Concepts

Concept	Notes
Account / Token ID	shard.realm.num, e.g. 0.0.12345.
Transaction ID	SDK form 0.0.x@sss.nnn; Mirror form 0.0.x-sss-nnn. hbar-kit converts for you.
Memo	Free-text on the transfer; how you correlate an order/invoice. Public, not unique.
Tinybar	1 HBAR = 100,000,000 tinybars. All HBAR amounts are bigint tinybars internally.
HTS decimals	Token amounts are smallest-unit integers; divide by 10^decimals to display.
Mirror Node	Public read API for ledger data. hbar-kit reads here; it never signs.