🔄 Tendermint Rounds: Propose, Prevote, Precommit
Understand the three-step consensus process with instant finality
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0 / 5 completed⚙️ Tendermint Consensus Process
Tendermint uses a round-based consensus protocol with four distinct phases: Propose, Prevote, Precommit, and Commit. Each phase requires >2/3 validator agreement to proceed, ensuring Byzantine fault tolerance.
The Four-Phase Protocol
Propose
~1 second
The designated proposer (validator) creates and broadcasts a block proposal to all validators.
Prevote
~1 second
Validators vote on whether they accept the proposal. This is the first voting round.
Precommit
~500ms
After >2/3 prevotes, validators send precommit votes to finalize the block.
Commit
Instant
With >2/3 precommits, the block is committed to the blockchain with instant finality.
🔍 Interactive: Consensus Round Simulator
Watch how Tendermint achieves consensus through the four phases:
Required Quorum
5/7
> 2/3 validators
Propose Phase
The designated proposer (validator) creates and broadcasts a block proposal to all validators.
Duration: ~1 second
Phase Details:
- •Round leader is deterministically selected based on validator stake
- •Proposer creates a block with pending transactions
- •Block is signed and broadcast to all validators
- •Validators verify the proposal (valid transactions, proper format)
Proposer Selection
Tendermint uses a weighted round-robin algorithm to select the next block proposer. Validators with more stake have higher chances of being selected, but all validators eventually get a turn.
Weighted by Stake
Validators with more bonded tokens have proportionally higher chances of being selected as proposer.
Deterministic Rotation
Selection is deterministic and verifiable by all validators. No randomness or centralization.
View Changes
If proposer fails to propose (offline/malicious), the round times out and moves to next proposer automatically.
Safety Guarantees
🛡️ Safety Properties
- ✓Agreement: All honest validators commit the same block at the same height
- ✓Validity: Committed blocks contain only valid transactions
- ✓Finality: Once committed, blocks cannot be reverted
⚡ Liveness Properties
- ✓Progress: Network continues producing blocks as long as >2/3 validators are online
- ✓Timeout: Failed rounds timeout and move to next proposer
- ✓Recovery: Network recovers from temporary partitions automatically
The 2/3 Threshold
Tendermint requires more than 2/3 of voting power to agree at each phase. This ensures that even if up to 1/3 of validators are Byzantine (malicious or faulty), the network can still reach consensus safely.
quorum = ⌈(2n / 3)⌉ + 1
Example: 7 validators → quorum = 5 (71.4%)