API testing, JSON/DB/Git utilities, Cloud generators, AI dev tools and more — free, no signup for the basics.
Press a key to see its KeyboardEvent key/code/keyCode values live.
Check if a website is online and see its hosting, WordPress detection, SSL, DNS, SEO and performance.
Compare the execution speed of 2+ JS snippets, run in an isolated Web Worker.
Preview a URL at common device viewport sizes.
Add a duration to a start time and see the resulting date/time.
Build an iOS/macOS Info.plist from common bundle/privacy keys.
Test a pattern against text with live match highlighting and capture groups.
Convert curl commands to fetch/Python/PHP/HTTPie and back.
A browser stopwatch with lap times.
Percent-encode or decode text, component or full-URI mode.
Encode or decode HTML entities.
Pull IPs, domains, URLs, emails, hashes and CVEs out of text, and defang or refang links.
Generate a changelog from commit history.
Convert a URL query string to a JSON object and back.
Automatically detect and decode Base64, hex, URL encoding, gzip and more, layer by layer.
Show the IP address our server sees you connecting from.
Look up domain registration info.
Generate a scannable QR code.
Generate strong random passwords.
Generate passwords, API keys, AES keys, UUIDs, and RSA/SSH key pairs — all client-side.
Generate v4/v7 UUIDs in bulk.
Classic placeholder text for mockups.
Strip empty/whitespace-only lines.
Live character, word, line, and sentence counts.
Check which web platform features your browser supports.
Show your screen/viewport size live.
Build and send HTTP requests, inspect responses, save history.
Searchable file extension <-> MIME type reference.
Burst-test an endpoint to find its effective rate limit.
Build or decode an HTTP Authorization: Basic header.
Fill in {{variable}} prompt templates and preview the resolved prompt.
Searchable reference of every standard HTTP response status code.
Fetch a URL and explain its response headers, with a security-header grade.
Validate a chat completions request or function/tool schema shape.
Decode and inspect JWT header/payload, verify signatures.
Design REST endpoint specs and generate docs/mocks from them.
Compare two API responses and see a structured diff.
Walk through an OAuth2 Authorization Code flow and inspect tokens.
Estimate LLM prompt token count.
Convert an OpenAPI/Swagger spec to a Postman Collection and back.
Run queries against any GraphQL endpoint and browse its schema.
Get a unique inbox URL and inspect incoming webhook requests live.
Continuously monitor an endpoint for uptime/latency via cron.
Convert text to/from 8-bit binary bytes.
Convert text to/from decimal character codes.
Convert text to/from Unicode code points (U+XXXX).
Convert text to/from hex bytes.
Convert text to/from Base32 (RFC 4648).
Convert text to/from Base58 (Bitcoin alphabet).
Convert any file to a Base64 data URI, entirely in your browser.
Convert Base64 to a hex byte string and back.
Binary arithmetic plus a base converter.
Subnet math — network/broadcast address, netmask, host range.
Convert data sizes between bytes/KB/MB/GB/TB, decimal or binary.
AND/OR/XOR/NOT/shift with a bit-level view.
Convert between seconds, HH:MM:SS, and human-readable durations.
Generate an RFC 4193 Unique Local Address prefix for private IPv6 numbering.
Decode a MAC address's bit flags plus a best-effort vendor lookup.
Four common percentage calculations in one place.
Expand a CIDR block or address range into every individual IP address.
Convert between Celsius, Fahrenheit, and Kelvin.
Hex arithmetic/bitwise ops plus a base converter.
Generate random, locally-administered MAC addresses.
Convert IPv4 to its integer/hex form and IPv4-mapped IPv6.
Convert bps/Mbps/etc. and estimate download time.
Generate random TCP/UDP port numbers for dev servers and configs.
Follow a web address through every redirect and see status codes, loops and HTTPS upgrades.
Find the holder, origin AS, announced prefix and BGP neighbours for an IP, prefix, AS number or hostname.
Convert a time between zones with daylight saving handled, and find a meeting hour for everyone.
Calculate the TCP window you need and the real throughput given bandwidth, latency and packet loss.
Searchable list of common TCP and UDP ports and the services that use them.
Convert CIDR, subnet and wildcard masks and generate Cisco ACL lines.
Convert MAC address formats, get the IPv6 link-local address and the Wake-on-LAN magic packet.
Summarize IPv4 and IPv6 routes into the smallest list of prefixes or one summary route.
Evaluate a math expression with a real parser (no eval) — operators, functions, constants.
Randomize the order of lines.
Convert between UPPER/lower/Title/camelCase/snake_case/etc.
Searchable reference of regex tokens, quantifiers, and common patterns.
Reshape a list — trim, dedupe, sort, wrap, and rejoin with any separator.
Normalize an email to its provider-canonical form for deduping.
Plain-text line diff with added/removed highlighting.
Convert text into a URL-safe slug.
Find/replace text with regex and whole-word options.
Sort lines alphabetically, A-Z or Z-A.
Search and copy from a curated set of common emoji, grouped by category.
Random common-English filler text.
Abbreviate words like "i18n" — first letter, middle count, last letter.
Convert between Arabic numbers and Roman numerals.
Remove repeated lines, keep the first occurrence.
Render text as ASCII art by sampling a real rendered font, not a fixed glyph set.
Spell out text using the NATO phonetic alphabet.
Parse a phone number into its E.164 calling code, country, and national number.
Generate secure random tokens/API keys.
Encode or decode Base64 text and files.
Generate sortable, Crockford Base32-encoded ULIDs in bulk.
Generate a live TOTP (RFC 6238) code from a Base32 secret or otpauth:// URI.
Generate MD5/SHA family hashes.
Test CORS behavior of an endpoint.
Hash or verify text with bcrypt, using PHP's native password_hash/password_verify.
Mask the middle of a string for redacting keys/emails in screenshots.
Compute an HMAC from a message and secret key (SHA-1/256/384/512).
Encrypt/decrypt text with common ciphers.
Validate an IBAN's mod-97 checksum and break it into country/BBAN.
Score a password's strength and estimate crack time, entirely client-side.
Generate a BIP39 mnemonic seed phrase (12-24 words) with correct entropy and checksum.
Look up a CVE ID or search by product: severity, CISA KEV status, exploit probability, affected products and references.
Check whether a password appears in known data breaches without sending it.
Find out which algorithm a hash came from, or checksum a file with MD5, SHA-1 and SHA-2.
Read the version and creation time inside a UUID, and generate sortable UUID v7 values.
Score vulnerabilities with CVSS 3.1: base, temporal and environmental scores and the vector string.
Build a Content-Security-Policy and find weaknesses in an existing one.
Show the SHA256 and MD5 fingerprint, type and size of an SSH public key and compare it with another.
Create the integrity attribute and HTML tag for scripts and stylesheets loaded from a CDN.
Create an RFC 9116 security.txt file so researchers know how to report vulnerabilities.
Decode an X.509 certificate or CSR: subject, issuer, validity, SANs, key and fingerprints.
Monitor SSL certificate expiry dates.
Build an AWS IAM policy JSON document.
Carve a VPC CIDR into equal subnets.
Toggle Unix file permissions to build a chmod command.
Build a Terraform variables file.
Parse or build an AWS ARN.
Parse/build S3 URLs (virtual-hosted, path-style, s3://).
Look up AWS/GCP/Azure region codes.
Re-indent Terraform configuration.
Convert a .env file to JSON or YAML and back.
Convert a docker run command into an equivalent docker-compose.yml service block.
Sample event payloads for S3/API Gateway/SNS/SQS/EventBridge.
Convert between plain JSON and DynamoDB AttributeValue JSON.
Build an Apache .htaccess file for redirects, HTTPS, caching, compression and security, with Nginx rules.
Generate a GitHub Actions workflow for Node, Python, PHP, Go, Java, Rust, .NET, Docker or Pages.
Test which versions satisfy an npm-style semantic version range.
Generate a docker-compose.yml.
Build and explain cron expressions.
Generate a Dockerfile for common stacks.
Parse a User-Agent string.
Generate nginx server blocks.
Generate Kubernetes manifests.
Manage and diff .env files.
Monitor site/service uptime.
Build a .gitignore from checklists by language, editor, and OS.
Searchable reference of common git commands.
Visualize and help resolve merge conflicts.
Generate a conventional-commit message.
Find stale/merged branches to clean up.
Build shields.io badges for version, build, licence and downloads and copy them as Markdown or HTML.
Generate release notes from merged PRs.
Generate test email addresses on RFC 2606 reserved domains.
Generate fake names/emails/usernames for testing.
Generate fake phone numbers (US 555 exchange, etc).
Generate Luhn-valid dummy card numbers for sandbox testing.
Generate fake street addresses for testing.
Drag-select and crop an image.
Shrink an image via adjustable JPEG/WebP quality.
Resize an image to exact dimensions.
Preview SVG markup safely (rendered as an image, not injected).
Convert an image to a base64 data URI and back.
Convert an image between formats.
Rasterize SVG markup to PNG or JPEG at any size.
Generate a lightweight inline-SVG placeholder image, no network request.
Turn screenshots into polished images with device frames, gradients, shadows and text.
Turn a code snippet into a styled PNG with themes, window frames and line numbers.
Convert between TOML and JSON/YAML.
Pretty-print and validate XML.
Diff two JSON documents.
Validate, pretty-print, and minify JSON.
Validate and format YAML documents.
Convert JSON to XML, mirroring our XML to JSON Converter's conventions.
Generate realistic sample JSON that follows a JSON Schema, with a repeatable seed.
Convert JSON to CSV with flattening, delimiters and Excel-friendly output.
Generate TypeScript, Go, Java, C# or Python types from sample JSON.
Build a JSON Schema visually from sample data.
Convert XML documents to JSON.
Convert between CSV and JSON.
Validate and preview TOML as JSON.
Test JSONPath expressions against sample JSON.
Convert a common YAML subset to JSON and back.
Convert a Java .properties file to JSON or YAML and back.
Re-indent Firestore security rules.
Convert CSV to a real .xlsx file and back.
Convert between Unix timestamps and dates.
Recover the original URL from a Microsoft Safe Links wrapped link.
Break a URL down into protocol, host, path, query params, and hash.
Build a custom URI scheme deep link.
Build a cross-platform sms: link with a pre-filled message.
Build a Google Play Store link from a package name.
Build an Apple App Store link from an app ID.
Build a mailto: link with subject/body/cc/bcc.
Build a wa.me click-to-chat link.
Follow redirects to the final destination.
Create short redirect links.
WCAG text/background contrast ratio, AA/AAA pass-fail.
Pick a color, see it in HEX/RGB/HSL.
Convert between hex codes and RGB values.
Convert between RGB and HSV/HSB, the model used by Photoshop/Figma color pickers.
Convert between RGB and HSL.
Generate random hex colors (pastel/vibrant/dark).
Convert between standard CSS named colors and hex codes.
Convert between CMYK (print) and RGB (screen) color values.
Browse Tailwind CSS's default color palette.
Browse Google's Material Design color palette.
Build hreflang alternate-language link tags.
Build a sitemap.xml from a pasted URL list.
Build a robots.txt from rule groups.
Build JSON-LD structured data for common types.
Build a canonical link tag.
Read any website's sitemap, see its page structure as a tree and graph, and check titles, meta tags and status codes.
Build sample APNs and FCM push payloads.
Validate a google-services.json against the expected Firebase config shape.
Build a .entitlements file (associated domains, app groups, push, iCloud, etc).
Analyze keyword competitiveness.
Generate all required app icon sizes.
Manage translation strings across locales.
Find high-value ASO keywords.
Generate a mobile app privacy policy.
List files/sizes inside an APK.
Generate app store release notes.
Generate App Store/Play Store metadata.
Re-indent or minify CSS.
Convert a CSS length across px, rem, em, pt, and %.
Format minified JavaScript or compact it, with strings, templates and regex handled safely.
Generate all standard favicon sizes.
Generate harmonious color palettes.
Design CSS @keyframes animations.
Convert between Markdown and HTML.
Design and export CSS gradients.
Design layered CSS box-shadows.
Minify and clean up SVG markup.
Generate head meta/Open Graph/Twitter Card tags.
Generate glassmorphism CSS.
Visually build an HTML table.
Generate neumorphism CSS.
Visually build Tailwind class combos.
Diff two HTML snapshots.
Format and minify HTML markup.
Convert a font file between TTF/OTF and WOFF.
Generate an EAN-13 barcode.
Convert CSV rows into INSERT statements.
Format and beautify SQL queries.
Visualize table relationships.
Build MongoDB queries visually.
Parse INSERT statements into a JSON array.
Analyze a query for potential performance issues.
Generate an ER diagram from a schema.
Pretty-print a MongoDB query/document.
Visualize an EXPLAIN plan.
Diff two schema/query snapshots.
Summarize error rates/patterns in logs.
Pretty-print raw stack traces.
Search and tail uploaded log files.
Annotate screenshots to report bugs.
Parse and summarize crash reports.
