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API penetration testing.

Your mobile app and your single-page front end are just API clients. The API is the real target, and it is usually tested least. We test REST, GraphQL and the authorisation logic underneath both.

At a glance

Typical duration
1 to 2 weeks plus reporting
Approach
Authenticated, multi-role, specification-led
Standards
OWASP API Security Top 10
Formats
REST, GraphQL, gRPC on request
Retest
Included
01Overview

What we look for.

Object-level authorisation is the most common serious API flaw and the hardest to find automatically, because a scanner cannot know that order 1041 belongs to a different customer than order 1042. We test with multiple accounts across multiple roles specifically to prove where that boundary fails.

02Coverage

What we test.

Broken object-level authorisationCross-account and cross-tenant access by identifier manipulation, the flaw class that produces the largest breaches.
Broken authenticationToken forgery, algorithm confusion, weak signing keys, expiry and revocation handling, refresh-token abuse.
Excessive data exposureEndpoints returning more than the client renders, internal fields leaked in responses, verbose error objects.
Mass assignmentPrivilege fields writable through object binding, role escalation via unexpected parameters.
Function-level authorisationAdministrative endpoints reachable by standard users, undocumented methods on documented routes.
Rate limiting and resource abuseEnumeration, credential stuffing surface, expensive queries, unbounded pagination and payload sizes.
GraphQL specificsIntrospection exposure, query depth and complexity abuse, batching attacks, field-level authorisation gaps.
Shadow and undocumented surfaceEndpoints absent from the specification, deprecated versions still routable, staging hosts reachable from production.
03Deliverables

What you receive.

01Executive summary

Risk posture in plain language for leadership and the board, with the two or three things that actually matter.

02Technical findings

Severity, proof-of-concept evidence, reproduction steps and specific remediation, written for the engineer who has to fix it.

03Compliance annex

Findings mapped to SOC 2, ISO 27001, PCI DSS and HIPAA controls so your auditor can use the report directly.

04Attestation letter

A shareable letter confirming scope, dates and outcome, reissued free after we verify your fixes.

04Fit

Who needs this.

  • Platforms where partners or customers integrate directly against your API
  • Mobile-first products where the API carries all business logic
  • Anyone who has added endpoints faster than they have documented them
  • Fintech, healthcare and marketplace products with multi-tenant data
  • Teams preparing for a customer security review or SOC 2
05Questions

Frequently asked.

Do you need our API specification?

It helps and it speeds things up, but we do not rely on it. We proxy real client traffic and enumerate independently, because the endpoints missing from your specification are frequently the interesting ones.

Can you test a GraphQL API?

Yes. GraphQL shifts the risk rather than removing it: introspection, query depth and complexity, batching and per-field authorisation all get tested explicitly.

How many roles should we provide?

At minimum two accounts at the same privilege level plus one of each elevated role. Two same-level accounts are what let us prove cross-tenant access rather than describe it as theoretical.

Is this included in a web application test?

Some overlap is unavoidable, but a dedicated API engagement goes considerably deeper on authorisation and enumeration. If budget forces a choice and your logic lives in the API, test the API.

Ready to find out what an attacker would find?

Tell us about your environment and we will come back with a scoped quote and a start date. No discovery-call marathon, no obligation.