Transpose a note by a (possibly negative) number of semitones. Result is spelled chromatically with sharps, or flats when `preferFlats` is true.

Normalise an address to its canonical form — Ethereum to its EIP-55 checksummed form, bech32 Bitcoin to lowercase (base58check is left untouched as it is case-sensitive). An address that is not a valid address of a known chain is rejected before payment.

Build a chord from a root note and quality (major, minor, dim, aug, maj7, min7, dom7, dim7, half-dim7, sus2, sus4, maj6, min6). Notes are spelled by stacked thirds (C dom7 → C E G Bb). Returns the note names, MIDI numbers and semitone intervals.

Rebase a timecode (or a raw frame count) from one frame rate to another on a real-time basis, so the wall-clock position is preserved. Give a source frameRate plus timecode or totalFrames, and a toFrameRate (with optional toDropFrame). Returns the target timecode, frame count and seconds.

Parse an A1 range like "A1:C10" into its start and end cells (normalized so start is the top-left) and its extent — row count, column count and total cell count.

Bitwise AND across two or more non-negative integers (given as decimal strings, evaluated as arbitrary-precision BigInt). Returns the result in decimal, hex and binary.

Guess which chain an address belongs to from its shape and encoding, without requiring the caller to know it up front. Returns the chain, format and address type, or nulls when nothing matches.

Apply a Unicode normalisation form (NFC, NFD, NFKC or NFKD) to a string. Reports whether the text changed and its length in UTF-16 code units and code points.

Break a string into its Unicode code points, each with its U+ notation, decimal value and UTF-8 / UTF-16 byte layout, plus total byte lengths.

Validate an ISBN-10 (mod-11, trailing X allowed) or ISBN-13 (GTIN mod-10) book number. Length after removing spaces/hyphens selects the scheme.

Decode a MessagePack or CBOR byte stream (supplied as a base64/base64url/hex string) back into a JSON value. A malformed envelope, malformed bytes, or a value that is not JSON-representable is rejected before payment.

Evaluate a mathematical expression with optional named variables — arithmetic, comparison and logic operators plus functions like sqrt, abs, min, max, sin, cos, log, floor, round, etc. A syntax error, an undefined variable, or a non-finite result is a clean 400. The factorial operator is disabled for safety.

Serialize a JSON value into a compact MessagePack or CBOR byte stream, returned as a base64 (default), base64url or hex string, along with the byte length.

List a country's holidays for a calendar year (optionally by state/region, language and type).

Validate a Czech VAT (DIČ) number for a legal entity against the official register. Validity means the subject exists and is live in the VAT (DPH) register.

Find the nearest CSS named color to a given color, by perceptual distance.

Check whether a specific date is a public holiday in a country (optionally by state/region).

Compute the WCAG 2.1 contrast ratio between two colors and whether it passes AA/AAA.

Catch drift when everything still looks green. Check available Apify Actor run history and sampled output for schema drift and unexpected empty results. Additional checks cover HTTP responses, credential validity and available quota. One paid call returns a timestamped verdict and supporting details. A successful run or valid credential does not guarantee useful data. This endpoint checks once; it does not send alerts.

Resolve DNS records for a hostname — A, AAAA, CNAME, MX, TXT, NS, SOA, CAA or SRV. NXDOMAIN or an absent record type returns an empty record set.