Web Application & API Security Testing Services

Web application and API security testing examines your website, web app, and the APIs behind it for vulnerabilities like broken authentication, injection flaws, and business-logic errors — the issues most commonly exploited to steal data or take over accounts. This goes well beyond a basic vulnerability scan: it tests how your application actually behaves under attack, including flaws that only appear when someone deliberately misuses the application’s intended functionality. PS INFOSEC combines automated scanning with manual, human-led testing to find what tools alone consistently miss.

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What Is Web Application & API Security Testing?

Modern applications are rarely just a website — they’re a website (or mobile app) talking to one or more APIs, which in turn talk to databases and third-party services. Each layer introduces its own risk: the frontend can have client-side vulnerabilities, the API can leak data through broken authorization, and the business logic connecting them can be manipulated in ways no automated scanner is designed to catch.

Testing follows the OWASP Top 10 — the industry-standard reference for the most critical web application security risks, including injection, broken authentication, and security misconfiguration — as a baseline, then goes deeper into business-logic and authorization testing specific to how your application actually works.

What We Test

Web Application Penetration Testing

Full OWASP Top 10 coverage across your website or web application

API Security Testing

REST and GraphQL API testing for authentication, authorization, and data exposure issues

Authentication & Authorization Review

Broken access control, session management, and privilege escalation testing

Business Logic Testing

Manually testing how the application's actual workflows can be manipulated — flaws automated scanners structurally cannot detect

Secure Source Code Review

SAST-assisted scanning combined with manual code review for deeper, white-box-level assurance

Secure Configuration Review

Server, framework, and deployment configuration review for security misconfigurations

Our Testing Process

Why Business Logic Testing Matters

Automated scanners are good at finding known vulnerability signatures — but they don’t understand what your application is supposed to do, so they can’t tell when that logic is being abused. A checkout flow that can be manipulated to apply a discount twice, or an API that returns another user’s data if you change one number in the request, are both examples of vulnerabilities that require a human tester who understands the application’s intended behavior well enough to find a way to break it.

This is the core of what manual testing adds beyond automated scanning, and it’s where most of the serious, exploitable vulnerabilities in real-world applications are actually found.

What You Get: Deliverables

Technical Findings Report

Every vulnerability with proof-of-concept evidence and CVSS-based severity scoring

Business Logic Findings

Documented separately, since these require narrative explanation beyond a standard CVSS entry

API Test Coverage Summary

Which endpoints were tested and what was found, endpoint by endpoint

Remediation Roadmap

Prioritized, developer-actionable fix guidance

Free Retest

Verification that fixes are genuinely effective

Industries We Serve

We’ve delivered engagements across a range of sectors, including:

Banking & Financial Services
Healthcare & Life Sciences
Information Technology & SaaS
Manufacturing
Government & Public Sector
Retail & E-Commerce
Education
Telecommunications
Logistics & Transportation
Professional Services

Frequently Asked Questions

What is OWASP Top 10 testing?

The OWASP Top 10 is the industry-standard list of the most critical web application security risks — including injection, broken authentication, and security misconfiguration. Testing against it is considered the baseline standard for web application security testing.

Do you test mobile app APIs too?

Yes — API testing here covers APIs consumed by both web and mobile applications. Mobile app-specific testing, like local storage and binary analysis, is covered separately under our Mobile Application Security Testing service.

What's the difference between API testing and web app testing?

Web application testing covers the full user-facing application, including client-side behavior. API testing focuses specifically on the backend endpoints your application (or mobile app, or third parties) calls — APIs are frequently more exposed and less protected than the interface built on top of them, so they warrant dedicated testing.

Can you review our source code as well as test the running application?

Yes — secure source code review is available as part of this service, combining automated SAST tooling with manual review for deeper assurance than black-box testing alone provides.

What is business logic testing and why does it matter?

Business logic testing manually examines how your application's actual workflows can be manipulated — for example, whether a multi-step process can be reordered or repeated to produce an unintended result. These flaws are invisible to automated scanners because they require understanding what the application is supposed to do before you can find a way to misuse it.