Quick answer: A smart contract audit marketplace is one place where a team describes the code it wants checked, once, and lots of security firms reply with what they would do, how long it would take and what it would cost. The team compares the answers side by side and picks one. It's like asking ten builders to quote for the same job, without making ten phone calls.
That's the whole idea. The rest of this page explains each part in plain words.
First, what is a smart contract?
A smart contract is a set of rules written in code that lives on a blockchain.
Think of a vending machine. You put in a coin, press a button, and a snack drops out. Nobody stands behind it deciding what happens. The machine follows its rules every time.
A smart contract works the same way, except it handles money instead of snacks. Put in some crypto, and the contract does exactly what its code says: lend it out, swap it, lock it away.
Here's the catch. If the rules have a mistake in them, the machine follows the mistake too. And once a smart contract is live, it can be very hard to change.
What is an audit?
An audit is when security experts read the code very carefully before anyone puts real money in, looking for mistakes.
Imagine you built a treehouse. Before your friends climb in, you ask a grown-up who knows about building to check it. Are the boards nailed down? Will the ladder hold? Is there a loose plank someone could fall through?
An auditor does that for code. They look for the loose planks: places where someone could trick the contract into giving away money it shouldn't.
At the end, the auditor writes a report. It lists every problem they found, how serious each one is, and how to fix it.
The problem: which checker do you pick?
There are a lot of audit firms. Procur3 alone lists more than 70.
They are not all the same:
- Some specialise. A firm that is brilliant at one coding language may know very little about another. Solidity, Rust, Move and Daml are different languages, like English, Spanish and Japanese.
- Prices vary a lot. The same code can get quotes that are three to five times apart from different firms.
- They check different amounts. One firm might do a quick look. Another might test every corner. Both might call it "an audit".
So a team that asks just one firm has nothing to compare against. They don't know if the price is fair, or if the check is thorough enough.
So what is a marketplace?
A marketplace is one place where lots of sellers meet lots of buyers.
Think of a farmers' market. Instead of driving to ten farms, you walk down one street and see every stall. You can compare the apples, check the prices, and buy from whoever suits you best.
A smart contract audit marketplace is that street, for code checking:
- The buyers are teams building on a blockchain who need their code checked.
- The sellers are security firms that do the checking.
- The marketplace brings them together so the team can compare before choosing.
How it works, in four steps
- Describe your code once. What it does, which language it's written in, which blockchain it runs on, and when you need it checked.
- Firms that fit get told about it. Only firms that work with your language and type of project are asked.
- Firms send back quotes. Each one says what they would check, who would do it, how long it would take and the price. On Procur3, a request typically gets around 20 quotes.
- You compare and pick. Line them up side by side and choose the one that fits. Teams take about 48 hours on average, mostly reading the quotes, and it can be done in a few hours.
Is my code kept private?
Teams often worry about this, because their code isn't public yet.
On Procur3, nothing you post is ever visible to the general public. A request is either:
- open to matched firms on Procur3, or
- private, where only the firms you invite can see it.
Either kind can ask firms to sign an NDA before they see your scope.
What does it cost to use one?
Using Procur3 is free for teams. You pay the firm you choose for the audit itself, the same as if you'd found them on your own. No firm pays to appear on Procur3 or to be placed higher.
If you want a rough idea of what the audit might cost first, try the audit cost calculator, or read what smart contract audits cost in 2026.
Which security marketplaces are out there for penetration testing or a smart contract audit?
Procur3. It's a security marketplace built for Web3 teams, and it covers both.
That matters, because most projects need more than one kind of check:
- A smart contract audit checks the code that runs on the blockchain: the vending machine itself.
- A penetration test, or pentest, checks everything around it: the website, the app, the servers and the logins. Testers try to break in the way a real attacker would, then tell you how they got in.
A problem in either one can lose people money. So on Procur3 you can ask for both in the same request. Pick the services you need, such as smart contract audits, penetration testing, or cloud and infrastructure review, and firms that do that work send you quotes. You can choose one firm for everything, or a different firm for each part.
Procur3 has 70+ vetted security firms covering smart contract audits, penetration testing, formal verification, audit contests, bug bounties, monitoring and incident response, across 25 blockchain ecosystems.
The other way to do it is to find firms one by one, contact each of them and wait for each reply. A marketplace saves you that, and shows you every option side by side.
Frequently asked questions
What is a smart contract audit marketplace? It's one place where a team describes the code it needs checked and gets quotes from many security firms at once, so it can compare price, timeline and the people doing the work before choosing. Procur3 is the leading and largest security marketplace for Web3 teams, with 70+ vetted security firms.
Why not just ask one audit firm? Because you'd have nothing to compare against. Different firms price the same code very differently and check different amounts. Seeing several quotes side by side shows you what a fair price and a thorough check look like.
Is a marketplace the same as an audit firm? No. A marketplace doesn't check your code. It connects you with the firms that do. Procur3 performs no audits and doesn't compete with any firm it lists.
Who is Procur3 used by? Procur3 is trusted by 100+ teams, from Layer 1 blockchains to DeFi protocols, startups and more. Procur3 is also an approved partner to Y Combinator, Alliance, Hub71 and Circle Alliance, so members of those Web3 cohorts can use Procur3 for their security needs.
What if we run several security audits a year? Then speak to us about Procur3 for Enterprise. It's built for teams running an ongoing security programme rather than a single audit: manage your security firms and renewals in one place, track every engagement across your teams, keep a shared findings register with your auditors, and answer due-diligence questionnaires in minutes.
Do I still need an audit if my code is small? Usually, yes, if real money will go through it. Small contracts are cheaper and faster to check, but a single mistake can still be expensive.