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Overview

The Ethereum Vault Connector (EVC) is the beating heart of modularity and composability in Euler V2. Acting as the primary entry point for all advanced interactions, the EVC empowers developers to build, automate, and orchestrate complex DeFi strategies across multiple vaults—securely and efficiently.

Why the EVC Matters

In Euler V2, the EVC is not just a convenience layer—it's the recommended way to interact with vaults. By mediating all cross-vault operations, the EVC unlocks:

  • Batching: Group multiple actions (deposits, borrows, swaps, repayments, etc.) into a single atomic transaction.
  • Sub-accounts: Create up to 256 isolated positions per wallet, enabling sophisticated risk management and strategy separation.
  • Operators: Delegate control of sub-accounts to trusted contracts or automation bots for advanced use cases (e.g., stop-loss, intent-based trading).
  • Deferred Checks: Temporarily exceed limits or health factors within a batch, as long as all checks pass at the end—enabling powerful workflows.
  • Unified Authentication: The EVC handles authentication, so vaults can focus on authorization and business logic.

Core Concepts

Batching​

The EVC's batching system allows developers to bundle multiple operations—across different vaults and even external contracts—into a single transaction. This not only saves gas, but also ensures that all operations succeed or fail together, maintaining system integrity.

Sub-accounts​

Each user address is granted 256 virtual sub-accounts. These allow for risk isolation, strategy separation, and efficient management of multiple positions—all under a single wallet.

Operators​

Operators generalize the concept of token approvals. By assigning an operator to a sub-account, users can delegate control to automation contracts, keepers, or other trusted parties—enabling advanced automation and intent-based strategies.

Deferred Checks & Atomicity​

The EVC defers solvency and cap checks until the end of a batch. This means you can temporarily violate certain constraints within a batch, as long as everything is healthy at the end. This unique feature enables complex, multi-step workflows that would be impossible in traditional DeFi systems.

Authentication & Authorization​

The EVC authenticates the originator of every action, while vaults retain control over authorization. This separation of concerns keeps the system secure and flexible.

Liquidations​

Liquidations are orchestrated through the EVC, ensuring that all steps—collateral seizure, debt repayment, and reward distribution—are performed atomically and securely.

A key part of this process is the EVC's controlCollateral function. When a borrower's position becomes undercollateralized, the liability (controller) vault can invoke controlCollateral to seize collateral from the borrower's enabled collateral vaults. This function allows the controller vault to withdraw assets from a collateral vault on behalf of the account in violation, typically to repay outstanding debt. From the collateral vault's perspective, this appears as a standard withdrawal/shares transfer, but it is executed under the strict rules and authentication of the EVC.

EVC in the Euler V2 Architecture

The EVC is the connective tissue of Euler V2's modular system. It sits between users (or contracts) and the underlying vaults, enabling cross-vault collateralization, composable markets, and seamless integrations with other DeFi protocols. By standardizing how vaults interact, the EVC makes it easy to build new products, automate strategies, and manage risk at scale.

What Developers Can Do with the EVC

  • Build custom frontends and bots that leverage batching, sub-accounts, and operators
  • Create advanced automation (e.g., stop-loss, auto-rebalancing, liquidation protection)
  • Integrate with other protocols using atomic cross-vault operations
  • Simulate complex transactions before execution
  • Design new market structures and risk management tools

For a full technical reference, see the EVC whitepaper, the EVC repository or the EVC dedicated website.