Every Cosmos Appchains uses Tendermint consensus, which is currently maintained by @informalinc as @CometBFT.

But what makes TendermintBFT special? Here's an ELI5 of Tendermint consensus.

1. The problem

Imagine a blockchain as a database server that only stores a single number. Whenever a user sends a number to it, it will update the value after the majority of the node come to an agreement (Read: Consensus).

In a single-node system, this is easily achieved.

In a decentralized world with multiple validators:

• How do they come to consensus?

• What happens if one node record a wrong number?

That's the problem Tendermint solved: the Byzantine-Fault Tolerant (BFT) distributed consensus.

2. How Tendermint works

A node can be in 1 of 2 states:

1. Proposer:

   1. Propose a new block (batch of transactions).

   2. is chosen at the beginning of every epoch based on the stake amount and can't be selected twice in a row.

2. Validator.

How Tendermint works:

1. Proposer proposes a block, say a new value = 1.

2. Validators will send their vote to other nodes (read: Pre-vote).

3. Once 2/3 of the votes are received by a node, the node will send that result to other nodes (read: Pre-commit).

4. Nodes wait for pre-commits from 2/3 of all validators to decide whether to update the value to 1 or reject that block.

As long as > 2/3 of the validators are honest → The system is safe 🛡️

3. Tendermint features

• Low fees

• Instant finality

• Loose synchrony

• Scalability with Appchain Thesis

• Blocktimes ~6s. @Injective_ reduce it to 1.1s while @SeiNetwork make it 0.6s

• Battle-tested & high TPS (During Terra/UST collapse, it still worked perfectly)

4. Tendermint compatibility

Since Tendermint is a generic consensus protocol, any programming languages and applications (read: state machine) can run on top of Tendermint.

5. Who built on top of Tendermint?

• Cosmos Appchains: 50+ on mainnet.

• Ethereum Dapps: dYdX

• Ethereum Layer 2 (Fork of Tendermint): Polygon

• Trusted by exchange: OKX chain, Crypto.com chain, Binance Beacon Chain

• and more!

6. Modification of Tendermint Consensus

• @EvmosOrg built Ethermint = Tendermint + EVM-compatible.

• @PolymerDAO is building zkMint, a ZK-friendly Tendermint consensus engine.

• @anoma's Typhon consensus solves block proposal bottleneck & increases transactions computation speed by parallelization.

Final words, quoting from the Tendermint Whitepaper