size.Open Tool
- SVG OptimizerMinify and clean SVG markup with SVGO.Open Tool
- CSS Spinner GeneratorCreate CSS spinners that respect reduced motion.Open Tool
- HTML Table GeneratorBuild accessible HTML tables with caption and scope.Open Tool
- Cubic Bezier EditorEdit CSS easing curves with a draggable graph.Open Tool
- Clip-Path GeneratorCreate polygon, circle, ellipse and inset clip paths.Open Tool
- Fluid Type CalculatorGenerate CSS clamp() values for fluid font sizes.Open Tool
- SVG to Data URIEncode SVG as a compact data URI for CSS.Open Tool
- Specificity CalculatorCalculate and compare CSS selector specificity.Open Tool
- .gitignore GeneratorBuild a .gitignore file from bundled templates.Open Tool
URL & HTTP (9)
Parse URLs, build UTM links, explain cron and calculate subnets.
- URL ParserSplit a URL into parts and edit its query parameters.Open Tool
- UTM Link BuilderBuild campaign URLs with UTM parameters.Open Tool
- Subnet CalculatorIPv4 CIDR calculator: network, broadcast, host range.Open Tool
- HTTP Status CodesSearch HTTP status codes, meanings and common causes.Open Tool
- Cron ExplainerExplain cron schedules in plain English with next runs.Open Tool
- User Agent ParserParse a user-agent string into browser, OS and device.Open Tool
- Chmod CalculatorConvert Unix permissions between numeric and symbolic.Open Tool
- .htaccess RedirectsGenerate Apache 301/302 redirect rules from URL lists.Open Tool
- MIME Type LookupFind MIME types by extension and extensions by type.Open Tool
Accessibility (12)
Contrast, colour-blindness, headings, links and WCAG checks.
- WCAG Contrast CheckerCheck text and UI colour contrast against WCAG 2.2.Open Tool
- Contrast Ratio CalculatorContrast maths for any CSS colour, with transparency.Open Tool
- Color Blindness SimulatorPreview images and colours as colour-blind users may see.Open Tool
- Accessible Palette GeneratorTints, shades and colour harmonies with contrast info.Open Tool
- HTML Accessibility CheckerRule-based HTML accessibility scan with WCAG 2.2 references.Open Tool
- Heading Structure CheckerOutline headings and landmarks; flag skipped levels.Open Tool
- Alt Text ChecklistDecide what alt text an image needs and lint your own.Open Tool
- Keyboard Accessibility ChecklistInteractive keyboard test checklist with WCAG 2.2 criteria.Open Tool
- Link Text CheckerFind vague, empty or confusing link text.Open Tool
- ARIA Attribute ReferenceSearchable WAI-ARIA 1.2 roles, states and properties.Open Tool
- Target Size CheckerCheck control size and spacing against WCAG 2.5.8.Open Tool
- Text Spacing TesterApply WCAG 1.4.12 text spacing to HTML to find clipping.Open Tool
Frequently Asked Questions
How many Developer & Web tools are there?
There are 99 free Developer & Web tools in 7 subcategories: Format & Validate, Encoding & Security, Data Formats, SEO, CSS & Frontend, URL & HTTP, Accessibility.
Which Developer & Web tools are used most?
The most popular are JSON Formatter, JSON Validator, Regex Tester. Tools on this page are listed in order of popularity within each subcategory.
Are my files and text uploaded?
No. Every tool in this category runs in your browser, so your files and text stay on your device.