What are Zero Trust APIs?

PUBLISHED ON August 24, 2023
LAST UPDATED Aug 24, 2023

Over the past few years, APIs have become an integral part of virtually every digital platform. Gartner reports that APIs are at the heart of the digital business. According to Slashdata 19th Developer Economics Survey, nearly 90% of developers are using APIs in some capacity. 

Therefore, as the digital landscape continues to evolve, the importance of robust security frameworks becomes increasingly crucial. One of the most critical strategies emerging in this sphere is the zero-trust security framework, which you may have encountered while exploring API security. You might be aware that organizations use this model to protect their APIs from attack. However, what might surprise you is that Zero Trust is one of the best models for API security. As Microsoft reports, 96% of security decision-makers agree that Zero Trust plays a crucial role in their organizational success. So, what does Zero Trust entail? And should your organization consider its adoption? 

What Do Zero Trust APIs Entail? 

Originally developed by the leading technology research company Forrester Research, Zero Trust operates on a fundamental premise of “never trust, always verify” to ensure the utmost security in the digital realm. This means that only users that have been authenticated, authorized, and verified on an ongoing basis can gain access to your network. 

However, with their rising prevalence comes an increased risk. The State of API Security Report Q1 2023, released by Salt Security earlier this year, revealed that 94% of respondents experienced security problems in production APIs over the past year, with 17% having experienced an API-related breach. APIs present unique vulnerabilities, including exposure of sensitive data, unauthorized access, and data leaks, each of which can greatly affect your business. Therefore, the zero-trust framework’s concept of “never trust, always verify” can play a vital role in enhancing API security, providing a solid foundation upon which organizations can build to ensure their digital defenses are as robust as possible. 

Introduction to Zero Trust Security Model 

The zero-trust model operates on the principle that no users or devices should be trusted by default, regardless of their location or network status. In contrast to traditional perimeter-based security models, which assume that everything within the network is safe, the zero-trust model presumes breach and verifies each request as though it originates from an open network. 

The zero-trust security model is based on several core principles: 

  • Least privilege access: Only the minimum necessary access is provided to users, reducing the potential impact of a compromised account.
  • Micro-segmentation: The network is divided into secure zones, each with its own set of security controls. This limits lateral movement within the network.
  • User and device verification: Every user and device is verified before granting access, irrespective of their location or network.
  • Real-time monitoring and analytics: All network activity is constantly monitored and analyzed to identify and respond to suspicious behavior immediately.
  • Automation and orchestration: Security processes are automated wherever possible, improving the response time to security incidents and reducing the likelihood of human error.

This strategy forms the backbone of a zero-trust architecture. This is a comprehensive approach to enterprise cybersecurity that encompasses user identity, device, network, and application and data security. 

Understanding the Need for Zero Trust APIs 

Adopting Zero Trust principles in API security enhances overall security and reshapes data encryption approaches. Unlike traditional applications where data security depends on vendors or service providers, Zero Trust APIs ensure end-to-end encryption of user data, reducing the dependency on service providers. 

The concept of identity verification and real-time trust establishment is key to the zero-trust model. APIs must incorporate a rigorous authentication and authorization mechanism, where each request is authenticated and authorized in real time. This includes validating the identity of users, devices, applications, or services making the API call. Utilizing technologies like token-based authentication (OAuth), multi-factor authentication, and risk-based adaptive authentication can increase the trust level. The zero-trust model also emphasizes “least privilege access” and micro-segmentation. This translates to implementing granular access controls, limiting what each authenticated entity can access. 

When comparing traditional and zero-trust applications, the approach to data safeguarding comes into focus. Traditional applications prioritize protecting, isolating, and monitoring data, often relying on perimeter defenses and trust assumptions. On the other hand, Zero-Trust applications employ a data-centric security approach. This approach implies strong cryptographic controls to encrypt data at rest and in transit and technical designs to allow users to derive value without the need for server-side processing of data. 

When incorporating zero trust into your API design and usage, consider these four areas: 


In the Zero Trust model, all users are considered potential threats. Make sure you identify each user’s authentication and authorization before granting access. Don’t make assumptions about the user’s trustworthiness based on their network location. This process aids in mitigating risks associated with identity theft, insider threats, and compromised credentials. 


Individual API transactions require thorough scrutiny to ensure authenticity. In a Zero Trust model, each API call is treated as a potential security risk. This approach helps ensure unauthorized users or devices are not impersonating legitimate ones to gain access or disrupt operations. Each transaction must authenticate and validate its origin, destination, and the data it carries to ensure security. 


Defining clear parameters around the data shared via each API is crucial. This includes determining how the data is accessed and setting comprehensive policies to safeguard sensitive data both at rest and in motion. Applying strong encryption standards, implementing data loss prevention (DLP) strategies, and using data anonymization techniques can enhance the protection of sensitive data. 


Monitoring and analyzing API transactions and user behavior is key to identifying unusual or anomalous API usage. These could signal a potential attack or attempt to extract sensitive data. By utilizing advanced analytics, AI, and machine learning, you can effectively monitor real-time API activities, identify patterns, detect anomalies, and respond promptly to mitigate potential security threats. 

Implementing Zero Trust Principles in API Architectures 

Below are the steps and best practices for implementing zero-trust principles in API architectures: 

Design Phase 

The journey to a Zero Trust API architecture begins in the design phase. Security should be a core component of API design, not an afterthought. This involves defining clear access policies, implementing granular permissions, and deciding on the encryption techniques to use for data at rest and in transit. The design should ensure no API is accessible without proper authentication and authorization. 

Development Phase 

Rigorous adherence to coding best practices and standards is crucial during the development stage. This can help prevent common security issues, such as injection attacks and cross-site scripting. Regular code reviews and automated testing can help identify potential security flaws early. Furthermore, developers should leverage API security frameworks and libraries that offer built-in functions for authentication, encryption, and other security features. 

Implementation Phase 

When implementing Zero Trust principles, embrace a “deny by default” approach. You should treat every API call as untrusted until verified. This involves validating each API request, scrutinizing its origin, verifying user credentials, and checking the payload for potential threats. 

You can use API gateways to manage, monitor, and secure API traffic. They can provide functionalities like rate limiting, IP filtering, and traffic logging. Additionally, using solutions like OAuth for token-based authentication, OpenID Connect for identity services, and JWT for information exchange can help in implementing strong security controls. 

However, when implementing zero Trust principles in API architecture, you should avoid the following pitfalls: 

  • Inconsistent application of principles: Ensure Zero Trust principles are uniformly applied to all APIs, including internal ones. 
  • Ignoring API dependencies: APIs often rely on other APIs or services. If these are not secure, they can serve as potential entry points for attackers. Therefore, take a holistic view of the entire API ecosystem to ensure comprehensive security. 
  • Static security measures: Cyber threats and attack techniques evolve continuously, and so must your defense strategies. Regularly update security controls to match evolving cyber threats and attack techniques. 

Challenges When Considering Zero Trust APIs 

As you transition towards Zero Trust API architectures, you may encounter some challenges. These range from technical complications to changes in organizational culture. Let’s explore some of them: 

  • Complex client application: The client application is going to be a bit complicated because now the client not only has to send and receive data over the wire, but they also have to implement strong cryptographic controls.  
  • Logistical issues: Developers are typically accustomed to working with APIs and providing authentication tokens. However, they may not be as familiar with implementing strong cryptographic controls. 
  • Security infiltration: There’s always a risk of infiltration attempts by individuals or groups seeking unauthorized access to data. They are going to be creative in finding ways to access it.  
  • Performance overhead: Encryption and decryption introduce a degree of performance overhead. Although modern processors can mitigate this, it can impact performance-intensive applications dealing with big data. 
  • Quantum computing threat: Quantum computing might, in the future, be used to crack encrypted data. While it’s a valid risk, it’s unlikely to be an immediate concern. The developments in quantum computing should also result in developing steps to counteract it using quantum encryption. 
  • Scalability: Scaling up Zero Trust APIs without affecting performance can be a challenging task. 
  • Organizational Change: A shift to Zero Trust involves a cultural shift in how security is viewed and implemented, requiring a comprehensive awareness and training program for staff. 

How Can ThreatX Provide an Additional Layer of Security? 

ThreatX provides API protection solutions that just work. We help businesses protect sensitive data in an end-to-end manner. ThreatX helps facilitate the seamless integration of Zero Trust principles into your API infrastructure, ensuring your data remains secure whether at rest or in transit. We have security professionals on call 24/7 to help with configuration and threat hunting, among other functions key in securing APIs. 

About the Author

Neil DuPaul

Neil DuPaul is the Sr. Director of Demand Generation at ThreatX and works with the team to execute impactful, customer-centric campaigns. He has 15+ years marketing a variety of cybersecurity solutions, executing a range of tactics and strategies across many business functions. A lifelong learner and gamer with a zest for physical activity.