Tools

Free, no sign-up online tools. Pick one below to get started.

Generators & Converters

• QR Code Maker — Generate QR codes from URLs or text.
• WAV to MP3 — Convert WAV audio files to MP3.
• Password Generator — Generate strong random passwords with a strength meter, 100% in your browser.
• Color Converter & Palette Generator — Convert between HEX, RGB, HSL and CMYK, build color-wheel palettes and check WCAG contrast, 100% in your browser.
• CSV Viewer & Converter — Upload a CSV and view it in a sortable, searchable table with a column profile, then convert between CSV and JSON with auto-detected delimiters, quoted fields, embedded newlines and large-file support, 100% in your browser.

Audio & Speech

• TTS Engine — Convert text to speech audio.
• Audio Transcriber — Transcribe audio to text.

Images

• Image Upscaler — Upscale images to higher resolution.
• Background Remover — Remove backgrounds from images.
• Favicon Generator — Create a complete favicon set (16–512px PNGs, multi-size favicon.ico, apple-touch-icon and PWA manifest icons) from an uploaded image or a generated letter design, with live previews, copy-ready HTML markup and one-click ZIP download, 100% in your browser.

Calculators

• Energy Calculator — Calculate energy usage and solar savings.
• Password Entropy Calculator — Estimate password strength with a realistic cracking model: entropy in bits, crack times at real attack speeds, and the weaknesses (words, sequences, repeats, dates, l33t) that drag it down, 100% in your browser.

Developer Tools

• HTTP Status Code Lookup — Search or browse every HTTP status code with a plain-English explanation, common causes and fixes, 100% in your browser.
• JSON Formatter & Validator — Format, minify and validate JSON with exact line/column error locations, a collapsible tree view, key sorting and copy/download, 100% in your browser.
• JavaScript Formatter & Minifier — Format or minify JavaScript with a real parser (Acorn) and code generator (escodegen): syntax validation with line/column errors, auto-detect script vs ES module, configurable indentation, quotes, semicolons, parentheses and comment handling, size/line/function statistics and copy/download, 100% in your browser.
• JSON to TypeScript Converter — Convert JSON to TypeScript interfaces and types with nested objects, arrays, optional-field detection, mixed-type unions, interface/type style and readonly/export options, 100% in your browser.
• Base64 Encoder & Decoder — Convert text to/from Base64 with URL-safe variants, Unicode handling, padding and line-wrap options, plus file ↔ data URI conversion, 100% in your browser.
• UUID Generator — Generate crypto-secure UUID v4, v7 and v1 in bulk (up to 1,000) with case, hyphen and brace options, per-UUID copy, text/JSON/CSV export and a UUID validator, 100% in your browser.
• UUID Validator & Parser — Validate UUIDs against the real RFC 4122 / 9562 rules and inspect every field: version, variant, a colour-coded 128-bit map, decoded v1/v6/v7 timestamps and the node as a MAC, plus bulk validation with duplicate detection and CSV/JSON export, 100% in your browser.
• Unix Timestamp Converter — Convert epoch timestamps to UTC and local dates with auto-detected s/ms/µs/ns units, ISO 8601 / RFC 2822 / SQL formats, a live clock, date-to-epoch conversion, time differences and a log-line parser, 100% in your browser.
• URL Encoder / Decoder — Percent-encode and decode URLs, query strings and parameters with component, whole-URL and form modes, a character-by-character breakdown of what got encoded, query-string-to-JSON and a query builder, 100% in your browser.
• URL Query Parameter Parser — Break any URL into protocol, host, port, path, query and fragment, then inspect and edit every query parameter inline: sort keys, de-duplicate, add/remove/reorder rows, and export as a rebuilt URL, bare query string, JSON, JavaScript object, Python dict or cURL command, 100% in your browser.
• Hash Generator — Generate SHA-1, SHA-256, SHA-384 and SHA-512 hashes of text or files with hex, Base64 and Base64url output, a multi-file hashing table, a hash comparison tool with first-difference detection and an avalanche-effect demo, 100% in your browser.
• Hash Checker — Check a file hash online: paste a SHA-256 or drop a file (hashed locally in your browser with constant memory) and look it up in the hash-check.com database for malware hash lookup and file-integrity signals.
• Markdown to HTML Converter — Convert Markdown to clean HTML with a live split preview, CommonMark and GitHub-Flavored Markdown flavours, a table of contents, a syntax quick reference and copy/download export, 100% in your browser.
• HTML Entity Encoder / Decoder — Convert special characters to named, decimal or hex HTML entities and decode them back, with a live rendered preview, a per-character breakdown, browser-accurate decoding of all 2,125 HTML5 names and a searchable entity reference, 100% in your browser.
• XML Formatter & Validator — Format, minify and validate XML with exact line/column error locations, a collapsible element tree, attribute wrapping and sorting, 100% in your browser.
• IP Address & Subnet Calculator — Calculate CIDR, subnet mask, network & broadcast, usable hosts and the colour-coded binary layout for IPv4 and IPv6, with subnet division, membership checks and step-by-step worked examples, 100% in your browser.
• IPv6 Compression & Expansion Tool — Convert IPv6 addresses between fully expanded and RFC 5952 compressed notation, validate syntax, and inspect every component — the eight 16-bit groups, the 128-bit binary and the address type (link-local, ULA, IPv4-mapped, multicast), with a batch mode and JSON/CSV export, 100% in your browser.
• DNS Lookup & Record Explainer — Look up A, AAAA, CNAME, MX, TXT and NS records (plus reverse IP lookup) via DNS-over-HTTPS with a plain-English explanation of every record, a health check that flags common misconfigurations (CNAME conflicts, MX pointing at IPs, single nameserver, private IPs published) and an SPF/DKIM/DMARC mail-security panel, 100% in your browser.
• DNS Propagation Comparison — Send the same query to Google, Cloudflare and AliDNS resolvers at once and compare their answers side by side — records, TTLs and response times — with stale-cache detection, an optional expected-value mode that marks each resolver match or stale until your change has propagated everywhere, auto re-check every 30s, and copy/JSON export, 100% in your browser.
• Email Domain Security Checker — Check a domain's SPF, DMARC and DKIM records via DNS-over-HTTPS, get a plain-English explanation of every SPF mechanism and DMARC tag, a spoofing-risk score, the SPF DNS-lookup count (the RFC 7208 10-lookup limit that silently breaks SPF) and prioritized fixes to stop your domain being impersonated, 100% in your browser.
• Linux in Browser Beta — Boot a real Debian 12 (bookworm) x86 system entirely in your browser with v86 — CPU, disk and kernel emulated in WebAssembly, with a full working terminal (vim, git, curl, python3, htop), adjustable RAM and save/restore of your VM state between visits. Nothing you type ever leaves your device.
• Linux in Browser — Ubuntu 24.04 Beta — Boot a real Ubuntu 24.04 (noble) 64-bit system entirely in your browser with the v86_64 emulator fork — a true x86-64 kernel and userland emulated in WebAssembly, with a full working terminal, adjustable RAM and save/restore of your VM state between visits. Nothing you type ever leaves your device.
• robots.txt Generator — Build a robots.txt with per-crawler allow/disallow rules, * and $ wildcard paths, sitemap locations and crawl-delay, with a live preview and warnings for the mistakes that actually bite (blocking everything, regex syntax, missing slashes), 100% in your browser.
• Sitemap XML Generator — Build a valid XML sitemap from a list of URLs or a browser crawl, with per-URL lastmod/changefreq/priority, live checks against the 50,000-URL and 50 MB limits, automatic sitemap-index splitting and ZIP download, 100% in your browser.
• Regex Tester — Test regular expressions against sample text with live match highlighting, per-match capture groups, every flag (g i m s u y), a plain-English token-by-token explanation of your pattern, and copy/export of the pattern and matches as JSON or CSV, 100% in your browser.
• Regular Expression Library — Browse, test and copy 36 ready-made regex patterns for common tasks (email-ish checks, dates, log parsing, extraction) with a plain-English explanation of what each pattern matches and where it breaks down, live match highlighting on your own text, capture-group tables, JSON/CSV export of matches and a full-library JSON download, 100% in your browser.
• cURL to Code Converter — Paste a cURL command and get runnable code for Python (requests & urllib), JavaScript (fetch), Node.js, Go, PHP, Ruby, Java, PowerShell, cURL and raw HTTP, preserving headers, request bodies, authentication, cookies, redirects, TLS and proxy options, 100% in your browser.
• Semantic Version Calculator — Compare versions to see which is newer (with the exact deciding field), sort release lists, check versions against semver ranges (^, ~, x, hyphen, comparators, ||) with a plain-English expansion, and step through prerelease ordering rules, 100% in your browser.
• Port Number Lookup — Look up any TCP/UDP port to find the service, typical use and security considerations, or search by service name and keyword; includes a filterable reference table, risk ratings and CSV export, 100% in your browser.
• Cron Job Timezone Converter — Convert scheduled cron times between time zones with daylight saving changes accounted for: plain-English schedule explanation, next runs in both zones with DST-shift markers, a reverse solver that finds the server cron time for a target local time (with a CRON_TZ line), and text/CSV export, 100% in your browser.
• .env File Validator — Check .env files for malformed lines, invalid keys, duplicate keys, missing values, CRLF/BOM problems, unquoted secrets and $-expansion traps, with a line-by-line report, an interpolation reference map and a cleaned-file export, 100% in your browser.
• Gitignore Generator — Build a .gitignore for 80+ languages, IDEs, operating systems and project types with a live preview, automatic duplicate removal, custom rules with plain-English syntax explanations, quick-start presets and download, 100% in your browser.
• Git Commit Message Helper — Turn a change summary into a clean, structured commit message: build Conventional Commits (or a custom project style) with live validation, subject-length and imperative-mood checks, type auto-detection, breaking-change rules and git commit export, or lint an existing message, 100% in your browser.
• Chmod Permission Calculator — Convert Linux file permissions between octal (755), symbolic (rwxr-xr-x) and plain-English, with an ls -l preview, ready-to-run chmod commands, SetUID/SetGID/sticky warnings, quick presets and a full octal/symbolic reference, 100% in your browser.
• Linux Command Explainer — Paste any shell command or pipeline and get a plain-English breakdown of every argument, flag, pipe and redirection: built-in notes for 70+ common commands (ls, grep, find, awk, sed, git, docker, curl…), a pipeline visualisation, a safety check that flags destructive operations like rm -rf, dd, mkfs and force-pushes before you run them, JSON export of the breakdown and a shell-syntax reference, 100% in your browser.
• Linux Command Builder — Build copy-ready Linux commands for files, permissions, processes, packages and system administration: pick from 40+ guided recipes (find, grep, chmod, apt, systemctl…), fill in your paths and values, get a live highlighted command with a plain-English explanation of every flag, red safety warnings on destructive operations, quick-fill examples per recipe and a script builder that collects your picks into a downloadable .sh file, 100% in your browser.
• SQL Query Formatter — Beautify SQL with configurable indentation and keyword casing for PostgreSQL, MySQL, SQL Server, SQLite, Oracle and ANSI: dialect-aware tokenizer (TOP, GO, N-strings, backticks, # comments, :: casts, dollar-strings), CTE/subquery indentation, minify mode, syntax-highlighted output, live statistics and sample queries, 100% in your browser.
• SQL INSERT Generator — Convert CSV or JSON records into ready-to-run SQL INSERT statements with correct per-dialect escaping (MySQL, PostgreSQL, SQLite, SQL Server, Oracle): auto-detected format and delimiter, column rename/reorder/drop, per-column type inference and overrides, batched multi-row INSERTs, upsert modes (INSERT IGNORE, ON DUPLICATE KEY UPDATE, ON CONFLICT) and a live problem report, 100% in your browser.
• JSON Diff — Compare two JSON documents structurally: added, removed and changed keys with old and new values, nested JSONPath display, side-by-side and unified views, filterable change list, ignore-array-order mode, type-change detection and copy/export of changed paths, 100% in your browser.
• JWT Decoder & Inspector — Decode a JSON Web Token to inspect its header, claims, expiry times, issuer and signature: formatted header/payload JSON, a plain-English claim inspector with local+UTC timestamps, a security findings panel (alg:none, algorithm confusion, missing/long-lived expiry, signature-size mismatch) and a hex signature dump, 100% in your browser.
• HTML Formatter & Minifier — Beautify messy HTML with consistent indentation, wrapped attribute lists and inline elements kept on one line, or minify for production with size and gzip savings: live parse report with line/column errors (unclosed tags, stray closers, duplicate ids, unquoted attributes), side-by-side original vs processed comparison with scroll sync, 100% in your browser.
• JSON Schema Validator — Validate JSON documents against a JSON Schema (draft-04 to 2020-12) with precise error paths in JSONPath and JSON Pointer, line/column locations that jump to the offending value, $ref resolution, a schema health check for typos and broken references, draft detection and JSON report export, 100% in your browser.
• Open Graph Preview Tool — See exactly how your page looks when shared on Facebook, X (Twitter), LinkedIn, WhatsApp and Slack: live multi-platform previews with each platform’s real truncation limits and image cropping, in-browser image dimension and aspect-ratio checks, a tag validation checklist, paste-your-<head> extraction and ready-to-paste HTML export, 100% in your browser.
• API Request Builder — Build and inspect HTTP requests with methods, headers, query parameters, JSON/form/raw bodies and Bearer, Basic or API-key auth, with a live problem report (invalid JSON, duplicate fields, missing Content-Type) and export as cURL, raw HTTP wire format or JavaScript fetch, 100% in your browser.
• JSON Schema Generator — Generate JSON Schema from one or more sample documents (single JSON, an array of records or JSON Lines) with per-field type overrides, required/optional modes, string format detection (email, date-time, UUID, URI…), numeric bounds, enum suggestions, draft-04 to 2020-12 versions and a built-in self-check that validates your samples against the generated schema, 100% in your browser.
• Wget and cURL Command Builder — Build copy-ready wget or cURL download commands with request headers, basic/Bearer/API-key auth, output file and directory options, retries, retry delays, timeouts, resume, rate limits and custom User-Agents, plus a paste-to-parse mode that breaks an existing command back into its flags and a batch builder that turns a list of URLs (pasted or from a local .txt file) into a ready-to-run shell script, 100% in your browser.
• HTML Meta Tag Generator — Build copy-ready title, description, canonical, robots and viewport tags with live Google-style SERP previews (desktop + mobile), pixel-accurate length checks against real display limits, a validation report that flags the mistakes that quietly hurt (noindex on live pages, canonicals with query strings, zoom-disabled viewports) and per-tag copy or download, 100% in your browser.
• HTTP Request Header Analyzer — Paste any HTTP request headers (raw capture or a cURL command) and get a plain-English breakdown of caching, content negotiation, authentication and security fields, with findings for risky patterns (Basic auth in transit, Referer query leaks, credentials over plain HTTP, end-of-life clients), sensitive values masked by default, a searchable header reference and Markdown/JSON report export, 100% in your browser.
• Security Headers Checker — Check a website’s six security headers (CSP, HSTS, X-Frame-Options, X-Content-Type-Options, Referrer-Policy, Permissions-Policy) via a live browser probe or a pasted curl/DevTools capture, with an A+–F weighted score, plain-English explanations of every finding, the exact weak values flagged (1-day HSTS windows, CSP ’unsafe-inline’), copy-ready recommended headers, fix snippets for nginx, Apache, Django and Express, and Markdown/JSON report export, 100% in your browser.
• Certificate Signing Request Decoder — Decode a CSR (PKCS#10) to inspect the subject DN, public key details (RSA modulus and exponent, EC curve, Ed25519), every requested domain from the Subject Alternative Name extension, the signature algorithm, plus findings for the mistakes that break deployments (missing SANs, weak RSA keys, deprecated algorithms) and a JSON report export, 100% in your browser.
• Subresource Integrity Generator — Generate SRI hashes for JavaScript and CSS assets: SHA-256/384/512 digests from pasted code, a fetched URL or an uploaded file (Web Crypto, in your browser), copy-ready integrity attributes and script/link tags with key-rotation-friendly combined values, plus a verifier that checks an existing integrity attribute against the asset it claims to protect, 100% in your browser.
• Browser Terminal (Dev Playground) — An interactive terminal that runs entirely in your browser: a shell-style prompt with command history plus instant dev utilities — SHA-256/384/512 hashing (Web Crypto), base64 encode/decode, unix timestamp conversion, UUID generation, date and echo — no SSH, no WebSocket, no server-side shell, 100% in your browser.
• OpenAPI / Swagger Viewer — Upload or paste an OpenAPI 3.x or Swagger 2.0 spec (JSON or YAML) and explore the whole API: operations grouped by tag with parameters, request-body samples and response codes, per-operation authentication requirements, every schema resolved out of $ref chains with generated sample values, and copy-ready cURL examples, 100% in your browser.
• GraphQL Query Builder — Build and tidy GraphQL queries, mutations and subscriptions with live syntax highlighting and a real parser (line/column errors), variable tracking against your JSON with one-click auto-fill from declared types, fragment cross-referencing, depth/field complexity stats, comment-preserving formatting, minification and copy-ready cURL, fetch() and GET-URL exports, 100% in your browser.
• Firewall Rule Planner — Plan and audit proposed firewall rules before you apply them: organise allow/deny rules by source, destination, protocol and port with automatic overlap, shadowing, duplicate and redundancy detection, plain-English flags for overly broad access (any-source allows, internet-exposed SSH/RDP/database ports) and export as text, CSV, JSON or iptables / nftables / pf snippets, 100% in your browser.