Base

Base is an Ethereum Layer 2 network launched by Coinbase in August 2023. It's built on the open-source Optimism OP Stack, which means transactions land on Base's L2 first and periodically settle to Ethereum L1 via the OP Stack's withdrawal bridge. Base shares Ethereum's security model at a fraction of the cost.

For LearnCoin, Base is the anchoring target. Every credential batch's Merkle root is written to a single Base transaction. Per-credential anchoring cost at scale is effectively zero — a 10,000-credential batch is one transaction. Verifiers walk the Merkle path from the credential's canonical hash up to that on-chain root via basescan.org.

Why Base specifically, as opposed to Ethereum L1, Bitcoin, or another L2: economics (anchoring on L1 at 20 gwei is expensive), settlement finality (OP Stack settles to Ethereum, which is the canonical trust substrate), Coinbase's regulatory posture (Base is institutionally credible), and ecosystem alignment (Farcaster, major DeFi, institutional stablecoin issuers all run on Base). The choice is documented in ADR-003.

LearnCoin contributes Base chain support upstream to the Blockcerts libraries — lds-merkle-proof-2019 and explorer-lookup both now recognize blink:base:sepolia:<tx> and blink:base:mainnet:<tx> anchor codes.