7 Best Smart Contract Audit Firms in 2026
Compare the best smart contract audit firms in 2026: OpenZeppelin, Trail of Bits, Zellic, ChainSecurity, Cyfrin, Sherlock and CertiK, by audit model and ecosystems.
Updated July 2026 · Reviewed by the PipeFlare team
The best smart contract audit firms help Web3 projects identify vulnerabilities in their codebase. This comparison reviews seven security firms based on audit models, supported ecosystems, and in-house testing tooling. An audit reduces risk but never removes it entirely. Every vendor evaluated operates on a custom quote basis, and audit scopes vary by engagement.
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OpenZeppelin
Best for: Best for EVM and multi-chain protocols
OpenZeppelin provides manual security reviews assigning at least two researchers to every line of code. Its four-stage process includes pre-audit tooling, fuzzing, and fix verification. The firm audits Solidity, Cairo, Rust, and Go across multiple networks.
Strengths
Two researchers review every line
Four-stage process includes fix review
Supports Solidity, Cairo, Rust, and Go
Limitations
Pricing is not published online
Requires submitting a quote request
Pricing: Not published; request a quote
Trail of Bits
Best for: Best for invariant testing and open-source tooling
Trail of Bits uses internal tools like Slither, Echidna, and Medusa on every engagement. Operating since 2012, the firm offers comprehensive code assessments and design reviews across EVM, Move, Cosmos, and Solana.
Strengths
Employs Slither, Echidna, and Medusa
Covers EVM, Move, Solana, and Cosmos
470 public blockchain engagements logged
Limitations
No publicly listed pricing tiers
Requires requesting a quote or booking office hours
Pricing: Not published; request a quote
Zellic
Best for: Best for applied cryptography and zero-knowledge circuits
Zellic focuses on security assessments for blockchain systems, applied cryptography, and zero-knowledge circuits. The firm combines formal verification, fuzzing, and static analysis across EVM, Move, Solana, and Cosmos architectures.
Strengths
Specialized in zero-knowledge circuits
Uses formal verification and fuzzing
Public archive of completed reports
Limitations
Does not publish standard rates
Requires requesting a quote
Pricing: Not published; request a quote
ChainSecurity
Best for: Best for DeFi protocol reviews
ChainSecurity is run by Decentralized Security AG in Zurich and has worked with clients since 2017. The firm conducts smart contract audits for DeFi protocols, research institutions, and large organizations, maintaining a public report archive.
Strengths
Audited protocols like Aave and Compound
Public archive of audit reports
Operating continuously since 2017
Limitations
Public chain support list is limited
Quotes require direct outreach
Pricing: Not published; request a quote
Cyfrin
Best for: Best for multi-chain audits and developer tooling
Cyfrin provides smart contract audits alongside tools like Solodit, Aderyn, and Moccasin. The firm lists coverage across 17 distinct blockchains and holds SOC 2 Type II compliance, offering manual code analysis paired with mitigation support.
Strengths
Lists 17 supported blockchain networks
Develops tools like Solodit and Aderyn
Maintains SOC 2 Type II compliance
Limitations
Pricing is strictly quote-based
Must book a consultation to scope
Pricing: Not published; request a quote
Sherlock
Best for: Best for combining collaborative audits with competitive contests
Sherlock offers collaborative audits with curated security teams as well as open audit contests with independent researchers. The platform includes an AI-native review engine and live bug bounties to identify vulnerabilities.
Strengths
Offers both team audits and open contests
Network of over 11,000 researchers
Integrated bug bounty management
Limitations
Does not list supported chains on homepage
Pricing is quote-dependent
Pricing: Not published; request a quote
CertiK
Best for: Best for compliance solutions and broad security assessments
CertiK provides code audits, penetration testing, and regulatory compliance packages such as DORA and MiCA. Holding SOC 2 Type II and ISO 27001 certifications, the firm reports serving 5,500 clients per its site.
Strengths
Holds SOC 2 Type II and ISO 27001
Provides regulatory compliance solutions
Formal verification capabilities
Limitations
Homepage omits a specific chain list
No public baseline pricing
Pricing: Not published; request a quote
Summary comparison
| Option | Best for | Audit model | Ecosystems named | Pricing |
|---|---|---|---|---|
| FeaturedYour company here, pinned above every listing Get featured → | ||||
| OpenZeppelin | EVM and multi-chain protocols | Private team review | Arbitrum, Base, Ethereum, Linea, Optimism, Sui, ZKsync | Not published; request a quote |
| Trail of Bits | Invariant testing and tools | Private team review | Ethereum, Aptos, Sui, Solana, Arbitrum, Cosmos, TON | Not published; request a quote |
| Zellic | ZK circuits and cryptography | Private team review | EVM, Aptos, Sui, Cosmos, Solana | Not published; request a quote |
| ChainSecurity | DeFi protocol reviews | Private team review | Solana tagged; does not clearly list other supported chains | Not published; request a quote |
| Cyfrin | Multi-chain audits and tools | Private team review | Ethereum, Arbitrum, Solana, Sui, Aptos, 17 total | Not published; request a quote |
| Sherlock | Collaborative reviews and contests | Team review and contests | Not listed on homepage | Not published; request a quote |
| CertiK | Compliance and security assessments | Private team review | Not listed on homepage; case studies cite XRP, TON, Sei | Not published; request a quote |
| Cantina | Onchain audits plus bounties | Hybrid audits with Spearbit researchers and AI review | Not published | Not published; request a quote |
| QuillAudits | DeFi, RWA, wallet and L1 audits | Researcher squad of 10-12 per audit | 12 chains incl. Solana, Sui, Aptos | Not published; request a quote |
| Hashlock | Solidity, Rust, Vyper, Move audits | Manual audits, pentesting, bug bounty setup | Ethereum, Solana, Bitcoin, Sui, Aptos, others | Not published; request a quote |
| SlowMist | Exchange, wallet and chain audits | White-box source audit; threat intelligence | Not published | Not published; request a quote |
| Halborn | Smart contract and L1 assessments | Assessments, pentests and advisory | Solana, Sui, Cosmos, Near, Avalanche, others | Not published; request a quote |
| Veridise | ZK and zkVM audits | Audits with in-house Vanguard and OrCa tools | zkSync, Linea, Aztec, Scroll, Stellar | Not published; request a quote |
| BlockApex | Multi-chain audits and tokenomics | Manual audits; Slither, Echidna, Certora used | 26 chains incl. Ethereum, Solana, TRON | Not published; request a quote |
| Quantstamp | Audits plus operational security | Audits, Blitz accelerated reviews, OpSec | Ethereum, Solana, Polygon, Avalanche, Arbitrum | Not published; request a quote |
| HackenProof | Crowdsourced audits and bounties | Private, crowdsourced and DualDefense audits | Not published | Not published; request a quote |
| Cyberscope | Token audits, KYC and monitoring | Manual audits plus Cyberscan AI tool | Ethereum, BNB Chain, Polygon, Solana, TON | Not published; request a quote |
| Audita | Sector-specific manual audits | Manual audits; free automated audit tool | Not published | Not published; request a quote |
| AuditOne | Audits via independent auditor teams | Handpicked independent auditors per project | Not published | Not published; request a quote |
| Nethermind | Cairo, Solana, ZK and Noir audits | Audits with partial reports during engagement | Ethereum, Starknet, Solana, Noir | Not published; request a quote |
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How the Audit Firms Differ
The seven firms differ mainly in audit model, the ecosystems each names, and in-house tooling. OpenZeppelin, Trail of Bits, Zellic, ChainSecurity, Cyfrin, and CertiK structure their primary services as private team engagements, where dedicated researchers assess code against a defined scope. Sherlock combines this approach with open competitive contests, allowing independent researchers to review contracts simultaneously alongside curated teams. Ecosystem coverage also separates these providers. Cyfrin explicitly names 17 blockchains including Ethereum, Solana, Sui, Aptos, and Monad. OpenZeppelin lists platforms such as Ethereum, Arbitrum, Base, Starknet, and Sui, reviewing code written in Solidity, Cairo, Rust, and Go. Trail of Bits and Zellic support EVM alongside Move-based chains like Aptos and Sui, Solana, and Cosmos, whereas ChainSecurity, Sherlock, and CertiK highlight specific protocol engagements rather than exhaustive network compatibility rosters. Internal tooling creates another point of distinction. Trail of Bits builds and deploys Slither, Echidna, and Medusa on every assessment. Cyfrin provides tools such as Aderyn, Moccasin, and the Solodit vulnerability database. OpenZeppelin relies on a proprietary Code Inspector during pre-audit checks, while Zellic pairs static analysis with formal verification and fuzzing.
What an Audit Covers and What It Does Not
A smart contract audit provides a point-in-time review of a defined codebase scope. Researchers inspect code logic to identify security vulnerabilities. An audit does not guarantee that a smart contract is safe or entirely free of bugs. A security review reduces risk, but it never removes risk entirely. Engagements can include a fix review stage after the initial findings report is delivered. Firms such as OpenZeppelin and Cyfrin review remediations deployed by the development team. OpenZeppelin, for example, delivers its final report through a dedicated platform following fix review.
Questions to Ask Before Hiring
Clarify the precise technical scope, target languages, and named ecosystems before requesting a proposal. Project teams should verify whether the firm has verified expertise in the specific framework of the project, whether that is Solidity on Ethereum, Rust on Solana, or Move on Sui. Confirming which languages the firm actively audits prevents mismatches during onboarding. Ask how the firm handles fix reviews and report publication. Inquire whether the quoted price includes a secondary review of remediated code or if fix verification requires an additional fee. Teams should also establish whether the final report will be published in a public archive, such as those maintained by Zellic, ChainSecurity, and Cyfrin, or kept private. Establish the quote basis and delivery timeline early in discussions. Because none of the top audit firms publish fixed rates, every engagement is quote-based. Confirming team allocation, such as OpenZeppelin's standard structure of two or more researchers and a technical manager, helps teams evaluate what the proposal includes.
Private Audits Versus Contests
Private audits and competitive contests represent two distinct methodologies for smart contract security reviews. OpenZeppelin, Trail of Bits, Zellic, ChainSecurity, and Cyfrin emphasize private team engagements. In this model, an assigned team of security researchers reviews code and documentation against a defined scope. Competitive contests crowdsource vulnerability discovery across an open network of researchers. Sherlock provides both models, allowing protocols to commission collaborative audits with curated teams or host public audit contests featuring hundreds of independent participants. In an audit contest, hundreds of independent researchers compete openly to discover vulnerabilities.
The verdict
OpenZeppelin stands out for projects needing multi-chain and EVM code reviews backed by a structured four-stage audit process. Trail of Bits is best for teams seeking invariant testing using internal tools like Slither and Echidna. Zellic is the top pick for applied cryptography, secure enclaves, and zero-knowledge circuit assessments. For projects wanting both collaborative reviews and open crowdsourced competitions, Sherlock provides both options.
Frequently asked questions
What do smart contract audit firms do?
Smart contract audit firms conduct security reviews of blockchain code. Researchers use manual inspection, static analysis, fuzzing, and formal verification to detect logic bugs and security vulnerabilities. They deliver a report outlining findings and identified vulnerabilities.
How much does a smart contract audit cost?
None of the seven major smart contract audit firms publishes standard prices online. Costs are entirely quote-based across all evaluated firms. Teams must request a quote or book a consultation directly with each firm.
Does an audit guarantee a contract is safe?
No, an audit does not guarantee that a contract is safe or completely free from vulnerabilities. A security review is a point-in-time assessment of a specific code snapshot that reduces risk but cannot eliminate it entirely.
What is the difference between an audit and a contest?
A private audit assigns a dedicated team of security engineers to review code systematically over an agreed schedule. An audit contest opens the codebase to a broader community of independent researchers in an open competition. Sherlock offers both private collaborative reviews and competitive contests.
How do I compare audit firms?
Compare firms by matching their verified experience to your project's programming language and target blockchain. Review public audit archives, such as those published by ChainSecurity or Zellic, to inspect the depth of their technical reports. Finally, confirm whether the proposal includes in-house tooling, dedicated project management, and fix review stages.
Sources
- OpenZeppelin official site
- Trail of Bits official site
- Zellic official site
- ChainSecurity official site
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