The best API security tools help you find every API you run, test them for flaws such as broken authorisation, and protect them from attacks in production. Some focus on testing in the development pipeline, others watch live traffic, and many now cover AI agents and MCP servers too. Eleven options follow in no particular order.
APIs are how apps, partners and now AI agents talk to your systems. They're also where attackers look first, because a single missing check can expose every customer record at once.
The eleven tools below are listed alphabetically and in no particular order, and every description comes from the vendor's own website, read this week. My piece on how API testing tools help developers covers the functional testing side.
API security tools side by side
I checked the free plan column on each tool's own website, as of Oct 2026. Yes means the site names a free plan, a free version, a free edition or an open source edition. Trial only means a time-limited trial. Not stated means the pages I read named neither, even where there's a button inviting you to try it, so check the vendor's page before you sign up.
| Tool | Type | Good for | Free plan |
|---|---|---|---|
| 42Crunch | API security platform | OpenAPI contract-based testing | Trial only |
| Akamai API Security | API discovery and protection | Every API from legacy to AI | Not stated |
| APIsec | API security testing | Automated API pen testing | Not stated |
| Cequence | Application and API protection | Application and API protection | Not stated |
| Data Theorem | AppSec and API security | Mobile apps and their APIs | Not stated |
| Escape | AI offensive security platform | Testing modern apps and APIs | Not stated |
| Levo.ai | API and AI security platform | Shifting API security left | Not stated |
| Salt Security | API and AI security | Large API estates and MCP | Not stated |
| StackHawk | Dynamic testing for developers | Testing APIs in the CI pipeline | Not stated |
| Traceable | Application and API security | Enterprise-scale API protection | Not stated |
| Wallarm | Unified WAAP platform | APIs and web apps together | Not stated |
Eleven API security tools worth a look
42Crunch
Best for: Developers who want API security testing and protection built around OWASP API Top 10 risks and API contracts, with a free trial.
Akamai API Security
Best for: Enterprises who want to discover, test, govern and protect every API, with visibility across traffic, code and data.
APIsec
Best for: Teams who want automated API security testing and exploit validation, including daily penetration tests of their applications.
Cequence
Best for: Businesses who want advanced application, API and AI protection from one specialist vendor rather than several tools.
Data Theorem
Best for: Teams shipping mobile and cloud-native apps who want API security alongside mobile and cloud application security.
Escape
Best for: Engineering teams who want AI agents that discover and test exposure across modern applications, APIs and infrastructure.
Levo.ai
Best for: Product teams who want API and AI security that runs from development through to runtime without slowing releases.
Salt Security
Best for: Enterprises with large API estates who want API security plus discovery of MCP servers and AI agents.
StackHawk
Best for: Developers who want to test their running app and APIs inside the coding workflow, including code written by AI agents.
Traceable
Best for: Large organisations who want intelligent application and API security that works at enterprise scale.
Wallarm
Best for: Organisations who want one web application and API protection platform covering APIs, AI and web apps.
Where to start
- Testing in the developer pipeline: StackHawk or 42Crunch.
- Automated API pen testing: APIsec or Escape.
- Large API estates and MCP discovery: Salt Security or Akamai API Security.
- Enterprise runtime protection: Traceable or Cequence.
- APIs and web apps together: Wallarm.
- Mobile apps and their APIs: Data Theorem.
- From development to runtime: Levo.ai.
The top API risk is a logic gap
OWASP's API Security Top 10 for 2023 lists API1:2023 Broken Object Level Authorization first, followed by Broken Authentication and Broken Object Property Level Authorization.
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Broken object level authorization means a user can reach someone else's data just by changing an ID. Generic scanners struggle to spot it, so look for tools that understand your API's business logic and test with real user roles.
Testing tools or runtime protection?
Testing tools scan APIs before release, ideally on every build. They catch flaws early, when fixing them is quick and nobody outside has seen them.
Runtime protection watches live traffic, discovers APIs you didn't know about and blocks attacks. Most mature teams end up with both, starting wherever their biggest gap is.
AI agents add a new twist. They'll call your APIs on a user's behalf, often faster and more often than a person would, so it's worth asking each vendor how it tells a legitimate agent from an attacker using the same keys.
Questions to ask before you choose
- Do we know every API we expose today?
- Does it test authorization with real user roles?
- Can it run in our CI pipeline?
- Does it cover GraphQL as well as REST?
- Can it watch AI agent and MCP traffic?
- How are findings routed to developers?
If you've secured APIs for a living, the technology guest post guidelines explain what I'd like to see in a pitch.
Signs your APIs need attention
- Nobody has a full API list. Run discovery.
- Old API versions still answer. Retire them.
- Tests skip authorization. Add role-based tests.
- Partners call APIs directly. Monitor that traffic.
Do you make API security or application security tools? Tool makers can ask to be considered for a featured place on this list.
My plain advice on API security tools
Start with discovery. You can't secure APIs you don't know about, and most organisations find more than they expected, including old versions nobody switched off.
Then test authorization on your most sensitive endpoints with two real user accounts. If you're planning wider security testing, my roundup of penetration testing tools covers the rest of the stack.
Frequently asked questions
What is API security?
It's the practice of finding, testing and protecting APIs so attackers can't misuse them to reach data or functions they shouldn't.
What is the biggest API security risk?
OWASP's API Security Top 10 for 2023 puts Broken Object Level Authorization first.
Do I need runtime protection if I test my APIs?
Testing catches flaws before release, while runtime tools find unknown APIs and block live attacks, so many teams use both.
Can API security tools run in CI?
Yes. Several tools test APIs on every build so developers get findings before code ships.
Do API tools cover AI agents?
Some now discover MCP servers and AI agents, because agents call APIs on behalf of users.
Is there free API security software?
Some vendors offer free trials, and open source scanners can help with basic testing.
