API Penetration Testing
APIs are how your systems quietly talk to each other in the background — most people never see them, which is exactly why they get overlooked. We test whether they actually check who's asking before handing over data.
API penetration testing, defined
API penetration testing is comprehensive adversarial testing of REST, GraphQL, and SOAP endpoints — validating authentication logic, authorization boundaries, rate limiting, and data exposure. A surprising number of APIs don't actually verify who's asking before returning data.
Because APIs rarely have a UI to eyeball, they get far less scrutiny than web front-ends — which is exactly why broken object-level authorization is consistently one of the most common critical findings we confirm.
What we test
- Broken Object Level Authorization (BOLA) — whether one user's token can access another user's data by changing an ID
- Broken authentication — weak token validation, session handling flaws across API boundaries
- Server-Side Request Forgery (SSRF) — whether an API endpoint can be tricked into making requests on the attacker's behalf
- Unrestricted resource consumption — missing rate limiting that enables abuse or denial of service
- Improper inventory management — shadow or undocumented endpoints outside your tracked API surface
Mapped to the OWASP API Security Top 10 (2023)
Every finding is tagged to its OWASP API Security Top 10 category.
How ComplyArmor runs API penetration testing
Endpoint discovery through both documentation review and active enumeration — many organizations don't have a complete API inventory — followed by manual exploitation attempts against authorization boundaries, not just automated fuzzing. Delivered as Smart PTaaS — continuous rather than a one-off engagement — and following our testing methodology: discover, scan, exploit, validate. Every finding maps to your compliance requirements.
Frequently asked questions
What is API penetration testing?
Adversarial testing of REST, GraphQL, and SOAP endpoints to confirm whether authentication, authorization, and rate-limiting controls actually hold up against exploitation attempts — not just documentation review.
What is BOLA and why does it matter for APIs?
Broken Object Level Authorization — when an API returns another user's data simply because you changed an ID in the request. It's consistently one of the most common critical findings in API testing because it's invisible without literally testing the exploit.
Do you test undocumented or internal APIs?
Yes. Undocumented and shadow APIs are actively discovered as part of testing, not assumed away — improper inventory management (API9:2023) is one of the OWASP API Top 10 categories specifically because so many organizations don't have a complete picture of their own API surface.
How is API testing different from web application testing?
APIs have no UI to visually inspect, so authorization flaws hide more easily — testing requires directly manipulating requests and tokens rather than clicking through a browser, and focuses heavily on object-level and function-level authorization rather than rendering-layer issues.