Code Audits
Smart Contract Audit
Your first line of defense against exploits. We analyze your smart contracts for vulnerabilities, inefficiencies, and potential attack vectors, ensuring your code is secure, optimized, and built to last.
100+
audits
completed
$8.2B
in client assets protected
$183.2B
in transacted value secured
300+
crit / high issues found
Consolidated clients
A smart contract audit firm with
3+ years of expertise
Our team of smart contract security specialists combines automated analysis with in-depth manual reviews, threat modeling, and Web3 security best practices. Whether you are building DeFi applications, blockchain infrastructure, or on-chain games, we ensure your smart contract audit delivers bug-proof, efficient, and mainnet-ready code.
What is a Smart Contract Audit?
A smart contract audit is a specialized code review designed to identify vulnerabilities, optimize performance, and ensure your protocol’s code behaves exactly as intended. This includes reviewing contract architecture, upgradeable proxy patterns, state management, role-based access controls, and transaction flow to ensure the system operates securely under real-world conditions. For teams with broader needs, we also perform Dapp Audits and Opsec Audits as part of a complete audit scope.
Why does a Smart Contract Audit Matter?
The majority of DeFi exploits happen at the smart contract level. Even small logic errors can be exploited to drain funds, disrupt operations, or permanently damage your brand’s reputation. A smart contract audit not only reduces this risk but also increases investor and user trust, improves code efficiency, and helps align your protocol with industry security standards. In Web3, security is a growth driver, and a well-audited protocol is far more likely to attract long-term users, partnerships, and liquidity.
Our Approach to Smart Contract Auditing
Choosing the right smart contract auditor is an important decision, it's not just about getting a report, it's about trusting someone to protect everything you've built. Every smart contract audit from Three Sigma delivers more than just a PDF. As a smart contract audit firm, we strengthen your codebase against known and emerging threats, improve gas efficiency, align with industry best practices, and give your team crystal-clear guidance they can act on immediately.
We tailor each smart contract audit to your protocol’s architecture, ecosystem, and use case.
Whether your project runs on:
We account for unique language risks, dependency interactions, and upgradeability concerns. Our process is designed not just to identify problems but to provide practical, high-impact recommendations that make your contracts more secure, efficient, and resilient.
Common Smart Contract Vulnerabilities Found
Access Control Bugs
They usually occur when privileged functions lack proper restrictions, or roles are misconfigured, allowing unintended actors to call upgrade, withdraw, or ownership functions.
Oracle Manipulation
Happens when price feeds are derived directly from DEX/AMM pools without safeguards, making them vulnerable to flash-loan-driven price distortions or thin-liquidity manipulation. Also seen in GameFi protocols, where unstable pricing can distort rewards.
Logic Errors
Show up when code behaves correctly, but not as intended, often due to flawed assumptions, missing edge case handling, or misunderstanding protocol-level incentives. Critical in Solana and Rust-based protocols, where custom logic often escapes standard tool coverage.
Input Validation Failures
Occur when contracts accept parameters without checking them, zero addresses, oversized values, unsupported tokens, or inputs that trigger downstream bugs like overflows or failed transfers.
Reentrancy
Emerges when external calls are made before state changes, allowing attackers to re-enter the contract mid-execution, especially in multi-call or callback-heavy designs.
DoS via Gas
Typically happens when unbounded loops, mappings, or calculations scale with user data, leading to failed transactions once operations hit gas/compute limits.
Private Key Risk
Rooted in human error: compromised dev wallets, poor key storage, or poorly configured multisigs/shared credentials used to deploy contracts or manage upgrades, exploits that technology alone can not prevent.
DeFi smart contract vulnerabilities drained over $730 million in 2024, with more than half targeting already audited code. Common weaknesses include improper access control, flawed logic handling, missing input validation, and reliance on insecure external oracles. Inefficient gas usage can create denial-of-service conditions, while reentrancy bugs and unchecked upgrade mechanisms may open paths to total protocol compromise, making early security prioritization essential for long-term resilience.
Our Smart Contract Audit Process
Scoping and Planning
We define the full smart contract audit scope, listing contract modules, dependencies, and critical functions to review.
Architecture Review
We evaluate the protocol’s architecture, focusing on how contracts interact, potential attack surfaces, and systemic security risks.
Code Review
We perform a smart contract security review line-by-line to detect vulnerabilities, inefficiencies, and deviations from best practices.
Testing
Static analysis, property-based fuzzing and invariants, and mainnet-fork simulations; we build PoCs to reproduce issues and measure real-world impact.
Reporting & Recommendations
We provide an audit report and step-by-step remediation guidance.
Verification
We assist your team with fixes to confirm all issues have been resolved before mainnet deployment.
Hear from our Clients
Deliverables You Can Expect
Check out our previous Case Studies and their reports, outlining all identified vulnerabilities, their severity, and actionable remediation steps.
Post-audit support is included
to help your team implement fixes and validate their effectiveness.
Our smart contract audit deliverables are not just a checkmark on your roadmap, they provide technical clarity, actionable security improvements, and documentation you can present to investors, partners, or compliance teams.
What You Gain
from a Three Sigma Audit
Our smart contract security audit is more than a checkmark, it’s an investment in your project’s success.
Prevent costly exploits before they impact your users.
Increase trust with investors, partners and the Web3 community.
Accelerate compliance with evolving blockchain security standards.
Protect brand reputation in an industry where trust is currency.
Industries We Secure
Our audits have helped secure decentralized applications across multiple verticals.
DeFi
Lending platforms, DEXs, and staking protocols.
NFT & Collectibles
Marketplaces, launchpads, and minting platforms.
Gaming & Metaverse
Play-to-earn games, asset trading hubs, and immersive experiences.
Cross-Chain Infrastructure
Bridges, oracles, and interoperability layers.
Frequent answers and questions
Check out the Smart Contract Audit F.A.Q.
Why is a smart contract audit necessary?
A smart contract audit identifies vulnerabilities before deployment, preventing exploits, financial losses, and protocol failures.
How long does a smart contract audit take?
The duration depends on the project's scope and complexity, but audits typically take 1-6 weeks.
What are the most common vulnerabilities found in smart contracts?
Reentrancy, integer overflows, logic errors, access control flaws, and gas inefficiencies.
How much does a smart contract audit cost?
Costs vary based on contract complexity but generally range from $10K to $75K+.
What happens if issues are found during the audit?
We provide a detailed explanation in real time of the finding with the corresponding recommended fix.