Bech32 is the Bitcoin address format beginning with “bc1” that was introduced for Segregated Witness outputs.
Bech32 was specified in Bitcoin Improvement Proposal 173 and designed for native Segregated Witness addresses. Mainnet Bitcoin Bech32 addresses use the human-readable prefix “bc1,” while testnet versions use “tb1.” The format was intended to reduce typing and transcription errors compared with older address encodings.
Older Bitcoin addresses commonly begin with “1” for pay-to-public-key-hash outputs or “3” for pay-to-script-hash outputs. Those formats use Base58Check encoding. Bech32 uses a different character set that avoids visually confusing characters and includes an error-detecting checksum.
Bech32m is a related format introduced for newer witness versions, including Taproot addresses. Therefore, not every modern address beginning with “bc1” is necessarily the original Bech32 type: Taproot uses Bech32m. The original Bech32 format is associated with SegWit version-zero addresses.