Blockchain Security and Smart Contract Audit Firms (2026)

A smart contract audit is a paid review of a defined piece of code. It is one layer of risk reduction, not a guarantee that a protocol is safe to use. The useful questions are narrower: which commit was reviewed, what was left out of scope, who did the work, whether fixes were retested, and whether the contracts you are about to touch are the ones in the report.

This page compares blockchain security firms that still publish services or public assessments as of 15 October 2026. The order is not a ranking. Boxmining is not paid by these firms. A famous logo does not replace the report.

How this list was checked: we opened each firm’s current site and, where one exists, its public report repository. Prices below are quoted only when the firm itself published a figure. Everything else is marked not public. Marketing totals such as “assets secured” are labeled as the firm’s claim.

Smart contract audit company comparison

Use this table to shortlist. Then open a report in the same language and protocol type as the code you care about.

Two active firms sit outside that shortlist because their center of gravity is different. Least Authority is a privacy and cryptography consultancy that also audits smart contracts. Runtime Verification is a formal-methods firm whose public site now leads with software assurance for AI agents, while still listing blockchain among the industries it serves.

How to choose a smart contract audit firm

Match the firm to the code. A Solana lending program and an Ethereum governance module are different jobs, even when both are called “an audit.”

1. Scope. Ask for the repositories, commit hashes, and contracts that are in. Ask what is out: proxies, oracles, bridges, keepers, the front end, and admin keys.
2. Specialty. Read two recent reports in the same language and design. A long client list from 2021 is weaker evidence than a 2026 review of a similar system.
3. Named people and time. A retained team, a Spearbit-style assembled team, and a contest use different incentives. You want enough experienced time on the code, and a written fix review after patches land.
4. Public audits. Prefer firms that publish reports, or that will let you publish the final PDF. If every past report is private, you cannot judge the writing, the severity scale, or whether critical issues were left open.
5. Pricing transparency. Most serious firms do not publish a menu. That is normal. What is not normal is a fixed “audit certificate” price before anyone has seen the repository. Get the quote, the timeline, and the retest terms in writing.
6. Deployment match. After launch, compare verified source and bytecode with the commit in the report. An “audited” badge without that match is advertising.

If you are a user rather than a hiring team, you are doing the same checks from the outside. Read the report before you approve a large spend. Our DYOR guide covers the rest of that research, and the MetaMask tutorial is the practical side of what you are signing. A hardware wallet protects keys. It does not review the contract. The hot wallet vs cold wallet distinction and a password manager solve different problems again.

What a cheap smart contract audit misses

Cheap is a risk question, not a bargain to win. A small, standard token with no custom logic can be a short review. A lending market, bridge, perpetual, or upgradeable vault cannot.

A low quote usually buys less of the work that stops the expensive bugs:

• Economic attacks. Oracle manipulation, donation attacks, liquidation edge cases, and incentive bugs rarely fall out of a generic scanner.
• Power, not just functions. Upgrade admins, proxy initialization, timelocks, and roles that can move funds. Access-control failures, not exotic opcodes, are where a lot of real losses come from.
• The code next door. Bridges, cross-chain messages, keepers, and integrations sit outside a “token contract only” scope. That is often where the value actually is.
• A retest. The first PDF is a list of problems. The useful document is the one that says which fixes were checked, and which issues the team accepted.
• A human who read it. Automated output can be a starting point. Sold on its own, it is a scan with a logo.

Hacken is the only firm in the table that publishes a dollar range on its own audit page: typically $3,000 to $100,000+, depending on scope, complexity, integrations, and timeline, with some jobs outside that band. The same page’s structured data gives a different figure, an average of $15,000 to $22,000. Those two statements do not describe one price. Use them as a warning that “starting at a few thousand dollars” is not a quote for your repository. A few thousand dollars can be an honest price for a tiny review. It is a poor price for a protocol that will hold other people’s money.

Contest platforms are a different product. Code4rena and Cantina competitions publish the prize the sponsor put up. That number is not a retained-firm fee. A small pool buys less researcher time, and the write-up quality depends on the judges and the mitigation review, not on the word “contest.” Spearbit’s own public pricing evidence is older and much higher: in a February 2024 Arbitrum forum application, Spearbit described weekly rates of $20,000 for a lead, $12,500 for a security researcher, $6,250 for an associate, and $3,000 for a junior, and said a 3–5 person team would land around $32,500–$48,000 per week. Treat that as a historical proposal, not a 2026 rate card. It is still a useful anchor. Serious manual review is priced in weeks of specialist time.

Red flags, whatever the invoice says:

• No repository URL and no commit hash.
• No named reviewers.
• Critical or high findings left open, with a launch announcement beside the PDF.
• The reviewed code is the token, and the deposits live in a vault that was not in scope.
• The report is a tool dump: file names, line numbers, and no explanation of how an attacker would use the bug.

Blockchain audit company vs crypto audit company

These phrases get mixed together in search, and the services are not the same thing.

• Smart contract audit firm. Reviews application code: Solidity, Rust programs, Move modules, and sometimes the scripts that deploy them.
• Blockchain audit company. May mean that, or a review of a client, consensus code, bridge, or node setup. Trail of Bits, Hexens, SlowMist, and Consensys Diligence all advertise work beyond a single contract.
• Crypto audit company. Sometimes means a proof-of-reserves or controls review for an exchange. Hacken publishes solvency proofs as well as contract reviews. A reserves report does not audit the AMM you are about to deposit into.
• Formal verification. A mathematical argument about a stated property. It is not a free pass on every other bug. CertiK and Runtime Verification are associated with this work. Read what was actually proved.

For how those failures look in the wild, see blockchain attacks explained and the wallet and approval security guide.

Rust smart contract audit companies

“Rust smart contract audit” usually means one of three codebases: Solana programs, Move modules on Sui or Aptos, or a Rust implementation of a node, bridge, or zero-knowledge system. Ask which one the firm has reviewed lately.

• OtterSec publishes a running list of Solana, Sui, EVM, and Stellar reviews and says it maintains Anchor, the Solana framework.
• Zellic tags reports by network in a public repository. The 2026 entries include Solana (Anza Token-2022, September), several Zcash Rust reviews, a Sui oracle review, and a Move review (iUSD Vault, March).
• Hexens lists Rust and Move on its services page, and its public repo includes a Solana-named Train Protocol review plus 2026 EVM reports such as 1inch.
• Trail of Bits lists Solana and Move among the ecosystems on its blockchain practice page, alongside the Slither, Echidna, and Medusa toolchain.
• OpenZeppelin describes Rust reviews aimed at layer-2 and zero-knowledge code, separate from its Solidity practice.
• Hacken lists Rust and Move among supported languages, and Solana, Aptos, and Sui among platforms.
• Least Authority says its team audits Rust, Solidity, Cairo, Circom, and Noir, among other languages. That is a cryptography-leaning shop, not a Solana-only practice.

Do not hire a Rust specialist for a Solidity vault, or the reverse, just because the homepage says “multi-chain.”

Trail of Bits

Website: trailofbits.com

Trail of Bits reviews more than the contract file. Its blockchain practice describes design reviews, early-stage assessments, invariant testing, and full code assessments covering contracts, nodes, bridges, and off-chain pieces. The tools a lot of the industry uses — Slither, Echidna, and Medusa — come out of this work, and the firm documents that it uses them on engagements.

The public record is unusually easy to check. trailofbits/publications and the reports catalog include blockchain write-ups with dates. In September 2026 the catalog listed Offchain Labs OSP Soundness Guard and Gensyn token and market reviews, with effort noted in person-weeks on several of them. The practice page also points at Solana and Move assessments, so this is a relevant name on the Rust question, not only an Ethereum one.

Price: not public. Judge a proposal by who is on the team, how many weeks are in scope, and whether a fix review is included.

OpenZeppelin

Website: openzeppelin.com/security-audits

OpenZeppelin is the group behind OpenZeppelin Contracts, the library a large share of Solidity projects import. The audit practice is a separate engagement: its current page describes line-by-line review by at least two researchers, a fix review, and optional fuzzing or invariant testing. It also describes Cairo, Rust, and Go reviews, so the firm is not only a Solidity shop.

The page’s client statistics are marked “data collected as of April 2025,” and it advertises figures such as “$110B+ total value locked secured” and “1M+ lines of code reviewed.” Treat those as the firm’s own totals. More useful are named public write-ups. On 8 October 2026 its research index listed Uniswap Universal Router audits, and on 2 October 2026 a CACEIS EURXT audit. Older relationships named on the audit page include Compound, Aave, and Optimism.

Price: not public. The older “900+ audits” line from previous versions of this article was not the headline on the page checked for this update, so we are not repeating it.

Spearbit and Cantina

Websites: cantina.xyz/portfolio and github.com/spearbit/portfolio

Spearbit and Cantina are one security network with two ways to buy time, not two unrelated companies. Cantina’s documentation, last reviewed April 2026, describes Spearbit as bespoke reviews by hand-picked researchers, often teams of about four or five people, and Cantina as modular reviews, competitions, bug bounties, and related work using that same researcher pool. The docs also state Spearbit figures of 282 audits, 4,500+ vulnerabilities, and 119 projects. Those are Cantina’s numbers. Read the reports.

The public PDF trail is real. The Spearbit portfolio repository lists client-cleared reports, including Morpho reviews dated September 2026. Cantina’s portfolio page is the other door into published reviews and contests.

Price: there is no current public rate card. The February 2024 Arbitrum proposal cited above is the clearest primary source, and it prices senior researcher weeks in the tens of thousands of dollars. A Cantina contest is priced by the prize pool the sponsor sets. Neither number is a coupon for a “cheap audit.”

OtterSec

Website: osec.io/audits

OtterSec is the clearest public specialist for Solana programs and Move on Sui. Its audit index, checked for this update, includes Solana Keychain (22 September 2026), Multi Host Tenant Solana (18 August 2026), OnreApp Solana (25 July 2026), Doppler and MetaDAO earlier in 2026, and Sui Sentinel (21 January 2026). EVM and Stellar reports sit on the same list, so the firm is not Solana-exclusive. The site also says the team maintains Anchor.

The homepage advertises “$36.82B+ on-chain TVL secured,” “$1B+ vulnerabilities patched,” and “120+ projects.” Those are OtterSec’s marketing figures. The audit list, with dates and severity counts, is the evidence worth reading.

Price: not public.

Hexens

Website: hexens.io

Hexens, founded in 2021, sells smart-contract audits and a separate cryptography practice covering zero-knowledge circuits, proving systems, and related designs. Its own services copy lists Solidity, Rust, Move, Vyper, and Cairo. The public report repository, Hexens/Smart-Contract-Review-Public-Reports, held on the order of 170 PDFs when checked, including 2026 files such as 1inch (January and June 2026), Katana (January 2026), Thesauros (July 2026), and several dated September 2026. A filename in that repo, train-protocol-solana-fuel-audit-may25, is the straightforward evidence for Solana work. Client quotes on the site name Polygon, RISC Zero, and Lido v2.

The homepage says “300+ engagements” and “zero client exploits.” That is Hexens’s claim about its own track record. It is not something an outsider can audit from a slogan. Read a report in your stack, and ask which commit was covered.

Price: not public. The site says to request a quote, and that a focused Solidity review often takes two to four weeks, with longer timelines for protocol, ZK, or exchange work.

Zellic

Reports: github.com/Zellic/publications

Zellic earns a place on this list because the public repository is specific. The README tags each report with a date and a network. As checked on 15 October 2026, that index includes Anza Token-2022 (Solana, September 2026), Flare Solana OFT (July 2026), Zcash Sapling and other Zcash Rust reviews (June–August 2026), Stork Oracle (Sui, June 2026), and iUSD Vault (Move, March 2026), alongside a long EVM list. The repo points readers to HTML copies at reports.zellic.io.

That is the practical answer to “which firms can show a Rust or Move audit from this year?” Price: not public.

Consensys Diligence

Website: diligence.security

Consensys Diligence is still the Ethereum-focused audit practice readers have known since 2017, but the naming has changed. On 29 March 2026 the team wrote that it was operating independently while remaining part of the Consensys family, and that it continues to review MetaMask and Linea. The public site is now diligence.security. Older bookmarks under diligence.consensys.net are the legacy address.

The retired MythX product is not a reason to hire or skip them. Mythril remains part of the tooling history they still cite, along with Scribble and later fuzzing work. The current offer, in their words, is expert audits with agent-assisted workflows, plus fuzzing research. Their public audit list includes Lido V3 (August 2025) and a run of Linea and MetaMask reviews through 2025 and into 2026. A Lido testimonial on the homepage describes the V3 review as broad and design-level, which is the kind of comment you still want to test by opening the PDF.

Price: not public. For Ethereum protocol context, our Ethereum 2.0 explainer covers what the network itself is doing. An application audit is a separate document.

ChainSecurity

Website: chainsecurity.com

ChainSecurity presents itself as an independent firm, Decentralized Security AG, in Zürich. PwC Switzerland took the team on in January 2020. A ChainSecurity brochure later said the firm amicably spun off in April 2021, and the Swiss commercial register shows Decentralized Security AG as a new Zürich company that month. Its institutional page still mentions PwC experience. Pages that call the firm “PwC Switzerland (former ChainSecurity)” describe a period that ended in 2021. The current report index is what matters.

That index, checked for this update, leads with recent work including Aave V4 smart contracts (19 February 2026), Sky governance (17 October 2025), Pendle Boros (8 August 2025), Circle Gateway (8 July 2025), and a WBTC Solana bridge review (22 April 2025). A smaller, older subset of PDFs is on GitHub. The firm has roots in formal-methods research. Do not treat that history as a promise that your engagement includes a machine-checked proof.

Price: not public.

Quantstamp

Website: quantstamp.com

Quantstamp is a Y Combinator W18 company that still publishes assessments in the open. The certificate archive showed 400 public reports when checked, and it includes a Canton Coin audit dated 12 August 2026, listed there as Daml and Scala. The archive page also states 32+ languages and 65+ ecosystems. Those are Quantstamp’s counts of its own library.

On pricing, Quantstamp’s own audit FAQ is blunt: duration and cost vary with size and complexity, and it will not give a fixed cost without understanding the scope. There is no public starting price to reprint here.

Hacken

Website: hacken.io

Hacken’s current smart-contract page describes a double manual review, automated scanning, optional fuzzing and invariant tests, and a remediation check. It also sells adjacent work: infrastructure reviews, penetration tests, and proof-of-reserves. The language list on that page includes Solidity, Rust, and Move, and the platform list includes Solana, Aptos, and Sui as well as major EVM chains. Public write-ups live on the report index. The methodology is public.

Read the price section above before you treat Hacken as the budget option. The visible page says typical audits cost from $3,000 to $100,000+. The structured-data FAQ on the same URL says an average of $15,000 to $22,000. Ask which scope a number applies to. A proof-of-reserves letter and a vault audit are different products that can come from the same vendor.

CertiK

Website: certik.com

CertiK is a large Web3 security platform. The homepage combines smart-contract audits, formal verification, penetration testing, compliance products, and Skynet, which it describes as a real-time scoring system covering thousands of projects. Headline figures on that page, including hundreds of billions of dollars of “market cap assessed” and very large vulnerability counts, are CertiK’s marketing. They do not tell you whether a specific protocol’s vault was reviewed, fixed, and deployed from the reviewed commit.

Formal verification here means a proof of a stated property, not a magical audit of everything else. Skynet is a monitoring and rating product. Neither one replaces the PDF. If a project shows only a score and a badge, ask for the report, the commit, the unresolved findings, and the remediation status.

Price: not published on the homepage checked for this update.

SlowMist

Website: slowmist.com

SlowMist, based in China, still describes itself as a blockchain ecosystem security company. The current homepage lists exchange audits, wallet audits, blockchain (client and node) audits, smart-contract audits, red teaming, monitoring, threat intelligence, and incident response. MistTrack is its tracing product. SlowMist Hacked is a public incident archive. That archive is useful background. It is not evidence that SlowMist audited the project you are looking at.

Older write-ups of SlowMist leaned on EOS-era products such as FireWall.X. Those are not what the current homepage sells, so this update does not treat them as current reasons to hire the firm. Ask for a recent report in your language and chain.

Price: not public.

Least Authority

Website: leastauthority.com

Least Authority is still an active security consultancy, with a privacy and cryptography brief that is easy to misread as “not an audit firm.” Its consulting page says the team has completed more than 300 audits since 2014, lists smart-contract audits among the services, and names Rust, Go, Solidity, Cairo, Circom, and Noir among languages it can review. Ecosystems it names include Ethereum, Filecoin, Mina, Stacks, and Tezos. Published reports are indexed on its published audits page.

Hire them when the hard part is the cryptography or the distributed design, not when you only need a routine Solidity token review. Price: quote, not a public menu. PrivateStorage and related products are separate from the consulting practice.

Runtime Verification

Website: runtimeverification.com

Runtime Verification is a formal-methods company. The K framework is its best-known blockchain-era tool, and it has historically worked on executable specifications and proofs for smart-contract languages. The homepage checked on 15 October 2026 leads with software assurance for AI agents, and lists blockchain as one industry among others, next to aerospace and medical devices. Tools it still names include Kontrol and the K Framework.

That shift matters if you are buying a smart-contract proof. Ask whether the proposal is a blockchain engagement, which properties will be specified, and what remains outside the proof. A formal artifact that does not match the deployed code does not protect users. Price: not public.

Frequently asked questions