> curl -X POST target.co.uk/api/v2/admin --header "Authorization: Bearer *"_
Your API is your digital handshake with every partner, customer, and system you integrate with. A broken handshake doesn't just lose a deal — it exposes everything behind it. We test the handshake before someone else breaks it.
Here's the uncomfortable truth about APIs: they're designed to be consumed by machines, not humans. Which means nobody's watching. There's no pretty login page, no visible form field, no user interface that makes a vulnerability obvious. APIs are the plumbing behind your digital presence — and most organisations have never had a human being actually try to break them.
That's a remarkable asymmetry of risk. Your APIs handle the same sensitive data as your web applications — customer records, payment information, authentication tokens — but they receive a fraction of the security scrutiny. Attackers know this. It's why API attacks have become the single fastest-growing attack vector in web security.
The cost of an API penetration test is trivial. The cost of discovering your API has been silently leaking customer data for six months is not. This isn't a technology decision — it's a decision about whether you'd rather find the problem or have someone find it for you.
Modern applications aren't monoliths — they're ecosystems of interconnected APIs. Your mobile app talks to your backend API. Your backend talks to payment processors, CRMs, analytics platforms, and third-party services. Each integration is a trust boundary. A vulnerability in one API doesn't just compromise that endpoint — it can cascade across your entire ecosystem. The organisations that test their APIs aren't spending money; they're avoiding spending dramatically more later.
We test APIs regardless of protocol or architecture. If it accepts a request and returns a response, we'll find out what happens when that request isn't what your developers expected.
Our API testing methodology is built on the OWASP API Security Top 10, extended with manual testing techniques that reflect how real attackers target APIs in the wild.
Every engagement includes systematic testing against the complete OWASP API Security Top 10:
| ID | Vulnerability | What We Test |
|---|---|---|
| API1 | Broken Object Level Authorisation | Can users access other users' objects by manipulating IDs? |
| API2 | Broken Authentication | Weak tokens, missing MFA, credential stuffing, token leakage. |
| API3 | Broken Object Property Level Authorisation | Mass assignment, excessive data exposure in responses. |
| API4 | Unrestricted Resource Consumption | Missing rate limits, resource-exhausting queries. |
| API5 | Broken Function Level Authorisation | Can regular users call admin endpoints? |
| API6 | Unrestricted Access to Sensitive Business Flows | Automated abuse of business-critical operations. |
| API7 | Server-Side Request Forgery (SSRF) | Can the API be tricked into making internal requests? |
| API8 | Security Misconfiguration | CORS, verbose errors, unnecessary HTTP methods, debug endpoints. |
| API9 | Improper Inventory Management | Shadow APIs, deprecated endpoints, undocumented versions. |
| API10 | Unsafe Consumption of APIs | Trusting third-party API responses without validation. |
A penetration test captures your API's security posture at a point in time. But APIs evolve with every sprint — new endpoints, changed parameters, updated dependencies. Yesterday's secure endpoint can become today's vulnerability with a single code change.
For continuous monitoring of your API traffic and real-time threat detection, see our SOCinaBox managed SOC service. Combine periodic penetration testing with 24/7 monitoring to ensure your APIs stay secure between assessments.
Pair annual API penetration testing with SOCinaBox for continuous API traffic monitoring, anomaly detection, and automated alerting on suspicious request patterns. The pen test finds the structural weaknesses. The SOC catches the exploitation attempts in real time.
Every engagement starts with a free scoping call. Share your API documentation — or don't — and we'll tell you exactly what we'd test, how long it takes, and what it costs. The only risk is not picking up the phone.