# What is Mainchain?
Mainchain is the backbone of the Unification Network. It is a Cosmos SDK based chain, and is where WrkChains and BEACONs submit their hashes, and FUND transactions take place.
Mainchain is a public proof-of-stake chain. The core coin used for staking, rewards, and network fees is FUND. The on-chain denomination is
nund(Nano Unification Denomination) which is 10^-9 FUND.
There are currently two live public Mainchain networks, and one private development network:
Launched on 14/05/2020, FUND-MainNet (opens new window) is the live public Unification Main Network.
Launched in Q4 2019, FUND-TestNet (opens new window) serves as the official Unification public Test network, where developers can test WRKChains/BEACONs or third party application such as wallets and block explorers before deploying on MainNet. It also serves as a test platform for Mainchain developers to test updates and new features to the Mainchain code in a live environment.
The Mainchain suite comes with a unified binary:
Daemon"). This binary is used for running the server-side daemon (e.g.
for Validator nodes, seeds, sentries, RPCs etc.), and as a client to interact with the network (e.g. for sending queries
and generating and broadcasting transactions).
Mainchain has been built with the following core Cosmos SDK modules:
x/auth: Accounts and signatures.
x/bank: Token transfers.
x/staking: Staking logic.
x/distribution: Fee distribution logic.
x/slashing: Slashing logic.
x/gov: on-chain governance logic.
x/supply: FUND Coin supply logic
x/params: Handles module-level parameters, which can be modified via governance.
x/crisis: Handles potential network errors during the early days of deployment
x/upgrade: Handles processing software upgrades and associated state migrations
Unification have also developed the following modules for Mainchain:
x/beacon: BEACON hash timestamp submission logic
x/enterprise: Handles purchasing, locking and unlocking of Enterprise FUND
x/wrkchain: WRKChain block hash submission handling