API Security

API Penetration Testing

APIs power your applications, integrations, and data flows. Our CREST Pathway certified consultants test your APIs directly using bespoke methodologies to uncover authentication flaws, injection vulnerabilities, and data exposure risks.

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Understanding the Risk

What is API Penetration Testing?

APIs are the backbone of modern applications. They connect your mobile apps, web frontends, third-party integrations, and microservices. Every API endpoint is a potential entry point for attackers — and they often expose more data and functionality than intended.

API testing requires a different approach to web app testing. Our consultants interact directly with your API endpoints, testing authentication mechanisms, authorisation controls, rate limiting, input validation, and data handling against frameworks like the OWASP API Security Top 10.

We find the flaws that scanners miss. Broken object-level authorisation, mass assignment, and business logic abuse require manual testing by experienced consultants who understand how APIs are built and how they fail.

The Case for Testing

Why Your APIs Need Penetration Testing

APIs expose more than you think

APIs often return excessive data or expose administrative functions that were never intended for end users. Without testing, these issues go unnoticed until they are exploited.

Authentication flaws are common

Broken authentication, weak token handling, and missing authorisation checks are among the most prevalent API vulnerabilities — and among the most damaging when exploited.

Third-party integrations add risk

Every partner API, webhook, and integration point extends your attack surface. Testing ensures these connections don't introduce vulnerabilities into your environment.

Rapid development outpaces security

APIs are frequently updated and deployed at speed. Regular testing catches the vulnerabilities that slip through fast-moving development cycles.

Compliance frameworks require it

PCI DSS, ISO 27001, and SOC 2 all require security testing of systems that process sensitive data — and your APIs are often the systems doing the processing.

How We Work

Our Testing Approach

OWASP API Security Top 10

We test against the full OWASP API Security Top 10 — covering broken object-level authorisation, broken authentication, excessive data exposure, rate limiting, and more.

Authentication and Token Testing

We probe your API's authentication mechanisms — OAuth flows, JWT handling, API keys, and session tokens — for weaknesses that could allow unauthorised access.

Authorisation and Access Control

We test whether users can access or modify resources belonging to other users, escalate privileges, or bypass role-based restrictions through direct API manipulation.

Input Validation and Injection

We test every input parameter for SQL injection, command injection, SSRF, and other injection attacks that could allow an attacker to read, modify, or delete your data.

Ready to Start?

Get a Fixed-Price API Assessment

Request a free, no-obligation scoping call. We’ll review your API architecture and provide a clear proposal.

Get in Touch

Why Echo Secure

Why Echo Secure?

Industry-certified consultants. UK approved methodologies. Fixed-price proposals with no surprises.

CREST Pathway Certified

Our assessments follow CREST methodologies, the UK gold standard for penetration testing.

Experienced Consultants

Offsec and IASME accredited testers with hands-on experience testing REST, GraphQL, and SOAP APIs.

Clear Reporting

Every finding includes business impact, technical detail, and prioritised remediation steps your team can act on.

Fixed-Price Proposals

No hidden costs. We scope your engagement upfront and provide a fixed price before work begins.

Accreditations