Executive Summary
API security protects application programming interfaces and the data and business capabilities they expose. It combines inventory, strong identity, object and function authorization, input and output controls, resource limits, secure configuration, monitoring, and lifecycle management.
What is API security?
API security protects application programming interfaces and the data and business capabilities they expose. It combines inventory, strong identity, object and function authorization, input and output controls, resource limits, secure configuration, monitoring, and lifecycle management.
APIs are direct routes to business objects and actions, so a valid token is not enough. The service must decide whether this principal may perform this operation on this exact object and fields, in this business state. The OWASP API Security Top 10 provides a useful risk catalog, including broken object authorization, unrestricted resource consumption, sensitive business-flow abuse, server-side request forgery, and inventory problems.
Concrete risks
Risk depends on the deployment, its data, its authority, and the consequences of failure. These scenarios are practical starting points for a system-specific assessment, not a claim that every implementation has the same exposure.
- 01Broken object level authorization can expose or modify another user's record by changing an identifier.
- 02Broken function or property authorization can grant administrative actions or sensitive fields to ordinary users.
- 03Automated abuse can exploit valid purchase, signup, recovery, or reservation flows without malformed requests.
- 04Unrestricted payload, query, processing, or request volume can exhaust services or create unexpected cost.
- 05Forgotten versions, test hosts, and undocumented partner endpoints can remain exposed without current controls.
Security controls
Controls should be layered so one model error, compromised component, or operator mistake does not directly become a material incident. Each control needs an owner and evidence that it works in the deployed configuration.
- 01Maintain an owner, purpose, data class, environment, version, consumer, and retirement state for every API.
- 02Authenticate users and workloads strongly, validate tokens completely, and avoid long-lived shared credentials.
- 03Authorize every object, function, property, and business transition on the server using deny-by-default policy.
- 04Validate schemas, constrain destinations, cap resource use, and apply abuse controls based on business context.
- 05Return only required fields, protect secrets, use transport encryption, and configure errors and cross-origin access safely.
- 06Log security decisions and business outcomes with correlation while excluding tokens and unnecessary sensitive data.
Enterprise application
An enterprise program should combine design standards, reusable gateway and service controls, automated testing, asset discovery, and operational ownership. Gateways improve consistency but cannot understand every object or business rule, so service code remains responsible for fine-grained authorization. Product, fraud, identity, security, and platform teams should share abuse signals. Deprecation must include consumer migration and verified shutdown, not a document label.
Alexa Cybersecurity editorial checklist
The following framework is an original editorial synthesis by the Alexa Cybersecurity Editorial Team. It is intended to help teams structure a review. It is not a standard, certification, benchmark, or field-tested research result, and organizations should adapt it to their systems, obligations, and risk appetite.
- 01Inventory and classify every external, internal, partner, and machine-facing API.
- 02Model objects, functions, properties, workflows, trust boundaries, and likely abuse.
- 03Test authorization with different users, tenants, roles, objects, and lifecycle states.
- 04Constrain input, output, rate, concurrency, payload, query, and downstream destinations.
- 05Protect credentials, dependencies, configuration, and deployment pipelines.
- 06Monitor abuse and maintain revocation, incident, version, and retirement procedures.
Frequently Asked Questions
Q.Does an API gateway solve API security?
A.No. It can centralize authentication, transport, rate, and policy controls, but fine-grained object, property, and business authorization usually requires application context inside the service.
Q.Are internal APIs lower risk?
A.Not inherently. Internal APIs may expose powerful functions, trust broad network locations, and receive less testing. Apply controls according to data and capability, not the internal label.