152 live tools
Developer & Webmaster
Formatters, generators, and encoding utilities.
JSON, CSS, cron, JWT, regex, and encoding utilities that run in the browser. Nothing is uploaded. Use these for local debugging, then confirm production output with the toolchain you actually ship.
Developer expansion 4 Dec 2026
-
URL Parser (Protocol/Host/Path/Query Breakdown)
URL Parser (Protocol/Host/Path/Query Breakdown). Browser-side only.
Open tool -
Query String to JSON Converter
Query String to JSON. Browser-side only.
Open tool -
Basic JSON Schema Validator
Basic JSON Schema Validator. Browser-side only.
Open tool -
Structured JSON Diff Viewer
Structured JSON Diff Viewer. Browser-side only.
Open tool -
YAML Linter
YAML Linter. Browser-side only.
Open tool -
TOML to JSON Converter
TOML to JSON. Browser-side only.
Open tool -
INI File to JSON Converter
INI File to JSON. Browser-side only.
Open tool -
CSV to SQL INSERT Generator
CSV to SQL INSERT. Browser-side only.
Open tool -
SQL WHERE Clause Builder
SQL WHERE Clause Builder. Browser-side only.
Open tool -
SQL JOIN Visualizer
SQL JOIN Visualizer. Browser-side only.
Open tool -
Database Connection String Builder
Database Connection String Builder. Browser-side only.
Open tool -
API Key Format Validator (Per Provider Pattern)
API Key Format Validator (Per Provider Pattern). Browser-side only.
Open tool -
Webhook URL Format Validator
Webhook URL Format Validator. Browser-side only.
Open tool -
Mermaid Flowchart Code Generator
Mermaid Flowchart Code. Browser-side only.
Open tool -
PlantUML Snippet Generator
PlantUML Snippet. Browser-side only.
Open tool -
ASCII Table Generator from CSV
ASCII Table Generator from CSV. Browser-side only.
Open tool -
Shell Script Shebang & Permission Generator
Shell Script Shebang & Permission. Browser-side only.
Open tool -
Crontab Syntax Validator
Crontab Syntax Validator. Browser-side only.
Open tool -
IPv6 Address Compressor/Expander
IPv6 Address Compressor/Expander. Browser-side only.
Open tool -
MAC Address Format Validator
MAC Address Format Validator. Browser-side only.
Open tool
Developer expansion 11 Dec 2026
-
VLAN ID Range Calculator
VLAN ID Range. Browser-side only.
Open tool -
DNS TTL Countdown Calculator
DNS TTL Countdown. Browser-side only.
Open tool -
robots.txt Validator
robots.txt Validator. Browser-side only.
Open tool -
HTML/XML Entity Encoder-Decoder
HTML/XML Entity Encoder-Decoder. Browser-side only.
Open tool -
Unicode Code Point Lookup
Unicode Code Point. Browser-side only.
Open tool -
Emoji Shortcode to Unicode Converter
Emoji Shortcode to Unicode. Browser-side only.
Open tool -
Zero-Width Character Detector
Zero-Width Character Detector. Browser-side only.
Open tool -
Homoglyph/Lookalike Character Detector
Homoglyph/Lookalike Character Detector. Browser-side only.
Open tool -
Text Encoding Detector (UTF-8 vs Latin-1)
Text Encoding Detector (UTF-8 vs Latin-1). Browser-side only.
Open tool -
Line Ending (CRLF/LF) Converter
Line Ending (CRLF/LF). Browser-side only.
Open tool -
Tab-to-Space Converter
Tab-to-Space. Browser-side only.
Open tool -
Indentation Width Converter
Indentation Width. Browser-side only.
Open tool -
File Extension to MIME Type Lookup
File Extension to MIME Type. Browser-side only.
Open tool -
MIME Type to File Extension Lookup
MIME Type to File Extension. Browser-side only.
Open tool -
GraphQL Query Cost Estimator
GraphQL Query Cost. Browser-side only.
Open tool
Redirects, TLS PEM, and CSS tokens
-
301 Redirect Map Generator (CSV to Rules)
Turn from,to CSV rows into Apache RewriteRule and nginx return 301 blocks.
Open tool -
.htaccess to Nginx Config Converter
Turn RewriteRule lines into nginx rewrite or return. Ignores RewriteCond.
Open tool -
Nginx to Apache Config Converter
Turn nginx rewrite and return 301/302 lines into RewriteRule.
Open tool -
SSL Certificate Chain Order Checker
Split PEM CERTIFICATE blocks, read CN OIDs, and check leaf-then-issuer order. Does not score expiry dates.
Open tool -
CSR (Certificate Signing Request) Decoder
Read a BEGIN CERTIFICATE REQUEST PEM, show subject CN from OID 2.5.4.3, and byte size. Does not sign or verify.
Open tool -
GPG Key Fingerprint Formatter
Normalize a GPG fingerprint to grouped hex (40 or 64 digits). Does not fetch keys or hash a file.
Open tool -
Data URI Size Calculator
Parse a data: URI, report header, decoded bytes, and encoded length. Not a generic UTF-8 string counter.
Open tool -
CSS Specificity Calculator
Score a selector as (IDs, classes, types) plus the a*100+b*10+c shorthand. Not a full:is()/:where() engine.
Open tool -
ARIA Role Reference Builder
Emit a small HTML example and required notes for a chosen ARIA role. Not a full WCAG audit.
Open tool -
SVG-to-Base64 Converter
Encode SVG markup as a data:image/svg+xml;base64 URI. Does not rasterize PNG and is not a generic Base64 box.
Open tool -
SVG Sprite Sheet Builder
Wrap one or more SVG roots into a hidden <svg> of <symbol> elements. Not PNG and not a Base64 data URI.
Open tool -
CSS Custom Properties Generator
Turn name|value rows into a:root { --token: value } block. Not a minifier and not a specificity score.
Open tool
HTTP limits, encoding, PWA and search tags
-
API Rate Limit Calculator (RPS to Daily Cap)
Convert requests per second into hourly and daily caps, with an optional burst that is not added to the day total.
Open tool -
Pagination Offset/Limit Calculator
Turn page number, page size, and total items into SQL offset, limit, item range, and last page.
Open tool -
Base32 Encoder/Decoder
Encode UTF-8 to RFC 4648 Base32 (A-Z2-7) or decode it back. Not Base64 and not Base58.
Open tool -
Base58 Encoder/Decoder
Encode UTF-8 with the Bitcoin Base58 alphabet (no 0, O, I, l) or decode it back. Not Base32 or Base64.
Open tool -
URL Shortener Slug Generator
Generate random short-link codes of a set length from a URL-safe alphabet. Does not hyphenate a phrase.
Open tool -
PWA Manifest.json Generator
Build a Web App Manifest with name, short_name, start_url, display, theme, and 192/512 icons. Not the tiny favicon snippet.
Open tool -
Service Worker Cache Strategy Snippet Generator
Emit a small fetch handler for cache-first, network-first, or stale-while-revalidate. Not a full Workbox build.
Open tool -
Core Web Vitals Threshold Checker
Band LCP, INP, and CLS against Google good / needs-improvement / poor thresholds. Does not measure a URL.
Open tool -
XML Sitemap Validator
Structural scan for urlset or sitemapindex, xmlns, loc, and lastmod. Not a 50k URL counter (sibling page).
Open tool -
Sitemap URL Count & Size Checker
Count loc tags and UTF-8 bytes of a pasted sitemap against Google 50,000 URL and 50 MB uncompressed caps.
Open tool -
Canonical Tag Generator
Emit a single rel=canonical link tag from an absolute http(s) URL, with optional trailing-slash strip.
Open tool -
Hreflang Tag Generator
Build rel=alternate hreflang tags from language-region codes and URLs, plus optional x-default.
Open tool -
JSON-LD Article Schema Generator
Build schema.org Article JSON-LD from headline, author, datePublished, and URL. Not Product or FAQPage.
Open tool -
JSON-LD Product Schema Generator
Build schema.org Product JSON-LD with Offer price, currency, and availability. Not Article or FAQPage.
Open tool -
FAQ Schema Markup Generator
Turn question|answer rows into schema.org FAQPage JSON-LD. Not Article or Product schema.
Open tool -
Twitter Card Markup Validator
Scan pasted HTML for twitter:card, title, description, and image. Does).
Open tool -
SERP Title & Meta Description Length Checker
Score a Google-style title (50-60) and meta (150-160) together.
Open tool
Config, containers and package files
-
.env File Parser & Validator
Parse KEY=VALUE lines, count keys, flag duplicates, empty values, and lines that are not valid env assignments.
Open tool -
Dockerfile Linter & Formatter
Trim Dockerfile lines, require FROM, flag latest tags, missing USER, and ADD when COPY would do.
Open tool -
docker-compose YAML Validator
Text scan for services: plus image: or build:. Not a YAML parser and not the OpenAPI scanner.
Open tool -
Kubernetes Resource Request/Limit Calculator
CPU millicores and memory Mi requests vs limits, times replica count, with a limit-below-request flag.
Open tool -
.gitignore Generator
Concatenate Node, Python, macOS, and Windows ignore templates from checkboxes. Not a git command cheatsheet.
Open tool -
EditorConfig Generator
Emit a root EditorConfig from indent style, size, charset, and newline. Not ESLint and not Prettier.
Open tool -
ESLint Config Generator
JSON snippet with env, eslint:recommended, and optional no-console. Not Prettier and not a full flat config runner.
Open tool -
Prettier Config Generator
Prettier.prettierrc JSON from printWidth, tabWidth, singleQuote, semi, and trailingComma.
Open tool -
Tailwind Color Palette Config Generator
Mix a hex toward white and black into a 50-950 Tailwind color object for theme.extend.colors.
Open tool -
Webpack Config Snippet Generator
CommonJS webpack.config.js snippet from entry, output filename, and mode. Not a Vite config.
Open tool -
Vite Config Snippet Generator
ESM vite.config.js with defineConfig and optional React or Vue plugin import. Not Webpack.
Open tool -
npm Scripts Cheat Sheet Builder
package.json scripts block for dev, build, test, and lint from a bundler pick. Not a full package.json.
Open tool -
Node.js Engines Field Compatibility Checker
Compare a current Node major to engines.node like >=18 <23. Not a full SemVer range matcher.
Open tool -
Python requirements.txt Formatter
Sort requirement lines, drop blanks and comments, flag packages without == pins.
Open tool -
pip Freeze Diff Tool
Diff two pip freeze dumps: added, removed, and version changes. Not a requirements sorter.
Open tool -
Composer (PHP) Command Cheat Sheet
Print Composer commands for require, update, dump-autoload, or create-project. Not npm scripts.
Open tool -
Cargo (Rust) Command Cheat Sheet
Print cargo new, build, test, or clippy commands. Not Composer and not npm.
Open tool -
Go Module Version Parser
Parse module path, go version, and require lines from a pasted go.mod. Not cargo or npm.
Open tool -
Regex-to-English Explainer
Walk a regex and emit English for tokens, classes, and quantifiers. Does not run matches like the Regex Tester.
Open tool -
Cron Expression to Plain-English Explainer
Explain a pasted 5 or 6 field cron (lists, ranges, steps). Does not build cron or list next run times.
Open tool
API specs and collections
-
GraphQL Schema Formatter
Pretty-print a pasted GraphQL schema with brace indent and count type/interface/enum/input units.
Open tool -
OpenAPI Swagger YAML Validator
JSON.parse OpenAPI if possible; else scan text for openapi:/swagger: and paths:. Issue list, not a YAML parser.
Open tool -
Postman Collection to Curl Converter
Parse Postman Collection v2 JSON and emit curl for up to 10 requests. try/catch JSON.parse.
Open tool
Data formats & conversion
-
JSON Formatter & Validator
Pretty-print JSON and surface syntax errors.
Open tool -
HTML to Markdown Converter
Convert HTML tags to Markdown.
Open tool -
JSON to YAML Converter
Validate JSON in the browser and dump YAML with 2 or 4 space indent.
Open tool -
JSON Formatter and Minifier
2-space, 4-space, tab, or compact JSON with auto-fix and line/column errors.
Open tool -
String Escape / Unescape Tool (JS, Python, SQL, HTML)
Escape or unescape a string as a JS string literal or HTML entities.
Open tool -
SQL Query Formatter & Indenter
Uppercase common SQL keywords and put each on its own line.
Open tool -
Basic SQL INSERT to JSON Converter
Turn a simple INSERT or col=val lines into a JSON object. Not a full SQL parser.
Open tool -
JSON to CSV / Excel Converter
Flatten a JSON array of objects into a CSV table with a header row.
Open tool -
CSV to JSON Array Converter
Parse a header row plus data rows into a JSON array of objects.
Open tool -
XML to JSON Converter
Walk XML tags with DOMParser and emit a nested JSON object.
Open tool -
Flat YAML to JSON Converter
Convert flat key: value YAML lines into a JSON object. Nested YAML is out of scope.
Open tool -
HTML Table Code Generator from Text/CSV
Turn CSV rows into a <table> with a header row of th cells.
Open tool
Encoding & security
-
Base64 Encoder / Decoder
UTF-8 and emoji-safe encode/decode, Standard or URL-safe, with byte telemetry.
Open tool -
JWT Decoder
Inspect header, payload, exp/nbf status, and alg none without uploading the token.
Open tool -
JWT Token Generator & Signer Mock Tool
Build a header.payload token and optionally HMAC-SHA256 sign it in the browser.
Open tool -
Hash Generator (MD5, SHA-1, SHA-256, SHA-512)
Hash text to hex with SHA-1 / SHA-256 / SHA-512 via SubtleCrypto, plus a compact MD5.
Open tool -
HMAC Signature Generator & Validator
HMAC-SHA256 hex of a message plus an optional expected-hex match check. Generic HMAC, not webhook-specific.
Open tool -
Webhook Payload Signer & HMAC Inspector
Sign a webhook-style payload with HMAC for provider examples. Not a generic HMAC playground.
Open tool -
Random API Key & Secret Token Generator
Generate a hex or base64url token from crypto.getRandomValues.
Open tool
Frontend & CSS
-
CSS Box-Shadow Generator
Live preview and copy-ready CSS.
Open tool -
CSS Gradient Generator
Linear and radial gradients.
Open tool -
CSS Minifier & Optimizer
Strip comments, shorten hex, and see original vs minified bytes saved.
Open tool -
CSS Grid Layout Code Builder
Generate grid-template-columns, rows, and gap CSS from column and row counts.
Open tool -
CSS Flexbox Layout Code Generator
Build flex-direction, justify-content, align-items, and gap CSS.
Open tool -
CSS Clamp() Responsive Font Calculator
Preferred vw slope between two viewports, then a clamp(min, preferred, max) string.
Open tool -
CSS Triangle Code Generator
Border-trick triangle CSS from direction, size, and fill color.
Open tool -
CSS Filter Generator (Blur, Sepia, Grayscale)
Compose a CSS filter from blur, sepia, and grayscale sliders.
Open tool -
CSS Keyframe Animation Generator
Emit @keyframes plus an animation rule that rotates from one angle to another.
Open tool -
SVG Path Visualizer & Optimizer
Count path commands, measure string length, and strip extra spaces from a d attribute.
Open tool -
SVG Icon Code Sanitizer & Inline Converter
Strip script tags and on* attributes from SVG markup for safer inline use.
Open tool
Developer utilities
-
UUID / GUID Generator
Generate version-4 identifiers.
Open tool -
Color Code Converter
HEX, RGB, and HSL conversion.
Open tool -
Binary / Decimal / Hexadecimal Interconvertible Calculator
Convert a non-negative integer among binary, decimal, and hexadecimal in the browser.
Open tool -
Data Transfer Speed & Download Time Calculator
Time to move a file from size and a link speed in Mbps, with overhead you can set.
Open tool -
Bandwidth / Bitrate to File Size Estimator
File size from video or audio bitrate and duration, in MB and GiB.
Open tool
Web, HTTP & network
-
URL Encoder / Decoder
Percent-encode and decode URLs.
Open tool -
Meta Tags Generator
Open Graph and Twitter Card tags.
Open tool -
Robots.txt Generator
Allow, disallow, and sitemap URL.
Open tool -
SSL / TLS Certificate Expiry Calculator
Days remaining from notBefore and notAfter dates. Does not decode a certificate file.
Open tool -
IP Subnet & CIDR Calculator (IPv4 / IPv6)
IPv4 network, broadcast, host count, and mask from an address and prefix length.
Open tool -
IP Address to Hex / Binary / Integer Converter
Convert a dotted IPv4 address to hex, 32-bit binary, and unsigned integer.
Open tool -
Port Number Lookup & Common Services Guide Tool
Map a TCP/UDP port to a common service name and IANA range class.
Open tool -
HTTP Header Parser & Format Validator
Parse Name: value lines, count fields, and flag lines that lack a colon.
Open tool -
HTTP Status Code Lookup & Response Explainer
Reason phrase and class for common HTTP status codes.
Open tool -
User-Agent String Parser & Device Inspector
Heuristic browser, OS, and device class from a User-Agent string.
Open tool -
CSP (Content Security Policy) Header Builder
Assemble a Content-Security-Policy header from default-src, script-src, and style-src.
Open tool -
CORS Header Generator
Emit Access-Control-Allow-* response headers from origin, methods, and credentials. No network test.
Open tool -
Cookie String Parser & Attribute Visualizer
Split a cookie header into names and values, treating flags without = as attributes.
Open tool
DevOps & configuration
-
Cron Expression Generator
5-field crontab builder, English explanation, and next 5 local run times.
Open tool -
HTACCESS Rewrite Rule Generator
Emit a RewriteRule from a from-path, to-path, and optional 301 flag.
Open tool -
Nginx Server Block Configuration Builder
Build a listen-80 server block with root, try_files, and optional PHP-FPM.
Open tool -
Unix File Permission (Chmod) Octal Calculator
Build a chmod octal and rwxr-xr-x symbolic string from owner, group, and other bits.
Open tool -
Git Command Cheat Sheet Builder
Common git commands for commit, branch, rebase, stash, or undo tasks.
Open tool -
SemVer (Semantic Versioning) Range Matcher
Test whether 1.2.3 satisfies ^, ~, >=, or an exact version range.
Open tool
Regex & text debugging
-
Regex Tester
JavaScript regex flags, match table with groups, presets, and a 20k ReDoS cap.
Open tool -
Keycode / Keyboard Event Code Inspector
Show charCode, hex, and a Key* guess from a typed character.
Open tool -
String Byte Length Calculator (ASCII vs UTF-8 vs UTF-16)
Count Unicode characters, UTF-8 bytes via TextEncoder, and UTF-16 code units times two.
Open tool
More in Developer & Webmaster
-
SKILL.md / AGENTS.md Structure Checker
Check a SKILL.md or AGENTS.md file against published frontmatter, length, and path rules.
Open tool -
DNS Record Parser (Raw Zone Line)
Split a pasted zone line into name, TTL, type, and rdata. Does not query live DNS.
Open tool -
Basic Markdown to HTML Converter
Tiny Markdown subset: headings, bold, emphasis, inline code, and line breaks.
Open tool -
Basic Curl to Fetch Converter
Turn a simple curl -X -H -d command into a fetch() call. Not a full curl parser.
Open tool -
Line Set Comparison Inspector
Count added and removed lines and list lines that appear in only one side. Not an ordered diff.
Open tool -
Regex Match Highlighter
Run a RegExp against a haystack and list match count plus the first 10 hits. No pattern AST diagram.
Open tool -
Package.json Version Range Cleaner
List dependency names and emit JSON with ^ and ~ stripped from versions. Not a dependency tree.
Open tool -
This-Origin Web Storage Inspector
List keys from window.localStorage or sessionStorage for this site origin only.
Open tool
Explore other categories: Finance & Money , Social & Creators , Daily Utilities and Image & Design