API Security: Authentication vs Authorization
APIs make data and functions available to a range of different users and clients. However, with the constantly evolving API threat landscape, providing this access comes with significant risk. A report published in February 2025 found that almost every organization (99%) experienced an API security issue in the past year.
To deploy APIs while maintaining security, you must ensure access is only available on your terms. That is where API authentication (authN) and authorization (authZ) come in, proving clients are who they say they are and choosing what they have access to. Understanding authentication vs authorization in API Security, and the best practices for implementing each, is a massive step towards staying ahead of the latest threats.
What is Authentication?
API authentication verifies the identity behind an API request, checking credentials to ensure the user, service, or system is who they claim to be. Authentication is the first line of defense for APIs, only allowing legitimate actors to interact with them and preventing attackers from gaining unauthorized access to API data and functionality.
The process of API Authentication typically involves:
- Credential Presentation: The client presents their credentials that prove their identity
- Credential Validation: The API or gateway checks if the credentials are valid
- Session Establishment: An API session starts by assigning a unique, temporary identifier to the user in order to prevent authenticating credentials with every request. Stateless APIs, such as Representational State Transfer (REST), perform identification with every API call
There are a number of different API authentication methods. Each offers distinct pros and cons and is suitable for different situations. Understanding the different API authentication models is critical to optimizing the security for your specific use case.
The most common methods are:
Basic Authentication
A simple API authorization model that encodes a username and password in the request. Basic authentication is lightweight and easy to implement; the credentials can be input in the HTTP header as a Base64 string.
However, it offers less protection compared to more advanced methods. Base64 is encoded, not encrypted, meaning basic authentication on its own is inherently insecure. It has to be used over HTTPS to provide encryption, and ideally, it should be used with short-lived credentials. Without HTTPS, the username and password can be easily intercepted and decoded. Basic authentication is also susceptible to brute force password attacks and users choosing weak passwords.
Generally, you should only use basic authentication in controlled internal networks, not for externally accessible APIs.
OAuth Authentication
OAuth authentication is an industry-standard open framework that has become a widely used method for modern APIs using token-based authentication. The original OAuth 1.0 framework was replaced by OAuth 2.0 in 2012. Users input their login credentials and are provided with a token that allows access to the API.
This offers greater security than basic authentication with an encrypted token sent with each call rather than a username and password. OAuth authentication also improves the user experience with Single Sign-On (SSO) capabilities, as credentials can be leveraged from one service provider to log into another service provider. Think of logging into a service through your Google account.
Additionally, when it comes to authentication vs authorization in API Security, organizations can use OAuth for both. The same token can determine what the user has access to as well as prove their identity. However, security incidents are possible if attackers steal tokens and gain unauthorized access. OAuth authentication is also more complicated to implement than basic authentication.
API Keys
A simple, unique identifier issued by the API developer that must be included in each request header. API keys are an easy-to-implement solution for access control that offers greater security than basic authentication, assuming it is encrypted and sent over HTTPS, but less protection than token methods like OAuth authentication.
A key factor in understanding API keys is that they are tied to the application, not the user. This does mean multiple users can use the same API key and gain access. Additionally, it is simple to include API keys in scripts that enable programmatic access.
JWT (JSON Web Tokens)
A JWT is a self-contained token containing identity claims. This form of token is commonly used in stateless APIs for performance and scalability. Signed or encrypted, JWTs include information on the user’s identity that provides API access. As a token-based authentication method, JWTs offer greater security compared to basic authentication or API keys, and they are often used with OAuth 2.0.
What is Authorization?
In terms of API authentication vs authorization, while authentication determines who they are, authorization determines what they have access to. Performed after authentication, API authorization models typically use tokens provided to the client to determine the specific resources they have access to.
A standard method of how an API authorization model works is:
- Identity Context: Authorization decisions rely on the identity established via authentication
- Policy Evaluation: The system checks predefined rules to decide if the request is allowed
- Access Enforcement: The API enforces the decision, granting or denying the request
There are several ways to implement API authorization models. Popular examples include:
Scope-Based Authorization
Widely used in OAuth authentication, scope-based authorization limits API access by defining permissions or scopes for an access token. In OAuth 2.0, tokens provide both authn and authz. The client app separates API authentication vs authorization, requesting specific scopes, and the API grants or denies them. This API authorization model enables secure, delegated access, making it ideal for securing APIs with authN authZ in partner integrations.
Role-Based Access Control (RBAC)
RBAC API models assign permissions based on predefined roles such as admin, editor, or viewer. This simplifies management and enables APIs to enforce the principle of least privilege. By clearly defining roles and limiting access to what’s necessary, RBAC helps reduce security risks. While straightforward to implement, it can be less flexible in complex environments and requires you to review each user’s role periodically.
Attribute-Based Access Control (ABAC)
ABAC API models offer a more dynamic alternative to RBAC APIs by granting or denying access based on attributes of the user, resource, and environment. Policies can factor in contextual information like user department, resource classification, or request time. This approach supports fine-grained access control for complex scenarios, especially when combined with RBAC. While powerful, ABAC’s complexity requires careful design to avoid misconfigurations that could weaken API auth best practices.
Policy-Based Access Control (PBAC)
PBAC enforces centralized rules that determine access rights, often blending RBAC and ABAC for improved flexibility. Policies can be dynamic, adjusting access in real-time based on changing attributes or environmental conditions. This makes PBAC especially valuable for securing APIs with complex authN authZ requirements in cloud and enterprise contexts.
Authentication vs. Authorization in API Security: Key Differences
While both processes are essential, they serve separate purposes. Authentication confirms the identity of a user or service, while authorization determines what that authenticated actor can access. Understanding these differences is critical for API auth best practices, from OAuth authentication flows to RBAC API and ABAC API models.
The table below highlights the key differences in how each function operates while securing APIs with authN authZ strategies.
| Authentication(AuthN) | Authorization (AuthZ) | |
| Definition | The process of verifying the identity of a user, application, or system | The process of determining what actions or resources an authenticated entity is allowed to access |
| Goal | Ensure the user, application, or system is who it claims to be | Ensure they can only perform approved actions |
| When It Happens | Before authorization | After successful authentication. |
| Inputs | Credentials (username/password, API key, token, certificate) | Roles, scopes, attributes, policies, and contextual rules |
| Common Methods | API keys, Basic Auth, OAuth tokens, JWTs, etc | RBAC API, ABAC API, scope-based rules, etc |
| Output | Authenticated identity | Access decision (permit, deny, limit) |
| Where It’s Enforced | Usually at the API gateway or authentication server | At the API gateway, resource server, or application logic layer |
| Consequences if Compromised | Attackers can impersonate a valid user or service | Attackers can escalate privileges or access unauthorized data |
Why Are API Authentication and Authorization Important?
Both functions are critical for securing sensitive data and preventing misuse of API resources. Authentication ensures that only verified users or applications can access an API, while authorization enforces what those authenticated entities are allowed to do.
Robust authN vs authZ API controls ensure approved users take approved actions when interacting with your APIs.
With access to sensitive business data and functions, hackers are increasingly targeting APIs using a variety of techniques to exploit weak authN authZ strategies. If successful, these attacks can lead to data breaches, account takeover, and privilege escalation, resulting in a major security incident. Additionally, you have to consider regulatory consequences if poor authN authZ strategies lead to non-compliance.
In contrast, robust API auth best practices deliver significant security and operational benefits in terms of:
- Data security: Only authorized clients can retrieve or modify sensitive resources
- User privacy: Enforces user consent before data is accessed or shared
- Resource protection: Prevents misuse, overuse, or abuse of API endpoints.
Best Practices for Proper Authentication
Key API auth best practices to implement include:
- Always use HTTPS to encrypt credentials and tokens
- Utilize token-based authentication (OAuth, JWT) over static API keys for public APIs
- Regularly rotate API keys and tokens
- Short-lived tokens reduce replay attack risk
- Implement multi-factor authentication (MFA) where applicable
- Validate tokens server-side for every request
- Utilizing an API gateway can help deliver centralized, uniform authentication
6 Tips for Better Authorization
Listed below are 6 tips to improve your API authorization models:
- Implement least privilege access and grant only necessary permissions
- Use RBAC or ABAC APIs based on complexity and flexibility needs
- Centralize authorization logic to avoid inconsistencies
- Audit and log authorization decisions for compliance and debugging
- Regularly review unused roles and permissions
- Combine authorization checks at both the API gateway and application level
API Security with CloudGuard WAF
Organizations must renew their focus on API security, given the evolving threat landscape. Any APIs you develop or use must have robust authentication and authorization mechanisms to ensure the security and safety of you and your clients.
API security is much easier when you have the right tools in place. Check Point’s best-in-class Web Application Firewall, CloudGuard WAF, offers prevention-first, automated application and API security. This includes enforcing the API schema to stop malicious API access.
Get in touch with one of our experts today and learn how this cloud-native solution can be deployed within minutes to take your API security to the next level.
