Here's what Claude said: That works — bip_utils has native eCash support, and the address format checks out (ecash:qq...). I tested it against the standard public BIP39 test vector, not a real wallet, and it derived correctly. A few things worth knowing about why this trips people up: eCash uses SLIP-44 coin type 899. Most generic multi-coin libraries only know Bitcoin (0), Bitcoin Cash (145), or Ethereum-family paths — they don't have 899 registered, so they either error out or (worse) silently give you a Bitcoin Cash address that looks similar but isn't the same account. The derivation path that matches Cashtab / Electrum ABC is m/44'/899'/0'/0/0. CashAddr isn't Bech32. The ecash: prefix uses the same checksum scheme as BCH's CashAddr but with a different prefix string baked into the checksum polymod. If a library gives you a bitcoincash: address and you just string-replace the prefix, the checksum will be wrong and wallets will reject it. bip_utils handles this correctly internally.