Greek Atbash cipher

This capability takes a non-empty text field, returns the transformed string with counts of mirrored Greek letters and non-Greek passthrough characters, and rejects empty input with a clear invalid_input error.

How Greek Atbash works and what the response contains

Greek Atbash mirrors each of the twenty-four Greek letters by position in the classical alphabet order. Uppercase letters from alpha through omega map to omega through alpha; lowercase letters follow the same reflection within their own alphabet so case is preserved. Final sigma is treated as a form of sigma and maps to eta, matching the usual classroom definition that keeps a single twenty-four-letter table. Characters outside those Greek ranges—digits, punctuation, whitespace, emoji, Latin letters, and accented or non-Greek scripts—pass through unchanged so messages keep their shape and spacing, and the response reports them explicitly so you can audit mixed-script input. Send a JSON body with the required string field text set to any non-empty message; aliases input, value, and s are accepted when clients reuse older form names. Empty strings fail immediately with invalid_input because there is nothing meaningful to transform and the product promise is a real substitution result. On success the response includes result with the transformed text, method equal to atbash_greek so downstream code can branch without sniffing shapes, length equal to the input character count, letters_mirrored counting how many Greek letter units actually flipped, non_greek_count counting every unit that was left unchanged, and non_greek_chars concatenating those passthrough units in input order. Identical inputs always produce identical JSON because the path is pure character table lookup with no network, no random seed, and no wall clock. Use non_greek_count when you want to assert that mixed Latin-and-Greek strings still processed correctly without inventing a second mode field.

Encode, decode, validation rules, and common pitfalls

Missing text, non-string text, or an empty string all raise invalid_input and are not charged on the prepaid API. Whitespace-only strings that still have length greater than zero are accepted; only Greek letters mirror, so a string of spaces returns itself with letters_mirrored equal to zero and non_greek_count equal to the full length. Latin letters and other non-Greek scripts are not mirrored by this Greek Atbash definition; they pass through so the algorithm stays faithful to the Hellenic monoalphabetic mirror people search for, and they appear in non_greek_chars for inspection.

API usage, pricing, classroom workflows, and practical limits

Call the free in-browser Greek Atbash cipher for puzzle drafting, classical-cipher demos, lecture slides on monoalphabetic substitution in Greek, and one-off checks without writing a one-liner in every language. Support playbooks can reverse lightly obfuscated ticket notes that staff intentionally wrote in Greek Atbash. Pair with Latin Atbash or URL-encoding tools only when a later transport step needs a different alphabet—keep Greek Atbash on its own landing so SEO intent stays sharp and searchers looking for Hellenic alphabet mirroring are not sent to a Latin-only tool. Use the prepaid KIT API when a backend, serverless function, tutoring platform, or SDK needs a stable contract under balance at $0.002 per successful item; validation failures never consume balance after the engine rejects the request. A typical classroom workflow shows students that mirroring the Greek alphabet twice returns the original Greek letters, then contrasts that involution with a true keyed monoalphabetic cipher later in the syllabus, while non_greek_chars makes mixed English-and-Greek worksheet examples transparent. Puzzle sites can precompute Greek answers for display and reveal them on demand with the same endpoint. Authors shipping SDKs can map the result field straight into a copy button while method, letters_mirrored, and non_greek_count make OpenAPI examples self-explanatory. Keep payloads to ordinary text sizes appropriate for a Worker isolate item call; this tool is for messages and snippets, not multi-megabyte binary blobs.