Documentation
39 pagesHow each tool works, what its URL parameters do and, where one exists, the public API it exposes.
Guides
Network
9IP Address Lookup
Resolve an IPv4 or IPv6 address to its PTR record, location and registry allocation, in the browser or over the public API.
MAC Address Vendor Lookup
Resolve a MAC address to the organisation that registered its OUI, including block size and address range.
DNS Lookup
Query any of 47 DNS record types against a resolver of your choice, from the browser or the public API.
PCAP Analyzer
Read a pcap or pcapng capture in the browser: every packet decoded from Ethernet to DNS and TLS, TCP problems found by Wireshark's rules, streams followed, and the bytes behind every field.
Port Checker
Check whether a TCP port is reachable on a public host, one port, a range, or the common set.
Sonos Radio Stream Checker
Diagnose why a radio stream URL fails on Sonos S1 or S2, hop by hop, against the real Sonos trust store.
SSL/TLS Server Test
Grade the TLS setup of a server and see every finding behind the grade.
TLD Lookup
Search the root zone by ending, domain or country, see how it breaks down, and read the delegation record of any top level domain.
Traceroute
Trace the network path to a public host and stream each hop as it is discovered.
Telephony
2Caller ID Check
Call a test number and see the caller ID the call arrives with, or that the number is withheld; the call is rejected as busy and never answered.
Phone Number Lookup
Any phone number read against the numbering plans: its country, what its range is for, whether it can exist, and its E.164, international, national, tel: and dialling forms.
Encoding
7Base64 Converter
Encode text and files to Base64, standard or URL-safe, and decode Base64 from data URIs, PEM blocks and wrapped lines back to text or exact bytes.
Code Minifier
Minify JavaScript, CSS, HTML, SVG and JSON in the browser with Terser, csso, html-minifier-terser and SVGO, and leave code that cannot be parsed alone.
Color Converter
Convert a color between HEX, RGB, HSL, HSV and CMYK in modern CSS notation, with alpha, all 148 named colors, a WCAG contrast check and color harmonies.
HTML Encoder
Encode text as HTML entities in named, decimal or hex form, decode entities exactly as a browser reads them, and see where encoding protects against XSS.
JWT Decoder
Read a JSON Web Token: header and claims exactly as written, signature, times in UTC and warnings for expired, not yet valid or unsigned tokens. Nothing is verified or sent anywhere.
Punycode Converter
Convert internationalized domain names to Punycode and back, in domains, URLs and e-mail addresses, with the normalization browsers use and a reason for every name that cannot be converted.
URL Encoder
Percent-encode a value, a query string or a whole URL without encoding it twice, and decode escapes back to UTF-8 text with the position of any error.
Crypto
3Hash Generator
Hash text or a file with MD5, SHA-1, SHA-256, SHA-384, SHA-512, CRC32 and Adler-32 at once, and verify a hash you were given.
Password Generator
Generate passwords, pronounceable passwords and PINs from the browser's cryptographic randomness, and rate typed passwords against common passwords, words and patterns.
UUID Generator
Generate UUIDs of version 1, 4 and 7, derive version 3 and 5 from a namespace and a name, in six formats.
Calculators
6Date Calculator
Measure the time between two dates, or an age to this second, in calendar years, months and days, in total days and in business days.
Number Base Converter
Whole numbers of any size converted between decimal, hexadecimal, binary, octal and any base up to 36, with their bytes in both byte orders and their 8, 16, 32 and 64-bit readings.
Percentage Calculator
Six percentage calculations on one page, from a share of a total to the price before a tax, each with the arithmetic it used.
Subnet Calculator
IPv4 and IPv6 subnets worked out in the browser: network, host range, broadcast address, masks, reverse DNS zones and the IANA address type, and whether another address is inside.
Timestamp Converter
Unix timestamps in any unit, ISO 8601 and email or HTTP dates, each turned into all the others, in any time zone, with the pitfalls of 2038, leap seconds and clock changes flagged.
Unit Converter
Convert length, weight, temperature, area, volume, speed, data storage and data rates in either direction, with the exact definition of every unit.
Text
3Case Converter
Convert text into thirteen cases at once, from Title Case to snake_case, with words split correctly across acronyms, apostrophes and every script.
Lorem Ipsum Generator
Generate placeholder text in paragraphs, sentences or words, from classic Lorem ipsum, Cicero or English, as plain text or HTML.
Word Counter
Count words, characters, sentences, paragraphs and lines, estimate reading and speaking time, and list the most common words.
Validators
3Email Validator
Check the syntax of an email address against RFC 5322 and 5321, and whether its domain accepts mail, without sending any.
JSON Validator
Check whether a document is valid JSON, see the first error with its line and column, and format it without changing a value.
XML Validator
Check whether an XML document is well formed, see the first error with its line and column, and format it without changing its text.
Media
3Apple Music Track Lookup
Resolve an Apple Music track id to its record in the store of a chosen country, in the browser or over the public API.
Deezer Track Lookup
Resolve a Deezer track id to its title, artist, album, duration and position, in the browser or over the public API.
Spotify Track Lookup
Look up a Spotify track by its id in a chosen market. Currently unavailable, because Spotify refuses the requests this site makes.