Hacken’s top auditor has developed a comprehensive, open-source testing harness for Uniswap v4 hooks, enabling automated validation of their security, correctness, and behavior.
Uniswap v4 introduces a powerful new primitive: hooks. They enable developers to customize pool behavior at key execution points, unlocking dynamic fees, custom AMM logic, on-chain strategies, and more.
But this flexibility also brings new risks. Misaligned permission flags, incorrect delta handling, unsafe async behavior, or faulty accounting can break pool execution or expose users to loss. Without thorough, systematic testing, some code issues in Uniswap v4 are impossible to detect.
To support developers and improve reliability across the ecosystem, Hacken is open-sourcing the Uniswap v4 Hook Testing Framework—a Foundry-based test harness that validates both the functional correctness and the security properties of hook implementations.
Developed by Olesia Bilenka, Blockchain Security Engineer at Hacken, the framework provides automated checks for the most likely problems:
- incorrect or mismatched permission flags
- unsafe delta manipulation
- missing or weak access control
- invalid selectors and return types
- improper pool attachment logic
- settlement inconsistencies and revert paths
The goal is to give teams a reliable, repeatable way to verify hook behavior throughout the entire development lifecycle—during implementation, CI/CD, pre-deployment testing, and post-audit maintenance.
Key Features of Hacken’s Uniswap v4 Hook Automated Testing
Capability Detection
- Parses hook address flags to determine implemented callbacks
- Conditionally executes tests based on Hooks.Permissions bitmap
- Validates permission consistency between address flags and getHookPermissions()
Security Validation
- Access control: Verifies onlyPoolManager modifier on all entry points
- Delta integrity: Validates BeforeSwapDelta handling and settlement accounting
- State isolation: Checks for proper pool key validation and exclusivity patterns
- Return value correctness: Ensures proper selector returns for all callbacks
Functional Coverage
- Core operations: Swap (both directions), liquidity modification, donations
- Delta mechanics: Tests beforeSwapReturnDelta, afterAddLiquidityReturnDelta, etc.
- Edge cases: Sequential operations, boundary values, revert scenarios
- Integration: Full PoolManager interaction flows with proper router usage
Extensibility
- Fuzz testing support via Foundry's property-based testing
- Configurable strictness via environment variables
- Fork-compatible for testing deployed hooks
- Modular test suites for custom extension
Key Use Cases
Development & CI/CD
- Integration testing during hook development
- Regression detection in continuous integration pipelines
- Pre-deployment validation of security properties
Security Audits
- Automated verification of common vulnerability patterns
- Access control and authorization validation
- Delta manipulation and accounting correctness checks
Protocol Integration
- Third-party hook verification before allowlisting
- Compliance validation against Uniswap v4 hook standards
- Behavior analysis under various market conditions
Get Started With the Uniswap v4 Hook Testing Framework
For a demo, full installation steps, example tests, architecture details, and troubleshooting, the complete documentation is available in the GitHub repository at https://github.com/hknio/uni-v4-hooks-checker
The repo includes a Quick Start guide for installing Foundry, building the framework, running example hooks, and configuring your own tests. It also covers testing on mainnet forks or Anvil, writing custom test contracts, using environment variables, enabling fuzzing, and resolving setup issues—everything needed to integrate the framework into your local workflow or CI/CD pipeline.
Take the Next Step Toward Secure Uniswap v4 Development
With Uniswap v4 rapidly gaining adoption, the need for reliable, security-focused testing tools has never been greater. This open-source framework makes safe hook development more accessible, unifies testing practices, and gives developers, auditors, and protocols a dependable way to spot issues early and validate third-party hooks before they go live.
If your project relies on Uniswap v4 hooks (e.g., custom AMMs, liquidity automation, reward systems, or other DeFi logic) security is critical. Automated tools assist development, but expert review is essential for catching subtle, high-impact vulnerabilities. Hacken delivers industry-leading Smart Contract Audits with deep expertise in Uniswap v4 and complex protocol mechanics. Request a free consultation today and secure your integration before going live.
Learn More About Uniswap Hooks & Security
A collection of deep-dive research articles produced by Hacken’s top smart contract auditors, based on real auditing practice across Uniswap v2–v4 and some of the most complex DeFi systems in production.
🔗 Uniswap v4 & Transient Storage Security
