UtilityKit
500+ fast, free tools. Most run in your browser only; Image & PDF tools upload files to the backend when you run them.
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Free Developer Tools — 138 Online Utilities
138 tools · Online Utilities for Developers
A complete developer toolbox in your browser: format and validate JSON/YAML/XML, debug regex, decode JWTs, generate hashes and UUIDs, encode/decode base64 and URLs, lint code, and more. Most tools run entirely client-side so secrets and tokens never leave your machine.
JSON, YAML, XML · 14
🔧JSON FormatterFormat, validate and minify JSON🔧JSON Escape / UnescapeEscape plain text for JSON or decode escaped text🔧JSON Path FinderQuery JSON values using JSONPath-style paths🔧XML Sitemap GeneratorGenerate XML sitemap files from URL lists with optional metadata defaults.🔧JSON to TypeScriptGenerate TypeScript types and interfaces from JSON samples.🔧JSON to Zod SchemaGenerate Zod schema code from JSON input data.🔧JSON to Go StructConvert JSON into Go struct definitions with json tags.🔧JSON to Rust StructGenerate Rust structs from JSON with serde rename hints.🔧Schema JSON-LD GeneratorGenerate JSON-LD for common schema types using guided forms.🔧Package JSON Scaffold GeneratorGenerate package.json scaffolds from project metadata and script presets.🔧JSON to CSharp ClassConvert JSON payload samples into C# class models with inferred nested types.🔧XML Sitemap ValidatorParse pasted sitemap XML for structural issues.✅JSON Schema ValidatorValidate JSON data against a JSON Schema (Draft-07, Draft-2019-09, Draft-2020…🔧JSON Schema Generator from SampleAutomatically infer a JSON Schema from a sample JSON document to bootstrap sc…
Encoding & Decoding · 5
🔧Base64Encode and decode Base64 strings🔧JWT DecoderDecode and inspect JWT tokens🔧URL EncoderEncode and decode URLs🔧HTML Entities Encoder DecoderEncode and decode HTML entities in named/basic and numeric modes.🔧JavaScript String EscapeEncode and decode JavaScript escape sequences for safe string handling.
Hashing & Crypto · 9
🔧Hash GeneratorGenerate SHA-256, SHA-1, MD5 hashes🔧Paste and ShareShare text with a short link, expiry, optional max opens, password, and QR code🔧Box Shadow GeneratorTune blur, spread, offsets, color, and inset shadows with an instant CSS prev…🔧Text Shadow GeneratorStack up to three readable text shadows and export CSS for headings and hero …🔧AES Text EncryptorPBKDF2-hardened AES-GCM encrypt and decrypt.🔧RSA Key GeneratorIssue RSA-OAEP 2048 PEM pairs via Web Crypto.🔐bcrypt Generator & VerifierHash passwords with bcrypt (cost 8–14) and verify hashes in-browser.🔏PGP Encrypt / DecryptEncrypt, decrypt, generate PGP key pairs, and sign/verify messages in-browser…🔧File Hash Multi (MD5, SHA-1, SHA-256, SHA-512)Compute MD5, SHA-1, SHA-256, and SHA-512 of any file in your browser
Regex & Pattern · 4
🔧Regex TesterTest regular expressions with live matches🔧Cron Expression GeneratorBuild 5-field cron expressions quickly🕐Cron Expression DescriberTranslate a cron expression into plain English and preview the next scheduled…🔎Regex Generator from SamplesGenerate a regular expression from positive and negative example strings — ru…
Network, DNS & HTTP · 21
🔧JavaScript MinifierMinify JavaScript by removing comments, trimming whitespace, and outputting c…🔧JavaScript BeautifierBeautify JavaScript snippets with indentation and spacing normalization.🔧HTTP Status LookupSearch HTTP status codes and names with class-based filters and notes.🔧Htaccess Snippet GeneratorGenerate common Apache .htaccess snippet blocks and merge selections.🔧Nginx Snippet GeneratorGenerate and merge common Nginx config snippets for deployment baselines.🔧DNS Lookup ToolQuery public DNS records with SSRF-safe hostname validation🔧HTTP Headers CheckerInspect response status and headers from public HTTPS origins🔧SSL Certificate CheckerPeek TLS certificate metadata with SSRF-safe hostname rules🔧Clip Path GeneratorExplore polygon, circle, ellipse, and inset clip-path presets with live previ…🔧Subnet CalculatorIPv4 network broadcast host ranges from CIDR.🔧IPv4 to IPv6 ConverterMapped IPv6 textual forms such as ::ffff dotted quartet.🌐WHOIS Domain LookupLook up WHOIS registration data for any domain — registrar, creation date, ex…📍IP Geolocation LookupLook up the geolocation of any IPv4 or IPv6 address — country, region, city, …🌍DNS Propagation CheckerCheck DNS propagation across multiple global nameservers to see how widely a …🔄Reverse DNS LookupPerform a reverse DNS lookup (PTR record query) to find the hostname associat…📡Online Ping TestMeasure the response time (latency) of any IP address or hostname from our se…⚡JavaScript Online RunnerRun JavaScript in a sandboxed iframe — instant execution with console output …🔷TypeScript PlaygroundTranspile TypeScript to JavaScript in your browser with configurable target a…📡HTTP Request BuilderSend HTTP requests from your browser via a server-side proxy — set method, he…🔐DNSSEC CheckerLook up DS, DNSKEY, and RRSIG records for a domain to confirm DNSSEC is enabl…🔌Open Port CheckerRun a single TCP connect-test from our backend to confirm whether one port on…
Code & Markup · 17
🔧CSS MinifierMinify CSS by removing comments and whitespace🔧HTML FormatterBeautify and indent raw HTML code🔧HTML MinifierMinify HTML by removing comments and unnecessary whitespace while preserving …🔧CSS BeautifierBeautify CSS with clean indentation and optional comment preservation.🔧SemVer Tester DiffValidate and compare semantic versions, including bump classification.🔧CSS Gradient GeneratorCreate linear or radial gradients with stops, angles, and copy-ready backgrou…🔧CSS Triangle GeneratorCreate directional CSS triangles using the transparent border technique with …🔧CSS Spinner GeneratorBrowse spinner presets, tweak size speed and color, and copy animation-ready …🔧CSS Button GeneratorStyle padding, radius, colors, borders, and optional hover darken with instan…🔧CSS Grid PlaygroundPrototype grid templates, gaps, and alignment with a responsive preview and C…🔧CSS Keyframes GeneratorCompose starter animations with timing controls and copy @keyframes blocks.🔧CSS Transform PlaygroundCombine translate, rotate, scale, and skew with live matrix feedback and CSS …🔧CSS Filter PlaygroundStack blur, color, and tonal CSS filters with sliders and copy-ready filter d…📐CSS Unit ConverterConvert between CSS units — px, em, rem, vh, vw, pt, pc, cm, mm, in — with co…⚖️CSS Specificity CalculatorCalculate and compare the specificity score of any CSS selector to understand…📦CSS Box Model VisualizerVisualize the CSS box model interactively — adjust margin, border, padding, a…🦆SQL Online RunnerQuery CSV and JSON files with SQL in your browser — powered by DuckDB-WASM.
IDs, UUIDs & Tokens · 3
More tools · 65
🔧Color ConverterConvert between HEX, RGB, HSL🔧Unix Time ConverterConvert Unix timestamps to readable date and back🔧cURL to FetchConvert common cURL commands to fetch()🔧Meta Tag GeneratorGenerate essential HTML head tags for SEO and metadata in one place.🔧Robots.txt GeneratorGenerate a valid robots.txt with user-agent, allow/disallow, sitemap, and hos…🔧Glob TesterTest glob patterns against newline file/path candidates.🔧MIME Type LookupFind MIME types from extensions and reverse-map MIME to extensions.🔧User Agent ParserParse user-agent strings into browser, engine, OS, and device details.🔧URL ParserParse URLs into protocol, host, path, query parameters, and hash parts.🔧Data URL BuilderBuild and decode data URLs with MIME, charset, and Base64 options.🔧OG Tag GeneratorGenerate Open Graph meta tags with preview-friendly fields and copy-ready out…🔧Twitter Card GeneratorGenerate Twitter/X card tags and preview social metadata quickly.🔧Canonical Tag GeneratorNormalize URLs and generate canonical link tags for SEO-safe page metadata.🔧Gitignore GeneratorGenerate merged and deduplicated .gitignore output from stack presets.🔧Editorconfig GeneratorGenerate .editorconfig with global defaults and per-extension overrides.🔧License GeneratorGenerate common OSS license templates with year and copyright holder.🔧README GeneratorGenerate markdown README scaffolds from core project fields.🔧Dockerfile GeneratorGenerate Dockerfile templates for Node, Python, and static Nginx apps.🔧GitHub Actions Workflow GeneratorGenerate starter CI/deploy workflow YAML for common project types.🔧RSS Atom GeneratorGenerate RSS 2.0 and Atom XML feeds from metadata and entry rows.🔧Border Radius GeneratorShape corners with unified or per-corner sliders and export shorthand border-…🔧Glassmorphism GeneratorTune blur, saturation, translucency, and borders for frosted glass panels.🔧Neumorphism GeneratorCraft soft extruded or inset soft UI shadows tuned for light and dark surfaces.🔧Flexbox PlaygroundTune flex-direction, alignment, gap, and item counts while copying container …🔧Aspect Ratio HelperConvert width and height pairs into modern aspect-ratio CSS plus legacy paddi…🔧Container Query HelperAuthor @container boilerplate with names and breakpoints for component-driven…🔧Scrollbar StylerTint scrollbar thumbs and tracks for WebKit and Firefox using copy-ready pseu…🔧SERP Preview ToolDesktop and mobile style snippets with soft character guides.🔧Hreflang Tag GeneratorBuild alternate link rows for multilingual SEO.🔧Keyword Density CheckerToken frequencies with optional stopword trimming.🔧Password Strength CheckerHeuristic scoring without uploading secrets.🔧Email Header AnalyzerSummarize Received chains and auth hints from pasted headers.🔑Nano ID GeneratorGenerate secure, URL-friendly unique string IDs with customizable alphabet an…🆔CUID GeneratorGenerate Collision-Resistant Unique Identifiers (CUIDs) — sequential, client-…❄️Snowflake ID GeneratorGenerate Twitter-style Snowflake IDs — 64-bit time-ordered unique integers us…🍃MongoDB ObjectId GeneratorGenerate MongoDB-compatible ObjectIds and decode existing ones to extract the…🔏SSH Public Key FingerprintCalculate the MD5 and SHA-256 fingerprints of an SSH public key to verify ide…🔐htpasswd GeneratorGenerate bcrypt, MD5-APR, or SHA1 htpasswd entries for HTTP Basic Authenticat…🔒Password Entropy CalculatorCalculate the entropy of any password in bits and estimate the brute-force ti…♿WCAG Contrast CheckerCheck foreground and background color contrast ratios against WCAG 2.1 AA and…👁Color Blindness SimulatorSimulate how colors or images appear to people with various types of color bl…🌊Tailwind Class to CSS ConverterLook up what CSS properties any Tailwind CSS utility class generates, includi…📈Cubic Bezier EditorVisually edit and preview CSS cubic-bezier easing curves with interactive con…🔤Font Pairing PreviewerPreview curated Google Fonts pairings for headings and body text with sample …📱Responsive Breakpoint PreviewerPreview any URL at common responsive breakpoints (mobile, tablet, desktop) si…📧MX Record LookupLook up the Mail Exchange (MX) records for any domain to see which mail serve…🔍Website Status CheckerCheck whether any website or URL is up or down and see its HTTP response code…🤖Robots.txt TesterTest whether a specific URL is allowed or blocked for a given user-agent acco…📜X.509 Certificate InspectorDecode PEM or DER (base64) X.509 certificates to extract subject, issuer, SAN…🧜Mermaid Live EditorWrite Mermaid diagram syntax and see a live SVG preview — flowcharts, sequenc…🕸️Graphviz DOT RendererRender Graphviz DOT language graphs in-browser with WASM — supports dot, neat…🐍Python Online CompilerRun Python 3 code in your browser via Pyodide — no install, no server.📐PlantUML RendererWrite PlantUML diagrams and preview them as SVG — sequence, class, activity, …📸Page Screenshot ServiceCapture full-page or viewport screenshots of any public URL as PNG or JPG usi…🔦Lighthouse Lite AuditRun a Lighthouse-style performance, SEO, accessibility, and best practices au…🔗Broken Link CheckerFind broken and dead links on any webpage. Live status updates and CSV export…🔧Hex & Binary ViewerInspect any file as a hex + ASCII dump in your browser📧SPF Record CheckerLook up and parse a domain's SPF DNS record. Validates mechanisms, counts DNS…🛡️DMARC Record CheckerLook up the DMARC TXT record at _dmarc.<domain>, parse every tag (p, sp, pct,…🔑DKIM Record CheckerFetch a DKIM TXT record at <selector>._domainkey.<domain>, parse the public k…🛠️DMARC Record GeneratorBuild a valid DMARC TXT record with policy, percentage, alignment modes, and …🛠️SPF Record GeneratorCompose an SPF TXT record from email-provider presets, custom includes, and I…🚫RBL Blacklist CheckCheck an IPv4 address against four major DNS-based blocklists in parallel — S…📨SMTP Server TestConnect to any SMTP host on port 25 (or a custom port), capture the banner, s…🌐Subdomain FinderDiscover subdomains for any domain via passive enumeration of Certificate Tra…