camt.054 is the *intraday* sibling of camt.053. Where camt.053 is one end-of-day envelope per account per booking date, camt.054 fires one notification per booking event (or per small batch), letting the customer reconcile in near-real-time instead of waiting for the EOD cutover.
The internal structure is similar — <Ntfctn> instead of <Stmt>, but the same <Ntry> / <TxDtls> shape and the same carrier-field catalog. A camt.054 notification typically arrives within minutes of the bank booking the entry, which makes it the right primitive for cash-application automation in receivables and for triggering downstream workflows (e.g. release of a shipment on payment confirmation).
Most banks emit camt.054 *in addition to* camt.053 (not instead of). The 053 stays as the end-of-day source of truth for ledger close; the 054 is the streaming preview.
iso-compliant treats the two messages with the same parser surface — same POST /v1/iso20022/camt.053/parse endpoint accepts either, since the carrier-extraction logic is shared.