Blockaid Cosigner is a transaction security solution designed for multisig and MPC wallet operators. The product provides transaction validation capabilities to prevent malicious exploits and operational errors before transactions are signed. The solution offers transaction simulation that allows users to preview the onchain outcome of transactions through an interactive graph visualization before signing. This addresses the blind signing problem by providing transaction clarity and visibility into the full transaction flow. Cosigner includes a customizable policy engine that enables organizations to configure granular, label-based security policies to block high-risk transactions. The policy engine provides controls for accountability and management of wallet operations. The product features automated workflow capabilities that enable real-time alerts and actions to secure transactions. Organizations can streamline workflows and respond to security events as they occur. Cosigner integrates with major multisig and MPC wallet providers including Safe, Fireblocks, Squads, and Utila. The solution is built on Blockaid's network that processes over 180 million web3 transactions monthly and has prevented 350 million attacks while securing $193 billion in assets. The product is designed for organizations operating multisig and MPC wallets that require transaction validation, policy enforcement, and operational controls for blockchain transactions.