lt (logical time)
Logical time on TON: a monotonic uint64 counter replacing physical timestamps in internal message semantics. The TON equivalent of a Lamport timestamp.
Aliases: logical time, ton lt
lt (logical time) is a TON-specific concept: a monotonic uint64 counter incremented on every transaction inside a shard. It’s the TON equivalent of a Lamport timestamp in distributed systems.
Why it exists
Physical time (utime / Unix timestamp) on distributed nodes is only approximately synchronised (NTP precision). For strict ordering, TON uses lt:
- Every transaction has its own
ltandprev_lt. - Messages inside a transaction are ordered via
created_lt. - lt always increases within an account/shard — no collisions, no “same moments”.
Where you’ll see it
In tonapi / toncenter responses, utime and lt usually sit side by side: utime for UX (“received at 12:34”), lt for deduplication and precise sorting. When paginating an account’s transactions, the correct cursor is (lt, hash), not utime.