Forta Firewall on OP Enterprise: a sequencer level screening option, first adopted by Ink

Forta Firewall is now one of the screening options available to chains on OP Enterprise, where each chain can choose its own onchain security and compliance provider. Ink, Kraken's L2, is the first to adopt it.

Firewall screens a chain's transaction flow in real time, flagging unwanted activity before it executes on-chain. Chains opt in to the modules that match their chosen risk and regulatory parameters, from compliance screening such as sanctioned addresses to hack and scam prevention.

Seamless Integration

How it works: On an OP Enterprise chain, the sequencer receives transactions, orders them, and builds blocks. Chains that turn on Firewall place it in that path, before block building.

A transaction arrives at the chain's sequencer and is evaluated in under 10-ms against the modules the chain has enabled, using a combination of rules and detection models. Transactions that are not flagged continue to get included in blocks. Transactions that are, can be filtered out before inclusion. Transactions filtered at this stage do not execute or touch state, so there is nothing to roll back. 

The integration is deliberately light. Because it lives in the sequencer path, applications inherit protection by default: no contract changes, no SDK, no change to how users send transactions, and minimal integration work for the chain team. For an OP Enterprise chain that turns it on, it's a configuration choice.

Ink went first

Ink, which runs on OP Enterprise, prioritized compliance above all else. Firewall on Ink screens for sanctioned addresses and enforces a freeze list at the sequencer, so those transactions are blocked before execution rather than flagged after settlement. As with every deployment, the chain decides which modules are enabled and how they are configured.

Available to any chain on OP Enterprise

A new OP Enterprise chain can launch with transaction screening already in place rather than retrofitting it after an incident, and each chain team picks its desired  compliance provider and modules.  Chains that want screening in place from day one can configure it at launch rather than adding it later. 

Building on OP Enterprise? Request a Firewall demo.

Not on OP Enterprise yet? Learn more here 

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About Forta‍

Forta Firewall is an onchain risk management solution. It screens a chain's entire transaction flow in real time, designed to filter activity a chain has configured it to catch, before execution. Chains opt in to the modules that match their risk and regulatory requirements, from compliance screening (such as sanctioned addresses) to hack and scam prevention. Forta was spun out of OpenZeppelin and is backed by a16z, Blockchain Capital, and Coinbase Ventures.

About Optimism‍

The Optimism Foundation builds programmable financial infrastructure for the onchain economy. Its open-source technology, the OP Stack, is the MIT-licensed, Ethereum-aligned foundation used by more than 30 chains, including Coinbase's Base, World, Kraken's Ink, Bitpanda's Vision Chain and Sony Block Solution Labs’ Soneium. OP Enterprise, its commercial offering, delivers managed infrastructure for institutions and exchanges, with programmable block building, and chain configurable transaction screening options and operational reliability. To learn more, visit optimism.io.