Celo is an open platform that makes financial tools accessible to anyone with a mobile phone. To deliver on this goal, Celo takes a full-stack approach developing both the platform and the end-user mobile application together in a tightly coupled manner. By doing so, we surfaced a number of unique and interesting technical problems for achieving a great mobile experience. For example, Celo dramatically lowers the amount of data that light clients need to download to sync with the chain by using a novel PoS protocol that’s combined with SNARK provers that generate small proofs that can be used to verify that a header is part of the chain. Further, stability is critical for our end users. For this reason, Celo is launching with its own algorithmic stable tokens, which can also be used to pay for gas on the network. Finally, user research revealed that our users found public key-based addresses hard to understand and preferred phone numbers instead. Therefore, Celo maintains and verifies a decentralized on-chain PKI that maps hashes of phone numbers to public keys so users can easily find each other.

Marek Olszewski is CTO and cofounder of C Labs; previously cofounder of Locu; Facebook Fellow and MIT PhD dropout.