Base’s Cobalt upgrade introduces gas sponsorship and transaction batching in September

Base, the Ethereum Layer 2 network built by Coinbase, is preparing its next major protocol upgrade for September 2026. Called Cobalt, the upgrade will embed native account abstraction directly at the protocol level, bringing gas sponsorship, transaction batching, and session keys to the chain without relying on external tooling.

What Cobalt actually changes

The headline features are gas sponsorship and batch calls. Gas sponsorship means someone other than the user, like a dApp developer or a protocol, can pick up the tab for transaction fees. Transaction batching lets users bundle multiple operations into a single transaction, cutting costs and reducing the number of confirmations needed.

Session keys round out the trifecta. These allow users to grant temporary, limited permissions to applications without handing over full wallet control.

The ERC-4337 standard has offered account abstraction features for a while now, but it works as an overlay, a layer of middleware that sits on top of the existing protocol. Cobalt’s approach is fundamentally different because it integrates smart accounts as a core protocol feature. Applications that previously needed to integrate with bundler services and paymasters through ERC-4337 can now access these capabilities through the protocol itself.

Building on Beryl’s foundation

Cobalt follows the Beryl upgrade that activated on June 25, 2026, which introduced the B20 native token standard and reduced ETH withdrawal times to 5 days.

Cobalt plans to build on the B20 standard with additional functionalities. The upgrade will also introduce a unified node binary that combines both consensus and execution clients into a single package. Developers will need to update nodes and enable new RPC methods for compatibility with Cobalt’s features.

The AI agent angle

Base has been positioning itself as infrastructure for autonomous AI agents, and Cobalt fits into that narrative. Native gas sponsorship means agent operators can fund transactions without requiring each agent to hold its own gas tokens. Session keys provide scoped permissions that let agents act within defined boundaries. Batching keeps transaction counts and costs under control.

What this means for investors

As of mid-July 2026, there have been no significant market reactions or new token announcements related to the Cobalt upgrade. Most competing L2s still rely on ERC-4337 or similar overlay approaches for smart account functionality, making native account abstraction a potential differentiator for Base once the upgrade goes live.

Protocol-level changes are harder to roll back than middleware updates. If native account abstraction introduces unexpected edge cases or security considerations, the consequences are more severe than they would be with an overlay approach that can be patched independently.

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