Application Programming Interfaces (APIs) connect systems and serve as the backbone of nearly every digital interaction. They orchestrate services, enable automation, and drive data-driven business processes – their importance in modern IT environments continues to grow rapidly.

But this central role also makes APIs particularly vulnerable. Today, they are among the primary targets of cyberattacks – with risks that are often underestimated. According to a report by Infosecurity Magazine, AI-related API vulnerabilities surged by over 1,200% in 2024, with 99% of those linked to traditional API flaws – regardless of whether AI was involved. The takeaway: APIs have become a critical attack surface across all industries and use cases.

In this context, API security has evolved into a core component of modern IT security architectures. It encompasses all measures designed to protect interfaces from unauthorized access, abuse, and data loss – and is now recognized as a dedicated discipline within the broader field of cybersecurity.

Hidden Risks: Why APIs Are Especially Vulnerable

The biggest API security risks often arise where transparency and control are lacking. Particularly critical are poorly implemented authorization mechanisms – especially Broken Object Level Authorization (BOLA): attackers gain access to data objects they are not authorized to see.

Another major risk lies in so-called shadow APIs. These frequently emerge in agile development environments that use CI/CD pipelines – Continuous Integration and Continuous Deployment – to automatically develop, test, and deploy new features.

While this speed increases efficiency, it also means that not all APIs are properly documented or monitored. As a result, APIs may be high-performing, yet highly vulnerable – especially when they accept unfiltered inputs or expose excessive amounts of data.

Industries in Focus: Where API Attacks Become Critical

The threat landscape varies by industry. In financial services, attackers often target APIs used in payment services or banking platforms – for instance, using credential stuffing or by tampering with transactions.

In healthcare, APIs that handle patient data are frequently exposed – often due to misconfigurations. In e-commerce, insecure APIs can lead to price manipulation, unauthorized purchases, or account takeovers.

B2B platforms are particularly exposed: APIs consumed by partners or third-party vendors often grant access to sensitive backend systems. A single unprotected interface can become the entry point for extensive system compromises.

These scenarios show that API Security is not a niche issue – it is a prerequisite for reliable and trustworthy digital business processes, regardless of the industry or company size.

Beyond Rate Limiting: Rethinking API Security

API Security doesn’t work through isolated tools or quick fixes. What’s needed is a comprehensive security mindset – one that considers architecture, processes, and design equally.

Centralized API management provides the foundation. Only when all production and experimental APIs are documented and managed can governance, monitoring, and testing be implemented effectively. This framework is reinforced by principles such as “least privilege,” ensuring every role has access only to the data and functions it truly requires.

API gateways play a key role here. They manage traffic, handle authentication, and filter potentially harmful inputs in real time. However, it is essential that security requirements are defined in the API specification from the outset – not added later during operations.

Testing and Protection Throughout the Development Process

Many companies underestimate the complexity of API testing. While traditional security scanners perform well for web applications, they quickly reach their limits when it comes to APIs. The reason: APIs behave individually, follow no fixed user interface, and are often deeply embedded in business logic.

To reliably uncover vulnerabilities, specialized fuzzing tools are needed to systematically vary inputs and provoke unexpected system reactions. Yet even these aren’t enough. Manual reviews remain essential – to verify correct implementation of authorization logic or to detect inadvertent data exposure.

API Security only becomes effective when testing is treated as a continuous part of DevSecOps – without compromising time-to-market or agility.

Key Metrics for API Security

Effective IT security depends on visibility. To protect APIs successfully, organizations need clarity – about usage, risks, and weaknesses. Key indicators include:

  • Public API Ratio: How many APIs are publicly accessible – and are they properly documented?
  • Anomaly Detection Rate: How frequently do API requests deviate from expected patterns?
  • Time to Detection (TTD): How quickly are potentially harmful requests identified?
  • Top API Errors: Which types of errors (e.g., 403, 500) occur most often? They may indicate misuse or misconfiguration.
  • API Churn Rate: How often are APIs changed – and are those changes reviewed for security implications?

These metrics enable not only effective monitoring, but also strategic control of API Security initiatives.

API Security Maturity: Where Does Your Organization Stand?

API Security is not a static condition, but a continuous development process. Mature organizations systematically inventory, assess, and optimize their APIs. At the core is a clearly defined governance model with dedicated responsibilities – from API owners to developers to security leads.

Security requirements are embedded in specifications – ideally defined in a way that allows for automated validation and integration into CI/CD pipelines. Regular audits ensure both new and legacy APIs are consistently evaluated against current security standards. Shadow APIs are identified through system-wide discovery processes and documented accordingly.

How we help companies build secure API architecture

We support companies in building secure and efficient API landscapes:

  • By analyzing current APIs, including shadow and legacy interfaces
  • By establishing governance models and robust security architectures
  • Through the integration of modern CIAM, API gateway, and DevSecOps tools
  • And by developing specific security policies for user-centric, high-availability APIs

Our goal: APIs that not only perform, but build trust. We’re here to support you in securing your interfaces and developing a comprehensive security strategy – tailored to your architecture.

Securing APIs Means Strengthening Digital Resilience

APIs are part of the customer experience, data management, and process automation – and thus far more than just interfaces. Failing to secure them systematically not only creates vulnerabilities but also undermines trust in digital services.

With clear processes, modern technologies, and a security-by-design approach, APIs can be designed to be flexible, scalable – and secure. This is where digital resilience begins.