# Euler Docs

> Lend, borrow and build without limits.

## Docs

- [Ecosystem](/ecosystem): The Euler ecosystem is built around a modular DeFi protocol, user interface, and various entities that support development, governance, and adoption:
- [Glossary](/glossary)
- [Euler - The Modular Lending Platform](/lite-paper): By Euler Labs
- [Introduction](/introduction): **Euler V2** represents a significant evolution of the Euler protocol, redesigned from the ground up with modularity, security, and capital efficiency at its core. V2 introduces a novel architecture centered around the **Euler Vault Kit (EVK)**. This kit allows anyone to deploy isolated, customizable lending and borrowing markets for virtually any ERC20 token, moving away from the monolithic pool structure.
- [Batch Transactions](/user-guide/batch-transactions): **Batch transactions** on Euler let you combine multiple actions—like supplying, borrowing, swapping, and more—into a single, atomic blockchain transaction. This feature streamlines complex operations, saves on gas fees, and together with the simulation feature, provides a safer, more predictable user experience.
- [Borrowing Assets](/user-guide/borrowing-assets): ![Figure 1: The Borrow page of Euler](/img/user-guide/general/borrowGeneral.png)
- [EulerEarn](/user-guide/euler-earn): Earn passive yield by supplying assets to **managed vaults** that allocate your deposit across underlying strategies on Euler. This guide walks you through how **EulerEarn** works, how to read a vault page, and how to deposit and withdraw.
- [Creating an EulerSwap Position](/user-guide/euler-swap): EulerSwap's liquidity provision interface guides you through a simple 5-step process to create your liquidity positions.
- [Getting Started with Euler V2](/user-guide/getting-started): Welcome to Euler V2, a flexible and modular platform for decentralized lending and borrowing. This guide will walk you through the initial steps to begin interacting with the Euler ecosystem.
- [User Guide](/user-guide): This site contains user guides for interacting with the Euler V2 protocol via the official app ([app.euler.finance](https://app.euler.finance/)).
- [Liquidation](/user-guide/liquidation): **Liquidation** is a core part of how Euler keeps the protocol safe for everyone. If you're borrowing or using leverage, understanding liquidation is essential—not just to avoid it, but to manage your risk and make smart decisions.
- [Multiply (Strategies)](/user-guide/multiply-strategies): ![Figure 1: The Strategies page of Euler](/img/user-guide/general/strategiesGeneral.png)
- [Understanding Your Portfolio](/user-guide/portfolio): ![Figure 1: The Portfolio page on Euler](/img/user-guide/portfolioHeader.png)
- [Spy Mode](/user-guide/spy-mode): **Spy mode** is an advanced feature that allows you to view the Euler app through the lens of another user. This feature is particularly useful for observing other users' positions, understanding their strategies, or analyzing their portfolio composition.
- [Troubleshooting](/user-guide/troubleshooting): If you encounter a bug or error while using the Euler app, follow these steps to troubleshoot and resolve the problem:
- [Managing Positions](/user-guide/managing-positions): Managing your positions effectively is crucial for maximizing returns and minimizing risks on Euler. This guide provides tips and best practices for managing your positions.
- [Supplying Assets (Lend)](/user-guide/supplying-assets): ![Figure 1: The Lend page of Euler](/img/user-guide/general/lendGeneral.png)
- [Active monitoring](/security/active-monitoring): Euler is closely monitored by top security platforms that oversee all operational networks. These platforms use advanced threat detection and response systems to quickly identify and address potential risks. Their analytical and defense capabilities help keep the protocol secure, enabling quick responses to threats and protecting user assets. Based on the vault's design, the following actions are taken when a threat is detected:
- [Application Security](/security/app-sec): Euler implements a comprehensive application security strategy that protects both the protocol and its users through multiple layers of security measures. This document outlines the various security implementations and best practices in place.
- [Euler Protocol Audits](/security/audits): The protocol has received more than 60 security reviews by 16+ of the world's leading web3 security firms. Find details about all of Euler's security reviews in the table below.
- [Bug Bounty Program](/security/bug-bounty): Euler maintains one of the largest bug bounty programs in DeFi, with **up to $7.5 million available** for critical vulnerability discoveries. This substantial bounty demonstrates our commitment to security and incentivizes the world's best security researchers to help safeguard the protocol.
- [Euler DAO Vaults Governance](/security/dao-vaults-governance): Euler DAO managed vaults use a robust, modular governance framework designed to balance operational flexibility, user protection, and rapid emergency response. This system is built on selector-based access control, dual timelocks, and clearly separated roles for routine, administrative, and emergency actions. The architecture is designed to support optimistic risk management, as described in [EIP-62](https://forum.euler.finance/t/eip-62-optimistic-risk-management-via-timelocked-risk-stewards-and-limited-rapid-response/1225).
- [EulerEarn Audits](/security/earn-audits): The EulerEarn contracts have been audited by multiple leading web3 security firms. Find details about all of EulerEarn's security reviews in the table below.
- [Security Overview](/security/overview): Euler stands as one of the most rigorously and extensively audited DeFi projects in the world. Its [modular architecture](https://medium.com/eulerfinance/modularity-the-way-forward-to-building-defi-systems-35fa95f7329a) isolates risk, makes code easier to test, analyze, and audit, and helps reduce single points of failure. For a detailed overview of the steps taken to secure Euler, you can explore a dedicated blog post on the topic [here](https://euler.finance/blog/securing-euler).
- [Pause and Upgradability](/security/pause-and-upgrade): At the protocol level, the ability to pause and upgrade vaults is entirely optional. This functionality is provided through a vault factory governor smart contract, allowing for flexibility in implementation. For factories that choose to implement these features, the pause function serves as a critical safety mechanism, temporarily halting vaults to read-only mode in emergency situations.
- [SEAL Safe Harbor](/security/seal-safe-harbor): Euler has adopted the [SEAL (Security Alliance) Whitehat Safe Harbor Agreement](https://safeharbor.securityalliance.org/database/euler), a legal framework created by the nonprofit founded by samczsun that empowers ethical hackers to intervene and rescue protocol funds during active exploits.
- [Securitize Audits](/security/securitize-audits): The Securitize integration contracts have been audited by multiple leading web3 security firms. Find details about all of the security reviews in the table below.
- [EulerSwap Audits](/security/swap-audits): The EulerSwap contracts have been audited by multiple leading web3 security firms. Find details about all of Euler's security reviews in the table below.
- [Donation Attacks](/security/attack-vectors/donation-attacks): This scenario illustrates a worst-case hypothetical attack on a lending protocol that relies on exchange rate manipulation of ERC-4626 vaults. Specifically, it focuses on an attack on a lending protocol that lists an ERC-4626 vault as both collateral and a borrowable asset, and uses the vault's exchange rate as an oracle to price the underlying asset.
- [DAO Proposals](/euler-dao/proposals): Any EUL holder with a sufficient balance may create an off-chain proposal for a DAO action via [Snapshot](https://snapshot.org/#/s:eulerdao.eth). These proposals are then voted on by entities delegated by EUL holders. As an EUL holder, you can delegate your voting power on [Tally](https://www.tally.xyz/gov/euler/delegates). Individual EUL holder may delegate themselves in order to participate directly.
- [Treasury](/euler-dao/treasury): The DAO holds EUL tokens in the Treasury. The Treasury is managed by EUL token holders through on-chain and off-chain governance procedures and overseen by the Euler Foundation.
- [New Issuance](/euler-dao/treasury): New EUL tokens can be minted at the discretion of the DAO, at a rate not exceeding 2.718% of total supply per year. The minted tokens enter circulation via the Legacy Treasury, which is also overseen by the Euler Foundation.
- [Getting Started with Euler V2 Development](/developers/getting-started): Welcome to the Euler V2 Developer Portal! This guide will help you set up your development environment and start building on Euler V2. Whether you're creating custom lending vaults, integrating lending capabilities into your dApp, or building yield strategies, this guide will get you started.
- [Developer Guide](/developers): Welcome to the Euler V2 Developer Guide! This section is your comprehensive resource for building on top of or integrating with the Euler V2 protocol. Whether you're looking to create custom lending vaults, integrate lending capabilities into your dApp, or build advanced financial products, this guide will help you get started.
- [Contract Addresses](/developers/contract-addresses): The contract addresses are fetched from the [euler-interfaces repository](https://github.com/euler-xyz/euler-interfaces/tree/master) you can also view them here along with their corresponding ABI and interface files.
- [Factory Contracts in Euler V2](/developers/periphery/factories): Factory contracts are a cornerstone of the modular, composable architecture of Euler V2. They provide a standardized, auditable, and secure way to deploy and manage multiple instances of smart contracts, ensuring that all deployments originate from a single, verifiable source. This makes it easier for developers and auditors to track, upgrade, and govern protocol components at scale.
- [Factory Governor](/developers/periphery/factory-governor): The `FactoryGovernor` contract plays a crucial role in the security and management of the EVK factory. Acting as the `upgradeAdmin`, it gives trusted parties the ability to upgrade, pause, or unpause the factory and, by extension, all upgradeable vaults created by it. This centralized control is essential for emergency responses.
- [Governor Contracts](/developers/periphery/governors): Governor contracts are the backbone of secure, flexible, and upgradeable governance for Euler Vault Kit (EVK) vaults and oracle routers. They enable fine-grained control over vault operations, risk parameters, and emergency responses — balancing the need for rapid intervention with robust user protection.
- [Order Flow Router](/developers/periphery/orderflow-router): The Order Flow Router is a key component of Euler V2's swap and multiply position infrastructure. It acts as an off-chain meta-aggregator and strategy engine, finding the best way to swap assets and building safe, ready-to-use payloads for EVC batch calls. This enables users to open, close, and manage complex positions with a single transaction.
- [Perspectives](/developers/periphery/perspectives): Perspectives are on-chain contracts that encode validity criteria for Euler Vault Kit (EVK) credit vaults. They provide a permissionless, programmable way to verify, filter, and curate vaults based on arbitrary logic — enabling safer, more transparent DeFi integrations and user interfaces.
- [Swaps](/developers/periphery/swaps): Swaps are a core building block of the Euler V2 protocol, enabling users to efficiently manage leverage, rebalance positions, and handle liquidations — all within a single, gas-optimized transaction. This guide explains how swaps work in Euler, the contracts involved, and best practices for secure and efficient execution.
- [Creating and Managing Vaults](/developers/evk/creating-managing-vaults): The Euler Vault Kit (EVK) provides a flexible framework for creating and managing lending vaults. Vaults are created through a factory contract, which deploys a proxy pointing to the implementation contract.
- [Hooks and Custom Logic](/developers/evk/hooks-custom-logic): The [**Euler Vault Kit (EVK)**](./index) provides a flexible hooking system that allows vault governors to extend vault functionality or restrict certain operations. This guide explains how hooks work and provides examples of common use cases.
- [Overview](/developers/evk): **The Euler Vault Kit (EVK)** is a system for constructing credit vaults - [ERC-4626](https://eips.ethereum.org/EIPS/eip-4626) vaults with added borrowing functionality. Unlike typical ERC-4626 vaults which earn yield by actively investing deposited funds, credit vaults are passive lending pools. Users can borrow from a credit vault as long as they have sufficient collateral deposited in other credit vaults. The liability vault (the one that was borrowed from) decides which credit vaults are acceptable as collateral.
- [Interacting with Vaults](/developers/evk/interacting-with-vaults): This guide explains how to interact with [**Euler Vault Kit (EVK)**](./index) vaults programmatically. We'll cover basic operations, advanced features, and best practices.
- [Security Considerations](/developers/evk/security): The [**Euler Vault Kit (EVK)**](./index) is designed with security as a priority, but there are inherent limitations and risks that developers and users should be aware of. This document outlines key security considerations when working with EVK vaults.
- [Supply and Borrow Cap Encoding](/developers/evk/supply-borrow-caps): Supply and borrow caps in the [**Euler Vault Kit (EVK)**](./index) are not stored as plain integers, but are instead encoded using a compact 16-bit decimal floating point format. This allows vaults to efficiently store and process cap values on-chain, while still supporting a wide range of possible limits.
- [EVC Utils Guide](/developers/evc/evc-utils): [`EVCUtil.sol`](https://github.com/euler-xyz/ethereum-vault-connector/blob/master/src/utils/EVCUtil.sol) is a utility abstract contract designed to make it easier and safer to build contracts that interact with the [**Ethereum Vault Connector (EVC)**](./index). It provides authentication helpers, context-aware modifiers, and patterns for enforcing that your contract is always called through the EVC when required.
- [Overview](/developers/evc): **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.
- [Integration Guide](/developers/evc/integration-guide): This guide explains how to integrate with the Ethereum Vault Connector (EVC) in your applications, bots, and smart contracts. You'll learn how to batch operations, use sub-accounts, delegate with operators, perform liquidations, and simulate transactions—all with practical Solidity code examples.
- [Security Considerations](/developers/evc/security): The [**Ethereum Vault Connector (EVC)**](./index) is designed as a foundational layer for secure, modular lending and collateral management. While it provides robust security features, both protocol users and integrators must understand its security model, limitations, and best practices to ensure safe operation.
- [EulerSwap vs. Traditional AMMs](/developers/euler-swap/comparison): EulerSwap’s design contrasts with conventional AMMs in a few notable ways:
- [How EulerSwap Works](/developers/euler-swap/how-it-works): In order to create an EulerSwap pool, you are expected to provide liquidity into Euler’s vaults. Because of this design, your liquidity isn’t idly sitting in a pool; it remains active within the lending market. The same capital simultaneously:
- [EulerSwap: A Capital-Efficient AMM](/developers/euler-swap): **EulerSwap** is Euler's decentralized exchange (DEX) built on top of Euler V2. It introduces an automated market maker (AMM) design where liquidity is directly integrated with Euler’s vaults. This unified approach allows users to earn swap fees and lending yield on the same assets, while enabling advanced strategies like leverage and dynamic hedging.
- [Considerations for Liquidity Providers and Curators](/developers/euler-swap/lp-considerations): Providing liquidity via EulerSwap introduces new opportunities for sophisticated users. Here are key things LPs should keep in mind:
- [Allocator & Manager Handbook](/developers/euler-earn/allocator-handbook): This guide covers deploying an Earn vault and operating it safely and efficiently.
- [Overview](/developers/euler-earn): **EulerEarn** is a non-custodial, ERC-4626 compliant meta-vault that aggregates user deposits into a curated set of underlying lending vaults on Euler (and other ERC-4626 strategies). Users deposit a single asset and Earn allocates it across multiple isolated strategies to optimize yield, while preserving risk isolation per strategy.
- [Integrator Guide](/developers/euler-earn/integrator-guide): EulerEarn vaults are standard [ERC-4626](https://eips.ethereum.org/EIPS/eip-4626) vaults with meta-allocation logic. Users get a simple deposit/redeem experience; integrators get a familiar interface with extras like [Permit2](https://github.com/Uniswap/permit2) and [EVC batching](../evc/integration-guide#1-batching-operations).
- [Overview](/developers/data-querying): Euler V2 provides a modular architecture for accessing, analyzing, and visualizing protocol data. This section covers the technical approaches for extracting data from the protocol, whether you're developing dashboards, bots, risk assessment tools, or conducting research.
- [Lens Contracts](/developers/data-querying/lens-contracts): Lens contracts are specialized, read-only smart contracts designed to make it easy for developers and analysts to access and aggregate protocol data from Euler V2. They provide a convenient way to query on-chain state, combining information from multiple contracts into a single, structured response. Typically, lens contracts are meant for off-chain use only as they are not gas optimized.
- [Querying Off-Chain Prices](/developers/data-querying/off-chain-prices): When building analytics tools, dashboards, or performing off-chain calculations (such as collateral market value), you often need up-to-date asset prices. Euler provides an internal API endpoint that can be used to fetch prices for supported assets.
- [Getting Lists of Verified Vaults](/developers/data-querying/perspectives): Perspectives are on-chain contracts that encode rules for verifying and filtering Euler vaults. They are the primary tool for developers, analysts, and integrators who want to obtain lists of safe, curated, or otherwise trusted vaults for use in dashboards, analytics, or integrations.
- [Working with Pyth Oracles](/developers/data-querying/pyth-oracles): Euler V2 supports pull-based oracles like Pyth, which require special handling compared to traditional push-based oracles. This guide explains how to work with these oracles effectively, both for querying data and executing transactions.
- [Subgraphs](/developers/data-querying/subgraphs): Subgraphs are a powerful way to index and query on-chain data from Euler V2 smart contracts. They allow developers, analysts, and integrators to access protocol data efficiently using GraphQL, without needing to parse events or maintain their own indexing infrastructure.
- [EulerVaults](/developers/data-querying/subgraphs): [Euler Subgraphs GitHub Repository](https://github.com/euler-xyz/euler-subgraph)
- [EulerEarn](/developers/data-querying/subgraphs): [Euler Subgraphs GitHub Repository](https://github.com/euler-xyz/euler-subgraph)
- [EulerSwapPools](/developers/data-querying/subgraphs): [Euler Subgraphs GitHub Repository](https://github.com/euler-xyz/euler-subgraph)
- [Using Lens Contracts](/developers/data-querying/using-lens-contracts): This guide is for developers, analysts, and integrators who want to query protocol data efficiently and make sense of the results. We'll walk through practical examples and explain the key data types you'll encounter.
- [Attack Vectors](/creator-tools/attack-vectors): When creating and managing Euler vaults, it's important to be aware of potential attack vectors and how to prevent them. The following resources provide detailed information about known attack vectors and their mitigations:
- [Deployment & Configuration of Oracle Router](/creator-tools/deploy-oracle-router): **The Oracle Router** is a required component of the Euler protocol. Every vault must be connected to an Oracle Router to obtain reliable, on-chain price feeds for its underlying asset and all accepted collateral. The router enables flexible, modular pricing paths and can be managed either from its dedicated UI page or during vault configuration. It is recommended that all vaults in a cluster share a single router, ensuring consistent pricing and risk management.
- [Governance Contracts](/creator-tools/governance-contracts): Governance contracts are essential for secure, flexible, and upgradeable management of Euler Vault Kit (EVK) vaults and oracle routers. They enable fine-grained control over vault operations, risk parameters, and emergency responses, balancing the need for rapid intervention with robust user protection.
- [Overview](/creator-tools): Euler's modular and permissionless architecture gives developers, builders, and risk curators fine - tuned control over nearly every aspect of the protocol. The Creator Tools empower you to design, deploy, and manage custom financial products within the Euler ecosystem. Whether you're launching credit vaults or earn vaults, designing new governed or ungoverned credit markets, building a new oracle adapter, or deploying an EulerSwap operator, this section provides the essential documentation and tools to bring your ideas to life.
- [Interest Rate Models (IRMs)](/creator-tools/interest-rate-models): **Interest rate models (IRMs)** are a core component of risk management and capital efficiency in Euler vaults. They determine how borrowing and supplying rates respond to changes in utilization. Euler currently supports two main types of IRMs, each with distinct governance and operational requirements.
- [Introduction to Vaults](/creator-tools/vaults): Vaults are the core primitive of the Euler protocol. They serve as modular, composable smart contracts that enable permissionless lending, borrowing, and yield aggregation. Each vault is an isolated pool of assets with its own risk parameters, governance, and configuration, allowing for a wide range of financial products — from simple lending pools to complex, governed credit markets and meta-vaults.
- [Labeling in Euler](/creator-tools/vaults/labeling): Labeling is an important part of the Euler ecosystem, providing human-readable metadata for vaults, entities, and markets. This metadata is used to enhance the dApp UI, making it easier for users to identify vaults, understand governance, and discover new markets.
- [Using the Creator UI to Deploy Vaults](/creator-tools/vaults/evk/creator-ui): Plan your vault architecture and collateral relationships.
- [Deployment and Management of EVK Vaults](/creator-tools/vaults/evk/deployment-and-management): There are three main ways to deploy and manage **Euler Vault Kit (EVK)** vaults, each suited to different users and workflows:
- [Using the Objective Labs Edge UI](/creator-tools/vaults/evk/edge-ui): The Objective Labs Edge UI ([app.objectivelabs.io/edge](https://app.objectivelabs.io/edge)) provides a streamlined interface for constructing and deploying fully immutable lending vaults (Edge Markets) on Euler. While the principles are similar to the standard Creator UI, the Edge UI emphasizes simplicity, revision-based workflows, and the deployment of immutable markets.
- [Cluster Deployment & Management using scripts](/creator-tools/vaults/evk/euler-vault-scripts): The [`euler-vault-scripts`](https://github.com/euler-xyz/euler-vault-scripts) repository provides a robust, script-based framework for deploying, configuring, and managing clusters of EVK vaults. It is the recommended tool for advanced users, DAOs, and protocol developers who need automation and support for complex, governed markets.
- [Euler Vault Kit Introduction](/creator-tools/vaults/evk/introduction): **The Euler Vault Kit (EVK)** is a powerful, modular framework for building credit vaults — permissionless, composable lending pools that form the foundation of the Euler protocol. EVK enables anyone to deploy and configure isolated lending vaults, each with its own risk parameters, governance, and supported assets.
- [Deployment & Management of EulerEarn Vaults](/creator-tools/vaults/euler-earn/deployment-and-management): **EulerEarn** is a fork of MetaMorpho that provides a permissionless, role-based, and immutable way to curate yield strategies on top of ERC-4626 vaults. The recommended way to deploy and manage Earn vaults is via the [EulerEarn Creator UI](https://earn.euler.finance/).
- [Introduction](/creator-tools/vaults/euler-earn/introduction): **EulerEarn** is an open, permissionless protocol for curating and aggregating yield on top of ERC-4626 vaults. It is designed to make passive yield accessible to everyone, while enabling risk curators to manage strategies and allocations transparently and securely.
- [Advanced Features](/creator-tools/maglev/advanced): EulerSwap supports leveraged positions, such as depositing $250k USDC to loop borrow $650k and swap $400k USDT to build a balanced liquidity position.
- [Interface Guide](/creator-tools/maglev/interface-guide): The Maglev interface provides real-time data visualization and interactive controls for pool management:
- [Monitoring and Maintenance](/creator-tools/maglev/monitoring): Monitor Net Asset Value (NAV) relative to the equilibrium price to ensure stability and delta-neutrality.
- [Operational Considerations](/creator-tools/maglev/ops): **For operators, understanding and managing the gap between current price and equilibrium is essential for:**
- [Overview](/creator-tools/maglev/overview): This documentation was authored by [Telos Consilium](https://telosc.com/), a Web3 service provider mandated by the Euler team to create onboarding and educational materials for this product.
- [Overview](/creator-tools/maglev/overview): This documentation was authored by [Telos Consilium](https://telosc.com/), a Web3 service provider mandated by the Euler team to create onboarding and educational materials for this product.
- [Q&A Highlights](/creator-tools/maglev/qa): Custom callbacks and flash swaps are supported for advanced integrations.
- [Technical Specifications](/creator-tools/maglev/spec): **Factory Contract:** Deploys new swap pools with immutable curve parameters.
- [Case Study: Telos Consilium USDT/USDC Stablecoin Pool Deployment](/creator-tools/maglev/use-case): With only **$100k NAV**:
- [Set Fees](/creator-tools/maglev/configuration/fees): Setting swap fees is a critical step when configuring a new EulerSwap pool using Maglev. The fee parameter directly influences the earnings potential for liquidity providers, impacts trader behavior, and plays a role in managing risk and capital efficiency.
- [Select vault pairs](/creator-tools/maglev/configuration/select-vault-pairs): When creating a new pool in EulerSwap using Maglev, the first step is to **select the two assets that will form your trading pair**. These assets must be available within the Euler lending protocol, as liquidity for your pool will be sourced directly from your Euler account balances.
- [Set equilibrium price](/creator-tools/maglev/configuration/set-equilibrium-price): When configuring a new pool in EulerSwap using Maglev, setting the equilibrium price is a critical parameter that fundamentally shapes the behavior of your liquidity pool. This parameter defines the theoretical balance point of your AMM curve and has significant implications for capital efficiency and risk management.
- [Concepts](/concepts): Welcome to the concepts section of Euler documentation. Here you'll find detailed explanations of the core components, mechanics, and design principles that power the protocol. Whether you're new to Euler or looking to deepen your understanding, these guides will help you grasp how everything works together.
- [Liquidations](/concepts/risk/liquidations): **Liquidations** are a crucial safety mechanism in Euler that helps maintain the protocol's solvency and protect lenders' deposits. When a borrower's position becomes undercollateralized, the liquidation process kicks in to ensure that debts are covered and the system remains stable. This process is automated, efficient, and designed to be fair to all participants.
- [Risk Curators](/concepts/risk/risk-curators): **Risk curators** play a vital role in the Euler ecosystem, acting as guardians of protocol safety and efficiency. Their responsibilities vary depending on the type of vault they govern, but their core mission remains the same: to ensure the security and sustainability of the protocol while maximizing returns for depositors.
- [Vault Types](/concepts/risk/vault-types): In the dynamic world of Euler's lending ecosystem, vault types serve as trusted classifications that help users navigate the complex landscape of lending opportunities. These classifications aren't just labels - they're verified through a sophisticated system of smart contracts called 'perspectives' that act as on-chain validators. Think of perspectives as digital inspectors that verify whether a vault, and all the vaults it's connected to through its collaterals, meet specific safety and functionality criteria.
- [Annual Percentage Yield](/concepts/financial/annual-percentage-yield): **Annual Percentage Yield (APY)** is a crucial metric in Euler that helps users understand their potential returns or costs when interacting with the protocol. Unlike simple interest rates, APY accounts for the effects of compound interest, providing a more accurate picture of the actual yield over time. Whether you're supplying assets to earn yield or borrowing assets to access liquidity, understanding APY is essential for making informed decisions.
- [Interest Rates](/concepts/financial/interest-rates): **Interest rates** are the heartbeat of Euler's lending protocol, driving the flow of capital between lenders and borrowers. Every time a transaction occurs in a block, borrowers pay interest on their outstanding loans, with this interest being compounded every second. The specific rate at any given moment is determined by an Interest Rate Model (IRM), which is unique to each credit vault in the protocol.
- [Rewards](/concepts/financial/rewards): Euler offers a sophisticated rewards system that incentivizes participation in its vaults through both on-chain and off-chain mechanisms. These rewards are designed to provide additional value to participants, all while maintaining the protocol's efficiency and security.
- [Strategy Profitability](/concepts/financial/strategy-profitability): Understanding the true profitability of your Euler strategies requires careful consideration of various factors beyond the surface-level returns. While the Euler interface provides clear visibility into your positions, it's crucial to understand how different costs and market dynamics can impact your actual profits.
- [Ethereum Vault Connector](/concepts/core/evc): The **Ethereum Vault Connector (EVC)** is a foundational layer designed to facilitate core lending market functionality. It serves as a base building block for various protocols, providing a robust and flexible framework for developers to build upon. The EVC primarily mediates between vaults - contracts that implement the [ERC-4626](https://eips.ethereum.org/EIPS/eip-4626) interface and contain additional logic for interfacing with other vaults.
- [Markets](/concepts/core/markets): A market on Euler is a marketplace where borrowers obtain loans and lenders provide capital (in the form of crypto assets) in exchange for interest. On Euler, builders can create custom markets by deploying vaults with the **Euler Vault Kit (EVK)** and linking them using the **Ethereum Vault Connector (EVC)**.
- [Price Oracles](/concepts/core/price-oracles): Price oracles are fundamental to Euler's lending protocol, providing the real-time price data needed to ensure borrowers remain over-collateralized and the system maintains its stability. These oracles are crucial for determining collateralization levels, triggering liquidations, and maintaining overall system health. Euler's oracle-agnostic and modular design allows seamless integration with any type of external price feed, giving vault creators and risk curators maximum flexibility in asset and risk management.
- [Vaults](/concepts/core/vaults): Vaults are the fundamental building blocks of the Euler protocol, serving as the primitive unit for all lending and borrowing activities. In Euler, there are two main types of vaults: **Euler Vault Kit (EVK)** vaults and **Euler Earn** vaults, each serving distinct purposes while sharing common underlying principles.
- [EulerSwap](/concepts/advanced/euler-swap): EulerSwap is a new decentralized exchange that integrates directly with Euler's lending infrastructure and leverages Uniswap v4's hook architecture. By combining the best of modular DeFi powerhouses, EulerSwap unlocks next-generation capital efficiency for market makers, liquidity providers, and traders.
- [Fee Flow](/concepts/advanced/fee-flow): **Fee Flow** is a powerful open-source module that enables the auctioning of protocol fees for EUL tokens (or other). These auctions convert protocol-generated fees (e.g., in USDC, DAI, or other assets in form of the vault shares) into EUL, which flows back to the Euler DAO treasury. The DAO can then decide, via governance, how to use these funds (e.g., burn, distribute, or allocate for growth).
- [Hooks](/concepts/advanced/hooks): **Hooks** are a powerful feature in Euler that allows vault governors to customize and control vault operations. By implementing a hook configuration, governors can specify a hook target (a smart contract) and define which vault operations should trigger the hook. This system provides a flexible way to add custom logic and restrictions to vault operations without modifying the core vault code.
- [Operators](/concepts/advanced/operators): **Operators** represent a powerful generalization of the traditional token approval system in Euler, enabling users to delegate permissions to external contracts that can act on their behalf. This feature unlocks a wide range of advanced functionality, particularly for users who prefer to interact with the protocol through external interfaces or automated systems.
- [Reward Streams](/concepts/advanced/reward-streams): **Reward Streams** is an innovative open-source module that enables projects to seamlessly stream rewards to users of new markets in a permissionless manner. This module implements the billion-dollar algorithm, allowing for the simultaneous distribution of multiple reward tokens.
- [Sub-accounts](/concepts/advanced/sub-accounts): **Sub-accounts** are a powerful feature in Euler that allows users to create multiple isolated positions within a single wallet address. This innovative approach to account management provides users with the flexibility to manage different strategies and risk profiles while maintaining the convenience of using a single wallet.
- [Swaps](/concepts/advanced/swaps): **Swaps** are a cornerstone of advanced position management in Euler. They enable users to move seamlessly between assets, manage leverage, rebalance portfolios, and automate complex strategies—all within the protocol's modular, composable architecture. Understanding swaps is key to unlocking the full power of Euler's advanced features, especially when combined with concepts like sub-accounts, hooks, and operators.
- [Unit of Account](/concepts/advanced/unit-of-account): In the world of decentralized finance, where countless ERC-20 tokens exist, there's a fundamental need for a standardized way to express and compare asset values. This is where the concept of a unit of account comes into play. It serves as a common reference currency that allows the Euler protocol to make sense of the complex web of asset relationships, enabling everything from price comparisons to collateral valuations.
- [Fee Flow](/EUL/fee-flow): Fees collected from Euler vaults are periodically auctioned through Fee Flow auctions. These auctions use EUL as the bidding currency, ensuring that protocol-generated fees are consistently converted into EUL. The accumulated EUL currently returns to the Euler DAO treasury, but the DAO could choose to burn it, distribute it as incentives for EUL stakers or protocol users, or allocate it in any other way it deems appropriate through governance proposals.
- [Multichain](/EUL/multichain): Euler uses LayerZero's Omnichain Fungible Token (OFT) standard for bridging EUL tokens across networks. The addresses of multichain EUL are listed [here](./addresses).
- [Overview](/EUL/overview): **EUL** is an ERC20 token that acts as the native governance token of the Euler protocol. EUL tokens are used in [Fee Flow](./fee-flow) auctions, serve as rewards on the platform, and represent voting power to effect change over the Euler protocol code or the Euler DAO treasury. EUL can be freely transferred between multiple networks. Find the official addresses [here](./addresses).
- [Reward EUL](/EUL/reward-eul): Reward EUL (rEUL) is a locked form of EUL designed to incentivize early adopters of the v2 version of the protocol. Users of Euler receive rEUL rewards by participating in supported markets, with both supply and borrow activities eligible for rewards. The rEUL token converts 1:1 into EUL over six months, following a non-linear unlock schedule:
- [Addresses](/EUL/addresses): Always verify addresses using official sources. Only use addresses listed here or in the [**Euler Interfaces GitHub Repository**](https://github.com/euler-xyz/euler-interfaces/tree/master/addresses) to avoid scams or phishing attempts.