Celo is a Layer-1, EVM-compatible public blockchain aiming to deliver a global financial ecosystem that empowers consumers to access digital payments with their mobile numbers. The blockchain operates in a carbon-negative manner by utilizing a proof-of-stake consensus mechanism.

The USP of the Celo ecosystem is that it maps an end users mobile phone number to their crypto wallet address, letting them send and receive payments worldwide as quickly as text messaging (SMS). Its unique decentralized address-based identity layer also incentivizes mobile users to participate in the consensus mechanism by helping secure and maintain its network.

As of January 2023, the Celo blockchain has users from more than 150 countries and boasts more than 22 million unique wallets. Its regenerative blockchain ecosystem aims to democratize access to financial services so that more people can participate in and benefit from wealth-generating opportunities.

CELO is the native cryptocurrency of the Celo blockchain and serves many purposes. It functions as the governance token and is used for staking and earning rewards, paying transaction fees, and more.

The Celo blockchain is a fully EVM-compatible blockchain with smart contract functionality, which means that it can support Ethereum-based decentralized applications (dApps). It uses a Byzantine Fault Tolerance (BFT) PoS consensus algorithm, which offers it higher efficiency, throughput, and lower gas fees than Ethereum.

Celos core contracts provide most of the logic within the blockchain to offer it features such as ERC-20 stablecoins, identity attestations, PoS mechanism, and decentralized governance. The Celo blockchain is supported by a decentralized network of validators, full nodes, and light clients (mobile-based).

Validators within the network are responsible for collecting transactions, executing smart contracts, participating in block production, and contributing to the blockchains overall consensus mechanism. Full nodes serve requests from light clients and forward their transactions, earning a percentage of the transaction fees as rewards for their efforts.

Unlike validators, full nodes maintain at least a partial history of the blockchain by transferring blocks of transactions between them. They can leave or join the network at any time without affecting the efficiency of the Celo blockchains operations.

End-user devices that run applications from the Celo blockchain make up light clients. They run an instance of the Celo blockchain software, connect to full nodes to request account and transaction data, and sign and submit new transactions.

Celo was founded in 2017 by a team of people from some of the most established universities, financial institutions, and tech companies, including MIT, Stanford, Harvard, World Bank, US Federal Reserve, Bank of America, Capital One, Google, and GoDaddy. The first testnet launch of the blockchain occurred in July 2019, along with the team providing the open-source code and releasing the Celo Wallet - the official wallet app of the blockchain.

The incentivized testnet competition The Great Celo Stakeoff and validator staking were rolled out in December 2019, when the Baklava Testnet Phase 1.0 went live. The second phase of this testnet went live in January 2020 after discovering and rectifying some critical bugs.

Another testnet version was launched in April 2020, and in the same month, Celos codebase completed a security audit by TrailOfBits. The first Celo mainnet candidate was launched in April as well.

Validator elections and epoch rewards were unlocked in May 2020. This was followed by unfreezing voting rewards and CELO transfers in the same month. A month later, the validator group Censusworks submitted a proposal to change Celos native crypto assets name from Celo Gold (cGLD) to Celo (CELO).