Manual, adversarial testing of your REST and GraphQL APIs — authorisation gaps, token abuse and business logic flaws exposed through the interfaces your apps, partners and customers rely on. NCSC CHECK-certified testers.
Book a scoping call See the methodologyAPIs expose your business logic as machine-readable endpoints — easy to consume, easy to abuse. Every authorisation decision your mobile app or partner integration enforces client-side is a suggestion, not a control.
The OWASP API Top 10 ranks broken object-level authorisation first. Changing one identifier in a request is often enough to read another tenant's data.
Deprecated versions, debug endpoints and undocumented routes stay reachable long after the team that built them moved on. Attackers enumerate what you forgot.
A scanner sees valid JSON and moves on. Business logic abuse — mass assignment, excessive data exposure, token replay — needs a human adversary.
As organisations shift to API-first architectures, the flaws that dominate are authorisation flaws — the kind a careful manual test finds first.
Broken object-level authorisation tops the OWASP API Security Top 10 — the single most common API flaw found in the wild.
Source: OWASP API Security Top 10 (2023)Of organisations experienced an API security incident in the past year, per industry survey research.
Source: API security industry surveysOf the OWASP API Top 10 categories are pure authorisation failures — object-level, function-level and sensitive data exposure combined.
Source: OWASP API Security Top 10 (2023)API traffic has grown multiple times faster than web traffic in recent years — and attack traffic on APIs grows with it.
Source: published traffic researchFigures reflect published industry research and frameworks at time of writing; sources cited per card. We're happy to walk through the underlying studies on a scoping call.
API penetration testing is a controlled security assessment in which qualified testers simulate hostile clients against REST, GraphQL and other API endpoints to uncover exploitable weaknesses in authorisation, authentication, token handling, input validation and business logic.
Tests whether users, tenants and integrations can reach objects or functions they should never be able to access.
Examines REST and GraphQL behaviour, token flows, schemas and implementation details rather than treating every endpoint alike.
Looks beyond valid requests to discover how sequences, assumptions and exposed functions can be abused by a hostile client.
Provides reproducible requests, proven impact and concrete remediation guidance your engineering team can act on.
API penetration testing puts a certified human attacker at your interface — enumerating endpoints, abusing token handling, chaining authorisation gaps and business logic flaws into the outcomes that actually hurt: cross-tenant data exposure, privilege escalation, fraudulent transactions.
Our CHECK-certified testers work from the same mindset as a real adversary: map what the API trusts, abuse what it assumes, and prove impact — can one tenant read another's records? Can a revoked token still authenticate? Can a partner integration reach admin functions?
The result is a report written for decisions: every finding with an attack chain, business impact, severity you can defend, and remediation your developers can implement.
As a UK provider working under the NCSC CHECK scheme, our testing is recognised across UK government, financial services and regulated industries — and maps directly to Cyber Essentials Plus, ISO 27001, UK GDPR, DORA and NIS2 obligations.
A scanner validates your schema. A penetration tester reads your API the way a hostile client does — and finds the authorisation gaps no schema check will ever flag.
We test every object-level and function-level check — tenant isolation, role boundaries, admin routes — the way a hostile client would probe them.
NCSC CHECK-certified professionals test your API by hand — with the judgment to spot what a scanner scores as noise but an attacker scores as a way in.
Introspection abuse, query depth attacks, mass assignment and resolver-level authorisation gaps — tested across both modern API styles.
We attack authentication end to end: JWT flaws, refresh token reuse, scope escalation and revocation that doesn't revoke.
Every finding ships with the request, the code-level cause and the concrete fix — written so your team can reproduce, understand and close it without a call.
Fixes often introduce new flaws. We re-verify every remediation against the original attack chains at no extra cost — so your report ends clean, not half-patched.
Every engagement follows the same business-first process — scoped precisely to the systems that matter to your P&L.
Prompt injection, model abuse, RAG data leakage and agent tool misuse — tested before your AI goes live.
ApplicationsAuthentication flows, business logic and the full OWASP Top 10 — attacked the way a real adversary would.
ApplicationsREST and GraphQL endpoints, token handling, and authorisation gaps exposed through the interfaces your partners rely on.
NetworksExternal perimeters, internal networks and Active Directory — from internet-facing foothold to domain compromise.
ApplicationsiOS and Android apps dissected for insecure storage, weak transport and tampering risks on real devices.
NetworksCorporate Wi-Fi, rogue access points and WPA2/WPA3 weaknesses — tested on-site, at your offices.
Six phases, from scoping through to ongoing assurance. Every phase is documented, every finding is actionable.
We inventory your endpoints, authentication flows and environments, agree test windows and credentials, and set the rules of engagement — so testing never collides with your production traffic.
Manual adversarial testing across the OWASP API Top 10 and beyond: object-level authorisation, token and session abuse, mass assignment, injection flaws and excessive data exposure — chained into real attack paths.
Every finding written as an attack chain — the request, the data or privilege reached, the business consequence — with reproduction steps, evidence, OWASP mapping and a fix your developers can act on. Reports land within 5 working days.
We stay with your developers — by call or on-site — reviewing patches, advising on architecture and confirming each fix closes the flaw rather than redirecting it.
We replay the full attack chains, not just the individual findings — because a patched endpoint is worthless if the same flaw survives on a sibling route.
APIs ship weekly. We re-test on your release cadence — every sprint, month or quarter — so new endpoints arrive tested, not untested.
Fixed-fee, CHECK-certified, scoped around your real endpoints. One call is enough to size it.
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