Top 15 Smart Contract Auditing Firms for Blockchain Security in 2025

Choosing the right smart contract auditing company can be a bit tricky.

There are plenty of great options out there, but picking the one that fits your needs requires some research.

We've done the heavy lifting for you by reviewing and analyzing a range of auditing services to help you find the best one to secure your protocol and codebases.

In this article, we’ll look at the top 10 smart contract auditing companies and what sets them apart.

But before we dive in, let’s quickly go over what smart contract auditing is and why it’s so important for your project.

Why are Smart Contract Audits Necessary?

Smart contracts are efficient and reliable, but they handle valuable digital assets, making strong security a must.

The value stolen from DeFi protocols dropped in 2023, but 2024 saw a troubling increase in stolen funds and hacks.

Now you know why it is necessary.

What is a Smart Contract Audit?

A smart contract audit is a detailed security review of your contract’s code to find and fix vulnerabilities.

Auditors go through the code manually and with automated tests to make sure it follows best practices and is safe from potential exploits.

There are different types of audits, including competitive audits, where multiple researchers compete to find vulnerabilities, and private audits, where top experts work closely with your team.

What Do Smart Contract Auditing Companies Do?

Smart contract auditing companies are specialists in analyzing and stress-testing code to find vulnerabilities, bugs, or unexpected behaviors.

They offer guidance to help improve the security of your contract.

Whether you're dealing with pre-deployment contracts, deployed contracts, or those in any audit stage, these experts are essential.

How to Choose the Right Auditing Service

Picking the right auditing service for your project isn’t easy.

You need to consider factors like experience, reputation, transparency, technical expertise, and cost.

A good audit company will have a proven track record with prominent protocols and be transparent about their process.

With that in mind, let’s look at the top 10 smart contract auditing companies for this year.

QuillAudits is a leading blockchain security firm specializing in smart contract audits and comprehensive Web3 security solutions. Established in 2018, QuillAudits has successfully served over 1,000 clients, ensuring the security of their blockchain projects.

Smart Contract Audit Services

QuillAudits offers specialized security assessments tailored for Web3 projects, including:

• Smart Contract Audits: In-depth manual and automated reviews to detect vulnerabilities.
• Penetration Testing: Simulated cyberattacks to identify and address security weaknesses.
• Security Advisory Services: Consulting on protocol design, governance mechanisms, and threat modeling.

Expertise

QuillAudits specializes in smart contract security, penetration testing, forked protocol audits, V2 audits, dapp audits, wallet audits, Eigenlayer AVS audits and a lot more. Their team comprises seasoned blockchain developers and security analysts, all experts in their respective fields, having over 7 years of experience in smart contract auditing. They support over 20 chains - EVM, non-EVM, & alt-VMs as well. QuillAudits also offer upto 10k USD in audit credits to eligible partners via their WAGSI program.

Selected Clients

Starkware, Taiko, Zetachain, Metis, Astra DAO, Zoth

Zellic is a leading blockchain security firm specializing in smart contract audits and cryptographic research. Founded by security experts with backgrounds in top-tier cybersecurity competitions, Zellic provides high-assurance security solutions to the most complex Web3 protocols.

Smart contract audit services

Zellic offers specialized security assessments tailored for Web3 projects, including:

• Smart contract audits: Deep manual and automated reviews to detect vulnerabilities.
• Cryptographic audits: Evaluating zero-knowledge proofs (ZKPs), multi-party computation (MPC), and other advanced cryptographic systems.
• Security advisory services: Consulting on protocol design, governance mechanisms, and threat modeling.

Expertise

Zellic specializes in smart contract security, cryptographic verification, and blockchain protocol analysis. It works with EVM-compatible chains, Cosmos, Solana, and other next-generation blockchain architectures.

Selected Clients

Aptos, StarkWare, LayerZero, Scroll, Wormhole, Sei, Monad, and more.

OpenZeppelin, a cybersecurity pioneer, has been securing blockchain assets since 2015, protecting over $50 billion in the most prominent blockchain organizations.

Smart Contract Audit Services:

• Smart Contract Audits: Comprehensive reviews of system architecture and code to detect and resolve vulnerabilities.
• Ethernaut: An interactive game that teaches developers smart contract security by letting them exploit vulnerabilities.
• Defender: A platform designed to deploy, monitor, and automate smart contract operations securely.

Expertise:

OpenZeppelin excels in secure blockchain development, offering trusted Solidity and Cairo libraries, smart contract audits, and zero-knowledge-proof services.

Selected Clients:

Bancor, Celo, 1inch, The Graph, Origin, Cross Chain Swaps, and more.

Nethermind Security is a specialized arm of Nethermind, a key contributor to Ethereum and other blockchain ecosystems. It focuses on providing top-tier security research and smart contract auditing services.

Smart contract audit services

Nethermind Security offers:

• Smart contract audits: Comprehensive reviews of Solidity and Cairo-based contracts, leveraging in-depth knowledge of Ethereum and Starknet.
• Formal verification: Mathematical modeling to ensure correctness and safety.
• Security research & consulting: Deep-dive research into blockchain vulnerabilities and security best practices.

Expertise

With strong ties to Ethereum core development, Nethermind Security is deeply embedded in blockchain infrastructure, specializing in Ethereum, Starknet, and other L2 scaling solutions.

Selected Clients

StarkWare, Scroll, Aave, MakerDAO, Gnosis, Mantle, and more.

Since 2012, TrailOfBits has addressed complex security challenges by designing new technologies and researching cutting-edge products to ensure their security.

Services:

• Software Assurance, Security Engineering, and Research & Development.
• Echidna: A property-based fuzzer for Ethereum smart contracts.
• Manticore: A symbolic execution tool for analyzing binaries and smart contracts.
• Slither: A static analysis tool for Solidity.

Expertise:

Specializing in reverse engineering, cryptography, malware analysis, and software exploitation.

Selected Clients:

Acala, Balancer, Frax, Liquity, MakerDao, Parity, Yearn, and more.

Cyfrin has earned the trust of leading protocols like ZKsync, Chainlink, Wormhole, Securitize, Lido, Starknet, and Ethena. With the expertise of world-class security researchers and a global community of thousands of top auditors, Cyfrin is on a mission to reduce DeFi theft by 1% annually.

Smart Contract Audit Services:

• Private Audits: Expert security researchers meticulously review every line of code to ensure it is secure and reliable.
• CodeHawks: A competitive, gamified auditing platform where auditors from around the world battle to find vulnerabilities and win prizes.
• Solodit: A platform that aggregates thousands of security vulnerabilities, bounties, and research to improve dApp and smart contract security.
• Aderyn: An open-source Rust-based tool for static analysis, designed to identify vulnerabilities in Solidity contracts by analyzing their Abstract Syntax Trees (AST).
• Cyfrin Updraft: An educational platform with blockchain development and Web3 security courses, boasting a community of over 200,000 students.

Expertise:

Cyfrin specializes in Solidity and Vyper smart contract audits, utilizing tools like Foundry, Hardhat, Brownie, Apeworx, and Truffle to ensure comprehensive assessments.

Selected Clients:

ZKsync, Chainlink, Wormhole, Securitize, Lido, Starknet, Ethena, Uniswap, and many more.

Spearbit is a decentralized network of security experts offering Web3 security consulting services. They bridge the gap between independent security researchers and Web3 projects that require their expertise.

Auditors must undergo a rigorous screening process to become part of Spearbit and receive the appropriate designation.

Smart Contract Audit Services

Spearbit strengthens the Web3 security ecosystem by offering security reviews and consulting services. Their platform also supports independent auditors looking for flexibility and provides educational content for security enthusiasts.

Expertise

Spearbit's technology stack includes protocol design, smart contracts, and Solidity compilers. They employ advanced security assessment tools such as Foundry for testing, fuzzing campaigns, and formal verification.

Selected Clients

Redacted, Primitive, NFTX, BadgerDAO, Morpho, Llame, etc.

Veridise is a security firm that combines manual audits with formal verification techniques to provide high-assurance smart contract security. The team consists of experts in blockchain security, programming languages, and automated verification.

Smart contract audit services

Veridise offers:

• Smart contract audits: Manual and automated security assessments.
• Formal verification: Using mathematical proofs to validate the correctness of smart contracts.
• Static and dynamic analysis: Advanced techniques to detect potential vulnerabilities before deployment.

Expertise

Veridise is known for its deep expertise in formal verification, static analysis, and vulnerability detection. The firm supports EVM-based and non-EVM smart contract platforms.

Selected Clients

Ethereum Foundation, Chainlink, Near Protocol, Compound, and more.

Consensys Diligence has been helping over 100 teams launch secure decentralized apps (dApps) with confidence.

Smart Contract Audit Services:

• In-depth Audits: Manual code reviews and tools like Mythril and Scribble.
• Threat Modeling: Analyzing and visualizing a project's attack surface.
• Fuzzing: Identifying vulnerabilities before deployment through automated fuzz testing.
• Security Tools: A suite of tools, including Surya, Karl, and Theo, for analyzing and visualizing smart contracts.

Expertise:

Specializing in auditing Ethereum and EVM-compatible smart contracts, combining manual reviews with automated testing.

Selected Clients:

Lybra Finance, Wallet Guard, Socket, Rocket Pool Atlas, Forta, and more.

Hacken is a blockchain security firm offering a wide range of security services, including smart contract audits, bug bounties, and real-time monitoring. With a strong emphasis on ethical hacking, Hacken provides security solutions for DeFi, NFTs, and enterprise blockchain applications.

Smart contract audit services

Hacken provides:

• Smart contract audits: In-depth code analysis with automated and manual security reviews.
• Penetration testing: Simulated attacks to identify vulnerabilities in blockchain infrastructure.
• Bug bounty programs: Running security programs with white-hat hackers to discover potential risks.
• On-chain security monitoring: Continuous threat detection for smart contracts and DeFi protocols.

Expertise

Hacken specializes in Web3 cybersecurity, DeFi security, penetration testing, and blockchain forensics. It also runs HackenProof, a bug bounty platform that connects security researchers with blockchain projects.

Selected Clients

1inch, Polygon, Avalanche, DAO Maker, Tether, and more.

Sigma Prime is a blockchain security leader, advancing decentralized technologies through secure solutions and open-source development.

Smart Contract Audit Services:

• Smart Contract Audits: Thorough reviews of Ethereum contracts.
• Protocol Design Reviews: Ensuring secure blockchain protocol architecture.
• Formal Verification: Using mathematical verification to ensure contract correctness.
• Fuzz Testing and Consensus Security Assessments.

Expertise:

Specialized in Ethereum and related technologies, including Lighthouse, a secure Ethereum 2.0 consensus client.

Selected Clients:

AlphaWallet, Filecoin, Gearbox, Infinigold, Synthetix, Protocol Labs, and more.

CodeHawks is a competitive auditing platform powered by Cyfrin, designed to help secure smart contracts through a global community of auditors.

Smart Contract Audit Services:

• Competitive Audits: A community of auditors competes to identify vulnerabilities.
• First Flights: Beginner-friendly challenges to gain real-world auditing experience.

Expertise:

CodeHawks is a versatile platform, inviting auditors skilled in multiple languages and blockchain networks to participate in audits.

Selected Clients:

ZKsync, Chainlink, Starknet, Sabiler, MorpheusAI, LinkPool, Vyper, and many more.

Code4rena organizes competitive audits with a community of auditors known as "Wardens" to identify vulnerabilities in blockchain projects. Despite being acquired by Zellic in 2024, Code4rena operates independently.

Smart Contract Audit Services:

• Open Audits: Public audits open to everyone.
• Private Audits: Exclusive audits for certified contributors.
• Invitational Audits: Top auditors collaborate on specific projects.
• Bot Races: Automatic detection of vulnerabilities through bots.

Expertise:

Specializing in DeFi protocols, Code4rena leverages the collective knowledge of its auditor community.

Selected Clients:

Ronin, Basin, Canto, Thorchain, Optimism, ZKSync, and more.

ChainSecurity specializes in auditing smart contracts and enhancing blockchain security for DeFi protocols, Web3 projects, and central banks.

Smart Contract Audit Services:

• Code Reviews: In-depth smart contract audits to identify vulnerabilities.
• Security Assessments: Evaluating blockchain clients and protocols for enhanced network integrity.

Expertise:

ChainSecurity is known for auditing complex codebases across EVM-compatible chains and NEAR projects, focusing on rigorous quality assurance.

Selected Clients:

Tron, Circle, MakerDAO, Lido, Uniswap, Yearn.Finance, and more.

Dedaub provides end-to-end security solutions, having completed over 100 full-protocol audits and preventing $1.5 billion in losses through white-hat interventions.

Smart Contract Audit Services:

• Comprehensive Audits: Thorough code analysis to identify vulnerabilities.
• Web3 Protocol Design Advisory: Expert guidance on secure protocol design.
• WatchDog: Real-time monitoring platform to prevent hacks.

Expertise:

Dedaub’s team includes PhD-level blockchain experts and cryptographers who have authored numerous impactful papers.

Selected Clients:

Lido, Yearn.Finance, Liquidity, GMX, Eigenlayer, Oasis Network, and more.

Why Does Security Matter

The blockchain industry thrives on trust, and smart contract security forms the bedrock of that trust.

Selecting the right security partner goes beyond just ticking a box — it’s about ensuring the safety and resilience of user funds, maintaining project integrity, and fostering a culture of responsibility and transparency.

Hacks that have happened in the recent past shows just how crucial it is for a project to get audited before being deployed on the mainnet.

Never compromise with your security, anon.