What API security testing covers
We test every layer of your API — not just authentication, but the authorization decisions made on every single request.
Object-level authorization
Can user A access user B's transactions, account details, or payment history by manipulating IDs? This is the most common and most dangerous API vulnerability in fintech products.
Function-level authorization
Can a regular user call admin endpoints? Can a merchant trigger refunds beyond their limit? We test every role against every endpoint.
Data exposure
APIs that return more data than the client needs — full account numbers, BVN fragments, internal IDs, or PII in error messages. We catalogue every instance of unnecessary exposure.
Rate limiting & abuse
OTP brute-force, credential stuffing, enumeration attacks. We verify that sensitive endpoints have effective rate limits that can't be bypassed with header manipulation or IP rotation.
Webhook & callback security
Payment confirmation webhooks that can be spoofed, callback URLs that accept unsigned payloads, and event handlers that don't validate source authenticity.
Integration boundaries
The handoffs between your backend and third-party services — payment processors, KYC providers, banking APIs. Where secrets are stored, how failures are handled, and what happens when the upstream lies.
Privilege escalation through stale tokens
Refresh tokens outlived logout. Admin actions checked permissions at login, not at execution. Expired sessions still carried full authority. Fix priority: this sprint.
API testing methodology
We don't just run an API scanner against your Swagger docs. Our testing follows actual product logic — the same paths a sophisticated attacker would take.
API surface mapping
We map every endpoint — documented and undocumented. We check for debug endpoints, legacy versions, and internal APIs exposed through client-side code.
Authorization matrix testing
Every endpoint tested against every role. We build a matrix of who should access what, then systematically verify that boundaries hold.
Business logic exploitation
We chain API calls in sequences that break business rules — transferring negative amounts, replaying idempotency keys, racing concurrent requests to bypass balance checks.
Find out what your API is actually exposing.
Get a Quick Security CheckFrequently asked questions
Do you test both REST and GraphQL APIs?
Yes. We test REST, GraphQL, gRPC, and WebSocket interfaces. Fintech products increasingly mix protocols — the gaps between them are often where authorization breaks down.
What about third-party API integrations?
We review how your application talks to payment processors, identity providers, and banking APIs. Specifically: how secrets are stored, how webhook payloads are validated, and what happens when upstream services return unexpected responses.
Can you test APIs that require authentication?
Yes. We test with authenticated sessions across multiple privilege levels — regular users, merchants, admins, and API key holders. Horizontal and vertical privilege escalation testing is standard.
How do you handle rate limiting testing?
Carefully. We test rate limit effectiveness on sensitive endpoints (login, OTP verification, password reset) without flooding your infrastructure. We validate that limits exist and can't be trivially bypassed.