Hedera Consensus Service
A consensus messaging service on the Hedera network that provides low-cost, highly deterministic message submission and ordering, suited to use cases such as verifiable logs and social applications.
Timeline (last 90 days)
Hedera Consensus Service (HCS) costs less than one cent per message and reaches final confirmation in about 3 seconds.
Creating an HCS topic costs about $0.01.
A topic supports an optional memo field and an admin key; if no admin key is set, the topic is permanently immutable.
Topics have a renewal mechanism, and a topic left idle for a long time may need to be topped up.
HCS messages reach consensus in about 3 seconds, obtaining an immutable consensus timestamp and a monotonically increasing sequence number, ensuring all readers see the same order of events with no reorganization window.
The consensus timestamp is a nanosecond-level marker in the format "seconds.nanoseconds", reflecting network consensus order rather than the client's local clock; the sequence number is a monotonically increasing integer starting from 1 within a topic.
Production systems (including iBird) often concentrate messages into a single topic rather than creating one topic per user or per post, in order to reduce economic cost.
All Facts (7)
Hedera Consensus Service (HCS) costs less than one cent per message and reaches final confirmation in about 3 seconds.
50%UnverifiedCreating an HCS topic costs about $0.01.
50%UnverifiedA topic supports an optional memo field and an admin key; if no admin key is set, the topic is permanently immutable.
50%UnverifiedTopics have a renewal mechanism, and a topic left idle for a long time may need to be topped up.
50%UnverifiedHCS messages reach consensus in about 3 seconds, obtaining an immutable consensus timestamp and a monotonically increasing sequence number, ensuring all readers see the same order of events with no reorganization window.
50%UnverifiedThe consensus timestamp is a nanosecond-level marker in the format "seconds.nanoseconds", reflecting network consensus order rather than the client's local clock; the sequence number is a monotonically increasing integer starting from 1 within a topic.
50%UnverifiedProduction systems (including iBird) often concentrate messages into a single topic rather than creating one topic per user or per post, in order to reduce economic cost.
50%