# OJA Coin Smart Chain (OJX20)

**What is OJA Coin Smart Chain?**

OJX Smart Chain brings EVM-compatible programmability and native cross-chain communication with OJX Smart Chain using an innovative consensus of [Proof of Authority(PoA)](https://docs.ojxscan.com/smart-chain/guides/concepts/consensus.html)

**Why is OJA Coin Smart Chain Chain designed as a separate chain from OJA Coin Main Chain?**

The execution of a Smart Contract may slow down the exchange function and add non-deterministic factors to trading. Even if that compromise could be tolerated, it might be a straightforward idea to introduce a new Virtual Machine specification based on Tendermint, based on the current underlying consensus protocol and major RPC implementation of OJX Smart Chain. But all these will increase the learning requirements for all existing dApp communities, and will not be very welcomed.

**How does OJX Smart Chain work? What is the architecture and consensus used?**

OJX Smart Chain relies on a system with Proof of Authority (PoA) consensus that can support short block time and lower fees.

There will be fewer validators on OJX Smart Chain testnet.

**Can you tell more about Proof of Staked Authority(PoSA)? What is it?**

[PoSA](https://docs.ojxscan.com/smart-chain/guides/concepts/consensus.html) is a combination of PoA and PoS. Blocks are produced by a limited set of validators, they are elected in and out based on a staking based governance. Validators take turns to produce blocks in a PoA manner

**What are the benefits for developers to build on OJX Smart Chain?**

* EVM-compatible: OJX Smart Chain supports all the existing Ethereum tooling Fast block time, cheaper cost
* Native cross-chain trasfer & communication: OJX DEX remains a liquid venue of exchange of assets on OJX Smart Chain and OJX Smart Chain"

**What are the benefits for developers to build on OJX Smart Chain?**

OJX Smart Chain opens the gate for users to take advantage of the fast transferring and trading

**What make OJX Smart Chain different?**

Key Innovations:

* Proof-of-authority Consensus
* Native Cross-Chain Communication
* Expand the use cases of OJX token

**OJX Smart Chain is EVM-compatible. What does that mean?**

EVM means Ethereum Virtual Machine. Any smart-contract written to run in EVM can be easily ported to OJX Smart Chain.

**Can developers make hybrid Dapps using both OJX Smart Chain and OJX Smart Chain in one single Dapp?**

Yes, with the help of native cross-chain functions

 


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