Privacy-First Utility Tools
Free, fast, and 100% private tools that run entirely in your browser. No server, no tracking, no data leaks.
JSON Tools
JSON Formatter & Validator
Free online JSON formatter and validator that runs in your browser — beautify, minify, and validate without uploading. Your JSON never leaves this tab.
JSON ↔ YAML converter
Convert between JSON and YAML in your browser with line/column errors. Data never leaves the device.
JSON to TypeScript
Turn a JSON sample into TypeScript interfaces or type aliases in your browser. Data stays on the device.
JSON Minifier
Remove whitespace from JSON and validate in one step—all in your browser. Focused workflow separate from prettifying.
JSONPath evaluator
Run JSONPath queries on JSON in your browser—view matching values or each match’s path. No upload.
JSON Schema validator
Validate a JSON instance against a JSON Schema in your browser—Ajv drafts 07 / 2019-09 / 2020-12. No upload.
XML formatter
Pretty-print or minify XML in your browser with DOMParser validation and a local serializer.
HTML formatter & minifier
Pretty-print or minify HTML snippets and documents in your browser with DOMParser and a local serializer.
TOML formatter & validator
Format TOML and surface parse errors with @iarna/toml in your browser. Copy or download formatted.toml—local only.
.env file editor
Parse, validate, normalize, and merge .env files in your browser. Duplicate keys, POSIX hints, and export lines—copy or download locally.
INI / Java properties ↔ JSON
Convert INI or Java `.properties` text to JSON and back in your browser—sections, comments, and continuations parsed locally.
Text Tools
Markdown table formatter
Align GitHub-flavored markdown pipe tables and optionally sort data rows by column — all in your browser.
AsciiDoc preview
Live AsciiDoc → HTML preview with copy and download — @asciidoctor/core runs entirely in your browser.
Mermaid live editor
Live Mermaid diagram preview with SVG and PNG export — mermaid.js runs entirely in your browser.
Secret Share
Seal text with AES-GCM and a master password. Share a single link where ciphertext and IV live in the URL hash — nothing is stored on a server.
Diff Checker
Compare two texts with character, word, or line diff — side-by-side or inline. Ignore whitespace, swap sides, sync-scrolled panes. 100% local in your browser.
Text statistics
Count words, characters, lines, paragraphs, and rough sentences; estimate reading time from a configurable speed — all in your browser.
Text case converter
Turn phrases and identifiers into camelCase, PascalCase, snake_case, kebab-case, and CONSTANT_CASE using local heuristics — choose one phrase per box or one conversion per line — nothing is uploaded.
Slugify
Build URL- and file-friendly slugs from titles in your browser: Unicode-safe or Latin ASCII folding, hyphen or underscore separators, optional one-slug-per-line — nothing is uploaded.
Sort lines
Sort, reverse, or randomly shuffle lines from pasted text in your browser — optional locale-aware numeric sorting and case rules — nothing is uploaded.
Dedupe lines
Remove duplicate lines from pasted text in your browser — keep first occurrences or sort unique lines with locale-aware ordering — nothing is uploaded.
Find & Replace (batch)
Multiline find and replace in your browser — literal text (with optional case rules) or JavaScript regex with flags; replacement counts and copy — nothing is uploaded.
Lorem Ipsum generator
Create paragraphs, exact word counts, or Markdown-style bullet lists of placeholder Latin in your browser — tunable sentences, optional classic opening, regenerate with Web Crypto randomness — nothing is uploaded.
Whitespace normalizer
Normalize line endings (LF / CRLF), expand tabs to spaces or compress leading spaces to tabs, and strip trailing spaces — all in your browser with live stats — nothing is uploaded.
Levenshtein distance
Compare two strings with classic edit distance (insert, delete, substitute) and an optional dynamic-programming matrix — computed locally in your browser.
Markdown Studio
Live GFM Markdown editor with preview, auto-format, HTML export, and rich-text copy. 100% client-side.
Web Font & Typography Workbench
Pair heading and body fonts, build modular scales, tune variable axes, preview CLS-safe fallbacks, and export CSS — all in your browser.
Developer Tools
GraphQL formatter
Pretty-print or minify GraphQL queries, mutations, and SDL with graphql.js parse/print in your browser.
Port Number Reference
Search a bundled table of common well-known ports by number, service, protocol, and category. Filter and copy values locally with no network calls.
UUID Generator
Generate RFC 4122 version 4 UUIDs and the nil UUID in your browser. Batch up to 500 and copy in one click.
ULID Generator
Create sortable identifiers with an embedded millisecond timestamp. Decode any ULID to UTC, local time, and randomness.
NanoID Generator
Create compact, URL-friendly IDs with adjustable length and alphabet presets—or your own character set. Batch up to 500; all randomness stays local.
Random String Generator
Generate cryptographically random passwords and tokens: pick character classes, exclude ambiguous symbols, require coverage, and batch up to 500 — all in your browser.
JWT Debugger
Decode and inspect JWT payloads in your browser — no upload. Sign test tokens with HMAC; secrets stay on your device.
SVG to JSX
Optimize SVG with SVGO in a Web Worker, then turn it into a React component with camelCase attributes. Everything stays in your browser.
Cron Generator
Build crontab schedules with a visual grid or raw expression. Plain-English explanations and next run times — 100% in your browser.
QR Code Studio
Create and scan QR codes for URLs, text, Wi-Fi, and contacts. Customize colors, error correction, and quiet zone. Export PNG, SVG, or WebP — all in your browser.
Browser Auditor
See what your browser exposes: hardware, WebRTC, canvas/WebGL/audio fingerprints, fonts, and screen — scored locally with no tracking.
Code to Image (Carbon-style)
Turn code into Carbon-style screenshots for docs and social posts. Shiki highlighting, window chrome, and PNG/SVG export — all in your browser, nothing uploaded.
Subnet Calculator
IPv4/IPv6 CIDR subnet math in your browser: network, broadcast, usable hosts, wildcard mask, and binary view — no upload.
Password Strength & Entropy
Measure entropy, zxcvbn strength, and estimated crack times across hardware tiers — 100% offline in your browser.
Multi-Hash & Base64 Factory
Encode text to Base64, hex, URL, and HTML entities; compute SHA-256, SHA-512, SHA-1, and MD5 — all live in your browser. Drop a file for a local SHA-256 checksum.
RegEx Studio
Visual regex tester with live highlights, capture groups, explanations, and code snippets. Runs entirely in your browser.
SQL Formatter Studio
Format SQL for PostgreSQL, MySQL, SQLite, and T-SQL, minify for production strings, and design CREATE TABLE scripts with a visual schema builder — all in your browser.
Cloud Resource Cost Estimator
Compare AWS, Azure, and GCP compute SKUs against your target vCPU and RAM, model SSD/HDD/cold storage, and convert estimates into global currencies — instantly in your browser.
PKI & Certificate Studio
Generate RSA and ECC keys, build CSRs and self-signed certificates, and inspect PEM chains — all locally in your browser.
HMAC & Webhook Verifier
Generate and verify HMAC signatures (SHA-256, SHA-512, SHA-1, MD5) for webhook bodies — hex or Base64, entirely in your browser.
TOTP Generator & Verifier
Generate a Base32 TOTP secret, show an otpauth QR for authenticator apps, watch the live code, and verify codes — all in your browser with Web Crypto.
AES-GCM Encrypt & Decrypt
Encrypt or decrypt text and files with AES-128/192/256-GCM in your browser: hex key, 12-byte IV/nonce, optional AAD, and auth tag — Web Crypto only, nothing uploaded.
RSA key generator
Generate RSA public/private key pairs in your browser with Web Crypto; export PKCS#8 private and SPKI public PEM.
PEM decoder
Split PEM text into labeled Base64 payloads and DER byte lengths in your browser — pairs with PKI and RSA tools.
HKDF & PBKDF2 playground
Derive keys from a passphrase or IKM with visible salt, info, iterations, and hash — Web Crypto in your browser.
curl to fetch converter
Paste a curl command and get JavaScript fetch() code — headers, method, and body preserved. Runs locally; your command never leaves the browser.
OpenAPI snippet validator
Validate OpenAPI 3.x or Swagger 2.0 YAML/JSON snippets in your browser—structural checks with path-level errors. No upload.
JWT test token generator
Generate signed HS256/384/512 test JWTs with auto iat and exp claims in your browser. Secrets stay local — for API debugging only.
Webhook payload formatter
Pretty-print or minify JSON webhook bodies and browse common provider signature headers — all locally in your browser.
User agent parser
Break down HTTP User-Agent strings into browser, OS, device, engine, and bot signals — parsed locally with no external lookups.
MAC address formatter
Normalize MAC/EUI addresses and look up IEEE OUI vendors — colon, hyphen, Cisco dot, and bare hex — fully offline.
CIDR aggregator
Merge overlapping and adjacent CIDR blocks into a minimal route list — IPv4 and IPv6, fully offline.
IP in CIDR checker
Bulk-check IP addresses against an allow/deny CIDR list — IPv4 and IPv6, fully offline.
SemVer calculator
Parse Semantic Versioning 2.0.0 strings, bump major/minor/patch/prerelease, and compare two versions — all in your browser.
Gitignore generator
Combine stack presets into a single .gitignore — languages, frameworks, OS, IDEs, and tools — all in your browser.
docker run to Compose
Paste a docker run command and get a Compose YAML fragment — ports, env, volumes, restart, and more. Runs locally; your command never leaves the browser.
Nginx config formatter
Pretty-print or compact nginx.conf snippets with brace-aware indent. Brace checks, copy, and download—local only.
robots.txt generator
Build robots.txt with User-agent groups, Allow/Disallow, sitemaps, and optional Host — presets plus a live preview, all in your browser.
Sitemap XML formatter
Pretty-print sitemap.xml, count URLs or child sitemaps, and spot duplicate loc entries — all in your browser.
Meta tags generator
Build basic SEO, Open Graph, and Twitter Card meta tags with live HTML preview — all in your browser.
Structured data (JSON-LD)
Build Schema.org FAQPage and Organization JSON-LD with live preview — all in your browser.
Hreflang tags generator
Build alternate hreflang link tags from a locale ↔ URL matrix with live HTML preview — all in your browser.
Luhn checker
Validate card/IMEI-style numbers with the Luhn (mod-10) checksum, compute check digits, and bulk-check lists — educational, fully local.
IBAN validator
Validate International Bank Account Numbers with ISO 13616 MOD-97 checksum and country length checks — format, bulk-check, or compute check digits locally.
E.164 phone formatter
Normalize phone numbers to E.164 with international, national, and RFC3966 formats — validate with libphonenumber metadata entirely in your browser.
Converters
CSV to JSON / HTML / Markdown
Parse CSV in your browser with auto-detected delimiters. Export as JSON (objects or arrays), sortable HTML tables, or GitHub-ready Markdown. Nothing is uploaded.
URL Encoder & Decoder
Encode or decode URL components with encodeURIComponent / decodeURIComponent or encodeURI / decodeURI, and parse full URLs into parts — all locally in your browser.
HTML Entities
Escape and unescape HTML entities (&, <, numeric and named) in your browser — for snippets, attributes, and safe text.
Hex Encoder & Decoder
Convert text ↔ UTF-8 hex in your browser, with a decimal byte view. Accepts spaced dumps, 0x prefixes, and line breaks — nothing uploaded.
MIME Type Lookup
Search a curated table of file extensions and MIME types. Filter by category, copy values, and see common extensions for a MIME string — all offline in your browser.
Percentage Calculator
Percent change, “X is what % of Y”, and tip/tax math — delta, markup, and reverse totals — in your browser.
Big Number Calculator
Arbitrary-precision integer and decimal math — add, multiply, divide, power, sqrt — beyond JavaScript Number limits, in your browser.
Unit Converter
Convert length, mass, temperature, and data-size units — metric, imperial, SI decimal, and binary IEC prefixes — in your browser.
Radix & Base Converter
Convert integers between bases 2–36 — binary, octal, decimal, hex, and custom radices — with BigInt precision in your browser.
Unix timestamp converter
Convert Unix epoch seconds or milliseconds to UTC and local calendar time, or parse ISO and other date strings back to epoch — all in your browser.
Timezone converter
Compare IANA timezones for one instant: offsets, abbreviations, and local wall-clock strings using your browser’s Intl data — no network calls.
Date difference calculator
Measure the duration between two datetimes: exact day/hour breakdown, calendar years/months/days, and totals — all in your browser.
ISO 8601 parser
Parse ISO 8601 date and datetime strings into year/month/day, offsets, week and ordinal dates, and Unix epoch — all in your browser.
CSS Unit Converter & Fluid Type
Convert px, rem, em, vh, vw, and %; build linear clamp() for fluid type; convert HEX, RGB, and HSL — all in your browser with live previews.
Color converter
Convert colors between HEX, RGB, HSL, and OKLCH with a live swatch — all in your browser.
WCAG contrast checker
Check foreground and background colors for WCAG 2.x contrast ratio and AA/AAA pass levels — in your browser.
CSS box-shadow generator
Build layered box-shadow CSS with a live preview and copy-ready declaration — in your browser.
CSS border-radius generator
Tune eight corner radii (horizontal and vertical per corner) with a live preview and copy-ready CSS — in your browser.
CSS animation timing editor
Design cubic-bezier and steps timing functions with a draggable curve preview and copy-ready CSS — in your browser.
Tailwind class merger
Merge conflicting Tailwind CSS utility classes with tailwind-merge — dedupe padding, colors, and responsive variants locally.
CSV schema guesser
Infer column types and simple stats from pasted CSV — integers, numbers, booleans, dates, emails, URLs, and mixed columns — entirely in your browser.
Image Tools
Image Optimizer
Compress, resize, and convert PNG, JPG, and WebP in your browser — no uploads. Shrink file size privately before you ship assets.
Image to Base64
Convert PNG, JPEG, WebP, GIF, and SVG images to Base64 data URLs with MIME type and size estimates — entirely in your browser.
Favicon Generator
Turn a PNG or JPEG into a multi-size favicon.ico plus Apple/Android PNG pack — resized and packaged entirely in your browser.
SVG Minifier
Optimize and minify SVG with SVGO in a Web Worker—safe, balanced, or aggressive profiles with byte savings and live preview. Everything stays in your browser.
Image Metadata Viewer
Inspect image dimensions, camera EXIF, GPS, and IPTC/XMP tags locally with ExifReader — nothing is uploaded.
Barcode Generator
Create Code128, EAN-13/8, UPC-A, and QR barcodes locally. Tune colors and bar size, then download PNG or SVG — nothing is uploaded.