API Spec Generation: Ensuring Consistency and Security

In 2025, AI is the talk of the tech world, but many are forgetting the APIs that power AI behind the scenes. Specifically, security teams are failing to secure these APIs in time as development of AI and other technologies continues at record-breaking speeds.

What is an API specification?

An API specification defines how an API should behave. It contains details about endpoints, methods, request/response parameters and formats, authentication type required, error handling, and more. API specifications act as blueprints for developers.

A typical API specification includes many different components with specific functions:

• API Endpoints- (with URLs and HTTP methods) as well descriptions of what each endpoint does.

• Request Parameters- including query parameters, body parameters, and header parameters.

• Response Structure status codes- such as 415 Unsupported Media Type, 429 Too Many Requests, 500 Internal Server Error.

• Authentication & Authorization- descriptions of how users authenticate with the API  and different access levels or permissions (e.g., admin vs. user roles).

• Rate Limiting & Throttling- details about the limits placed on the APIs.

• Versioning: The version of the API, often in the URL (e.g., `/v1/`), indicating how different versions are handled.

• API Documentation Tools- Some modern APIs include interactive documentation, often generated by tools like Swagger/OpenAPI or Postman, where developers can test the API directly from the documentation.

API specifications ensure consistency, usability, and scalability, enabling developers to integrate with the API smoothly.

The importance of consistency

API specifications essentially make it easier for developers to build APIs and for security teams to audit them and keep them safe. 

Since specifications are similar in functionality for different parts of applications, code can be reused from previously built APIs. New developers joining the team use existing APIs as a reference point for APIs they are building. This reduces the learning curve/ ramp-up time and makes them productive more quickly. For this reason, consistency is key.

The ultimate goal of an API specification is to make it easy for any consumers of your API - from internal users and partners, to external users and stakeholders- to interact with your organization’s APIs. 

The importance of security

Makes it so developers don’t have to solve the problems on their own. If specification defines their controls, and developers don’t have to solve security issues they can focus on application and business logic.

Our research and reports show the problems with APIs are consistently in the application layer. API specs contain the crucial definitions that would have identified calls involved in API breaches as being bad. 

Other traditional security tools don’t handle APIs well and do not prevent API breaches because they are not looking at the correct attack vectors. 

The controls most critical for API security are in the API specification.

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As applications grow, and as AI adoption increases, more APIs will be created and more APIs will be consumed. Having specs that take care of design decisions makes it easier to scale. 

Using an API specification for a zero-trust approach to API security

One other key advantage of an API specification is that it is machine readable. This means that an API specification can be the basis of determining what a “good” API call should look like for that API. A zero-trust (or deterministic) approach to APIs would dictate that any API call that does not match what is defined in the API specification, should not be accepted. This is the principle that the FireTail code libraries are built on.  

Conclusion

API specifications are foundational to API security. They provide comprehensive guides for developers and security teams alike to see how their API endpoints function and communicate. Without them, developers and security professionals would be completely in the dark and vulnerable to a variety of risks to their API ecosystem.

With so many things to think about when it comes to API specifications and security, it can be difficult to stay on top of it all. FireTail can help you identify and track every API across your landscape to build a centralized inventory and audit trail and take control of your cybersecurity. To see how it works, schedule a demo or start a free trial today.