Overview

Integrate directly with Gearbox contracts from your Solidity code. This guide covers on-chain integration patterns for smart contract developers.

Prerequisites

Solidity 0.8.x experience
Familiarity with interface-based contract interaction
Understanding of ERC-20 and common DeFi patterns

What You'll Learn

Topic	Description
Credit Accounts	Contract discovery, CreditFacade, CreditManager interactions
Multicall Encoding	Build and execute multicalls in Solidity
Pool Operations	Deposit, withdraw, and read pool state

Guide Structure

Credit Accounts - Contract discovery, ICreditFacadeV3, ICreditManagerV3 interfaces
Multicalls - MultiCall struct encoding, adapter calls
Pool Operations - IPoolV3 deposit/withdraw, ERC-4626 functions

Note: Contract discovery patterns (AddressProvider, ContractsRegister) are covered in the Credit Accounts guide.

Key Interfaces

Solidity

// Core interfaces you'll use
import {IAddressProviderV3} from "@gearbox-protocol/core-v3/contracts/interfaces/IAddressProviderV3.sol";
import {ICreditFacadeV3} from "@gearbox-protocol/core-v3/contracts/interfaces/ICreditFacadeV3.sol";
import {ICreditManagerV3} from "@gearbox-protocol/core-v3/contracts/interfaces/ICreditManagerV3.sol";
import {IPoolV3} from "@gearbox-protocol/core-v3/contracts/interfaces/IPoolV3.sol";

When to Use Solidity Integration

Use Case	Recommended
On-chain protocol integration	Yes
Building adapters	Yes
Composable strategies	Yes
Backend services	No (use SDK Guide)
Frontend applications	No (use SDK Guide)

For TypeScript/JavaScript applications, see the SDK Guide.

Architecture Understanding

For conceptual background on how Gearbox works:

Credit Suite Architecture - How Credit Managers, Facades, and Configurators work together
Pool Architecture - Lending pools and ERC-4626 compliance
Multicall System - How multicalls execute and validate

Detailed Guides

Multicall Operations

Complete reference for each multicall operation with Solidity examples:

Operation	Description
Adding Collateral	Transfer tokens to credit account
Debt Management	Borrow and repay
Updating Quotas	Manage collateral quotas
Withdrawing Collateral	Remove tokens from account
Controlling Slippage	Protect against price movement
Making External Calls	Interact with DeFi protocols via adapters
Enabling/Disabling Tokens	Manage active collateral
Updating Price Feeds	On-demand oracle updates (Pyth, Redstone)
Collateral Check Params	Optimize health checks with hints
Revoke Allowances	Security cleanup

See Multicalls Overview for the diff pattern and complete encoding examples.

Use Case Guides

Integration-specific guides for common development scenarios:

Building	Guide	Focus
New DeFi Adapter	Adapter Development	AbstractAdapter, security patterns, diff functions
Strategy Contract	Protocol Integration	Multicall building, access control, automation
Core Extensions	Core Extension	Extending core contracts, advanced customizations
Liquidation Contract	Liquidation Bots	On-chain liquidation, flash loans, keeper integration