Encode and decode every human-readable identifier defined by NIP-19 — npub, nsec, note, nprofile, nevent, naddr, nrelay — with full TLV (Type-Length-Value) parsing for embedded relays, authors, event kinds, and replaceable-event identifiers.
NIP-19 is Nostr's human-facing serialization for keys, event ids, and pointers. It reuses bech32 from Bitcoin's BIP-173 (not bech32m) — 5-bit repacked payload plus a 6-symbol BCH checksum over the human-readable prefix (npub, note, …). Simple types (npub, nsec, note) wrap exactly 32 raw bytes; the pointer types (nprofile, nevent, naddr, nrelay) wrap a TLV stream so a single string can also carry relay hints (type=1), authors (type=2), and event kinds (type=3, 32-bit big-endian). This tool round-trips all of them locally — the string never leaves your browser.