Daylight saving changes for any IANA time zone and year - exact UTC moment, offset before and after, direction, local time and the next transition
IPv6 address tool - expanded and compressed forms, address type, private check, reverse DNS name and for a prefix the range, size and /64 subnet count
Unix chmod calculator - octal to symbolic and back, what owner, group and others can do, umask equivalents and warnings for setuid and world-writable modes
Profile CSV text - detected delimiter, per-column type, nulls, unique counts, min, max, mean, median, top values, duplicate rows and ragged rows
Depreciation schedule for an asset - straight-line, declining-balance with any factor or sum-of-years digits, with yearly expense and book value
Translate text to Morse code with the NATO phonetic spelling, or decode Morse back to text, with counts of symbols and unsupported characters
Generate a QR code from text or a URL - SVG, base64 data URI, ASCII art and the raw module matrix, with error correction level, colors and quiet zone
Screen English text for toxicity - 0 to 100 score and label, matched profanity, insults, harassment, threats and self-harm encouragement, plus shouting
Redact personal data and secrets from text - emails, phones, Luhn-checked cards, IBANs, SSNs, IPs, wallet addresses, API keys, JWTs and private keys
Validate identifiers by check digit - ISIN, CUSIP, SEDOL, LEI, ISBN, EAN or UPC, IMEI, VIN, ORCID, ISSN, NPI, DOI and cards, or auto-detect the type
Locale facts from CLDR for a BCP 47 tag - language, region and script names, text direction, week start, calendar, plural rules and format samples
Format one number across locales - decimal, currency, accounting, percent, compact, scientific and ordinal category for up to 8 locale tags
Password strength estimate - entropy bits, 0 to 4 score, offline and online crack time, common password and pattern penalties, with suggestions
Compare two JSON documents - every added, removed, changed or retyped path with old and new values, plus a summary count by operation
Exact combinatorics with big integers - factorial, nPr, nCr, combinations with repetition, derangements and Catalan numbers for n up to 2000
Analyze a Cache-Control header - browser and CDN freshness, no-store and no-cache handling, stale-while-revalidate and conflicting directive warnings
Convert an IPv4 start and end address into the minimal list of CIDR blocks, with the first and last address and size of each block
MIME type lookup from mime-db - content type for a file extension, extensions for a type, charset, compressibility and IANA source, or search by term
Check a top-level domain against the IANA root zone - exists or not, ccTLD, gTLD or IDN type, RDAP server URLs and the current TLD count
OECD statistics via SDMX - CPI inflation by country preset or any dataflow and key, with named dimensions, units and the latest observation
NWS Area Forecast Discussion by forecast office - the meteorologists' own reasoning, key messages, near and long term outlook, aviation and marine sections
NOAA SPC severe weather outlook at a coordinate - risk category for days 1 to 3 and day 1 tornado, damaging wind and large hail probabilities
SEC EDGAR full-text search for a phrase, optionally by form type and date range - company, form, filing date, period, SIC, location and document link
Paper impact for PubMed IDs from NIH iCite - citations, Relative Citation Ratio, NIH percentile, expected rate, clinical flags and translation potential
