Base, Coinbase's Ethereum Layer 2, activated its Cobalt upgrade on mainnet Sept. 30, introducing Validity Transactions—a mechanism that holds signed transactions pending until specified on-chain conditions are met—plus three B20 token standard enhancements.
Validity Transactions allow users to embed conditional logic directly into transaction submission, removing the operational friction of repeated resubmission. Users can specify conditions tied to on-chain state, price thresholds, or block numbers through the `base_sendRawTransactionValidity` API. Base's sequencer evaluates these conditions before inclusion; if criteria are not satisfied within the specified window, the transaction is discarded.
Example: a trader submits a swap executable only if an asset reaches a price floor and before a defined block height. The user selects and signs all conditions; the infrastructure layer handles eligibility determination.
Cobalt marks Base's third upgrade of 2026. The B20 standard modifications address compliance and corporate action workflows: Composite Policies allow token issuers to combine allowlists and blocklists using AND/OR logic, enabling transactions to require simultaneous satisfaction of multiple eligibility conditions (e.g. both KYC and accreditation clearance). Schedule Multiplier Updates enable pre-scheduled changes to an asset's display multiplier—useful for stock splits or similar corporate actions—without altering underlying token balances or transfer mechanics. A 2x multiplier displays 100 raw units as 200 shares at the interface level.
