Leetspeak Decoder & Detector

Decode leetspeak (1337) back to plain text and score how plausibly leet an input is — built for password-policy-bypass screening, profanity-filter-evasion checks, and log-noise triage.

This is the detection-oriented companion to Leet Speak Converter: that tool encodes/decodes, this one analyses.

What it does

• Decodes the input by reversing common leet substitutions (4→a, 3→e, 1→i/l, 0→o, 5→s, 7→t plus the denser |3→b, |<→k, /\/\→m set).
• Scores each word token: a token is leet-suspect only when it mixes letters and leet-shaped symbols (the p@ssw0rd, h3ll0 shape). Pure digits (phone numbers, IDs) score 0 — they have no letters, so the digits aren't leet.
• Verdict: a 0–100 overall score with a configurable threshold → Likely / Possibly / Not leetspeak.
• Highlights every substitution in the original text and lists each glyph → letter mapping it found.

Use cases

• Catch users bypassing a profanity filter by writing b4dw0rd.
• Audit passwords / usernames that obfuscate banned substrings.
• Filter log noise where attackers leet-ify payloads.