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Before deploying an Ethereum or other EVM smart contract, review what it is meant to do, what must always remain true, who can control it, how it handles hostile inputs and external calls, and whether its tests, deployment settings, and operating procedures match the design. Use the checklist below to organize that review; neither automated tools nor an independent audit can guarantee a contract is safe.
1. Define the scope and security assumptions
Start with a short, reviewable description of the contract’s purpose and the conditions under which it should work. A reviewer cannot assess whether behavior is safe without knowing what behavior was intended.
- Identify the assets, permissions, and user actions at risk if the contract behaves incorrectly.
- Document who is trusted, what each trusted party can do, and which assumptions depend on external contracts, tokens, oracles, or other systems.
- Write down critical security properties and invariants: conditions that must remain true across every relevant state change.
- Record the target chain, language, compiler, architecture, and threat model. A checklist for Ethereum or EVM contracts should be adapted to the actual chain and implementation.
Ethereum.org’s Smart contract security checklist recommends documenting security properties and testing them. Give reviewers the specification, architecture, and dependency information they need to check those properties against the implementation.
2. Trace permissions and privileged actions
Build a clear map from each sensitive action to the account or role that can perform it. Include every path that can change contract behavior or control funds, not just functions named “admin.”
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- Review ownership, role assignments, role-granting and role-revoking functions, and any transfer of ownership.
- List who can mint, withdraw, change configuration, pause or resume activity, upgrade the implementation, or trigger an emergency action.
- Check authorization on inherited functions and on every state-changing path that affects privileged settings or assets.
- Test both sides of each boundary: authorized calls should succeed under the intended conditions, while unauthorized calls should revert.
- Check role changes and emergency paths, including whether they can leave the system without a necessary administrator or unable to recover.
A multisignature arrangement can require several parties to approve sensitive actions, but it does not remove the need for correct role design and secure key handling. Document who holds the relevant keys and what approvals are required.
3. Review state changes, inputs, and external interactions
For each public or external function, follow how inputs change state and what happens if calls occur in an unexpected order. Review ordinary use as well as failure paths and adversarial conditions.
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- Check boundary values, invalid inputs, repeated calls, and transitions between important states.
- Verify that the documented invariants still hold after successful calls, failed calls, and sequences of calls.
- Inspect external calls and integrations, including token and DeFi interactions, for assumptions about how another contract will behave.
- Assess reentrancy risk wherever control passes to an external contract. Ethereum.org describes checks-effects-interactions as one way to reduce this risk: account for the contract’s state changes before making the external interaction.
- Consider front-running and cryptographic operations where they matter to the design. These risks and assumptions may need focused human review rather than reliance on an automated finding list.
Be especially careful where a function’s safety depends on call order, an external contract’s behavior, or a value that can change between transactions. Make those assumptions explicit and test them where practical.
4. Test the specification and interpret analysis results
Use more than a happy-path unit test suite. Ethereum.org says testing smart contracts before deploying to Mainnet is a minimum requirement for security. Choose additional methods according to the contract’s risk and how precisely its expected behavior can be specified.
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- Run unit tests for normal use, boundary values, invalid inputs, authorization failures, and important state transitions.
- Add property-based or stateful tests for invariants that must hold across many inputs or sequences of actions.
- Consider fuzzing and formal verification when the risk and quality of the specification justify them.
- Run static analysis and investigate findings in context; a clean report is not proof that no defect exists.
- Use dynamic analysis where appropriate, and test integrations and deployment scripts in a suitable test environment.
- Review compiler warnings and output rather than treating a successful build as a security result.
Ethereum.org’s Smart contract security checklist, dated March 3, 2026, describes Slither as having more than 40 built-in detectors and Crytic as covering “50 issues that Slither does not.” These are descriptions of tool coverage in that checklist, not a guarantee that running either tool will identify every defect in a particular contract.
5. Check dependencies, standards, and the compiled source
Review what the contract inherits from and relies on, as well as what was actually compiled. A familiar interface or library does not remove the need to check how the project uses it.
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- Prefer well-tested libraries and manage dependencies rather than copying code without a clear reason.
- Check claimed standards conformance against the implementation and the project’s actual integration requirements.
- Inspect inherited behavior and storage-variable authorization where relevant to the architecture.
- Confirm the compiler configuration and inspect warnings and generated output for the build being prepared for deployment.
- Ensure reviewers can identify the dependencies and versions used in the reviewed source.
6. Confirm deployment and source verification
Before launch, compare the intended release with the artifact and configuration that will be deployed. After deployment, verify the published source against the on-chain bytecode so others can inspect the code associated with the deployed address.
- Confirm the compiled artifact, compiler configuration, deployment target, and constructor or initialization parameters.
- Review the deployment script and the values it supplies; check that they match the approved configuration.
- After deployment, check the deployed address and runtime code, and verify the source using the process supported by the target chain or verification service.
- Compare the deployed configuration and address with the release record before directing users or integrations to the contract.
Ethereum.org’s source-code verification guidance explains that verification checks whether published source corresponds to deployed bytecode. Verification improves inspectability; it does not establish that the code is secure.
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7. Plan for upgrades, incidents, and key security
Decide how defects and operational problems will be handled before they occur. The right procedure depends on whether the deployed system can change and on which parties hold authority.
If the system is upgradeable
- Review who can authorize and execute an upgrade, and test those permission boundaries.
- Document the proxy or migration assumptions and the steps for proposing, reviewing, and executing a change.
- Plan how migration effects and the resulting system state will be checked.
If the deployed code is immutable
Understand that deployed code cannot simply be patched. Decide how the project would respond to a defect or unsafe behavior, including what users and integrators should be told and what actions remain available under the design.
For either design
- Secure privileged wallets and keys, and make the approval process for sensitive actions clear.
- Define what will be monitored, who receives alerts, and how relevant people will be contacted.
- Write an incident-response procedure that identifies decision-makers and the actions the system permits in an emergency.
8. Make independent review actionable
Give reviewers the contract scope, architecture documentation, intended properties, threat assumptions, and relevant dependencies. State which components and integrations are in scope so that review coverage is clear.
- Ask for findings to be specific enough to reproduce and understand their impact.
- Track each finding through a decision and, where changes are made, retest the remediation.
- Keep the reviewed code and deployed release aligned; material changes after review may require further review.
- Assess an audit’s scope, methods, relevant chain and language experience, reporting, and remediation support rather than relying on the word “audited.”
Ethereum.org cautions against treating audits as a “silver bullet.” An audit can uncover defects missed by other review, but it cannot guarantee that none remain. OpenZeppelin reports more than 700 Critical and High vulnerabilities uncovered, more than 1 million lines of code reviewed, and more than $110 billion in total value locked secured; these are OpenZeppelin-reported featured-audit figures collected as of April 2025, not industry-wide totals or a measure of the safety of any particular contract.
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