The digital age has brought the power of API (Application Programming Interface) to the forefront, enabling seamless communication between software applications. However, the importance of API security cannot be overstated. With the increasing reliance on APIs, safeguarding sensitive data and ensuring the proper functioning of applications has become crucial. In this blog post, we will take you on a journey to understand the essentials of what is API security, from its types and common threats to best practices and tools. Let’s embark on this quest to fortify our APIs and protect our digital assets.

Key Takeaways

  • With application programming interfaces growing in popularity, security teams can’t keep up, making them a prime target for attackers.
  • Not all APIs are created equally, and we’ll explore some common vulnerabilities that malicious actors can target, including insecure communications, broken access control, and injection attacks.
  • In this day and age, developers must implement the best practices to secure their API calls. These best practices include constant monitoring and logging, implementing encryption services, and adopting secure coding practices.
  • API protection is now more important than ever as malicious automation can launch attacks at scale.
  • Kasada’s API protection is designed to stand out from our competitors by using a novel approach, including dynamic detection that ensures data integrity collected by invisible sensors. The use cases for our software are enormous, as are its potential benefits.

What Are Application Programming Interfaces?

A group of people ensuring API security by working on computers in an office.

An application programming interface, or API, is a set of guidelines and protocols for building software applications. It acts as a layer of communication between different software components, allowing them to interact with each other in a standardized and predictable way.

Importantly, APIs provide developers with a way to access the functionality of an existing software application or service without knowing the details of its implementation. This makes it easier to build applications that rely on external services or data sources, as developers can simply call the appropriate API functions to retrieve the information they need.

Practically, APIs can be used for a wide range of purposes, from enabling communication between different software components within a single application to providing access to third-party services such as social media platforms or payment gateways. They are often documented and made available publicly so other developers can use them to build new applications or integrate existing ones with external services.

APIs have been heralded as a more efficient way to build web applications in contrast to more traditional methods, and research certainly backs this claim up. A recent study showed that public firms that adopted APIs experienced a 12.9% increase in their market value versus their non-adopting competitors. Over 16 years, this figure rose to 38.7%.

Understanding API Security

API security plays a pivotal role in safeguarding sensitive data and guaranteeing applications run smoothly. Without robust security measures, vulnerabilities such as signature-based attacks, weak rules for JSON paths and schemas, and the absence of rate limits can wreak havoc on API security. To maintain the integrity and confidentiality of data transferred through APIs, it is imperative to implement secure authentication and authorization mechanisms, as well as encrypt API requests and responses.

API calls, synonymous with requests to api endpoints, form the backbone of communication between an API and any other system. APIs expose application logic, which can create vulnerabilities if not properly secured. Inadequate API security can lead to unauthorized access, data breaches, and other malicious activities. Grasping the importance of API security and applying best practices allows us to counter these threats and contribute to a safer digital landscape.

Why API Security Matters

API security is of paramount importance due to the exposure of application logic, resources, and sensitive data, making them a prime target for attackers. Inadequate security measures can lead to unauthorized access, data breaches, and service disruptions, consequently affecting customer trust, regulatory compliance, and even causing financial losses. Real-world examples of API security breaches, such as LinkedIn in June 2021, Venmo, Facebook, USPS, Brazil’s FIESP, and JustDial, along with the First American Financial Corp. data leak in 2019, emphasize the potential consequences of not securing APIs properly.

Comprehending the importance of API security and adopting best practices empowers us to safeguard our digital assets and reduce breach risks, making API security important.

Types of APIs: SOAP, REST, and GraphQL

In the realm of APIs, there are three primary types: SOAP, REST, and GraphQL. Each type has its own unique security considerations due to their distinct architectural styles and data transfer methods. SOAP APIs use XML and adhere to Web Services (WS) specifications, providing built-in security features.

On the other hand, RESTful APIs rely on JSON data transfer and HTTP/S protocols, with security depending on proper API design, transport layer security, and token-based authentication.

Lastly, GraphQL is a query language that allows clients to request specific data, posing security risks due to customizable requests and requiring mitigation strategies such as throttling and setting maximum query depths. Recognizing the unique security challenges and requirements of each API type enables us to devise bespoke security measures for more effective API protection.

SOAP API Security

SOAP is a protocol for exchanging structured data. It is specified by the World Wide Web Consortium for implementing web services in computer networks. SOAP APIs adhere to the Web Services (WS) specifications, providing built-in security features such as WS-Security, encryption and digital signatures, and authentication mechanisms. APIs rely on transport layer security (e.g. HTTPS) and message-level security (e.g. XML digital signatures and encryption) to protect data. These measures are typically employed in combination for maximum security..

Making use of SOAP’s inherent security features, developers can set up more secure communication channels and shield their APIs from potential threats.

REST API Security

REST (Representational State Transfer) APIs are designed with simplicity and flexibility in mind, using JSON data transfer and HTTP/S transfer protocol. Unlike SOAP APIs, RESTful APIs do not have built-in security features and must be safeguarded through implementation and architectural decisions. Ensuring proper API design, transport layer security, and token-based authentication is crucial for the protection of RESTful APIs.

TLS, for example, is employed in REST APIs to encrypt the communication and safeguard the data in transit, ensuring that the information sent and received is shielded from unauthorized access. Putting these security measures into practice and sticking to best practices allows developers to construct a safe environment for RESTful APIs.

GraphQL API Security

GraphQL is a query language that offers flexibility, granularity, and complexity when compared to REST and SOAP API security. Clients can request only the specific data they need with GraphQL, reducing the risk of overexposure. However, GraphQL’s customizable requests also present security risks. One such risk is deep query nesting, which can generate complex and resource-intensive queries, resulting in denial-of-service attacks or excessive server load.

API providers can counter these threats by enacting throttling and setting maximum query depths, which guarantees efficient and secure execution of GraphQL queries without compromising its flexible and granular advantages.

API Attacks

multi-color code on laptop screen

But as the popularity of APIs and their use cases have exploded, so too did the need to tighten their security. Security resources simply can’t keep up with the massive increase in API usage, meaning, the more APIs a company uses, the more potential vulnerabilities exist.

API gateways play a crucial role in preventing API breaches by acting as a mediator between clients and APIs.

An API gateway provides a single point of entry for all API requests and enforces security policies such as authentication, authorization, and rate limiting. This helps to prevent unauthorized access to APIs and reduces the risk of API breaches.

The Rise of API Breaches

It’s no surprise that with the prolific adoption of APIs, there has also been a significant increase in the number of attacks. In the past few years, more companies than ever have found themselves in the headlines as victims of noteworthy hacks, including Facebook, Google, T-Mobile, and Venmo.

In these real-life situations, the far-reaching consequences of API attacks can devastate companies and victims.

Besides the legal aftermaths, the financial ramifications of API breaches can also be crushing. When Australian telecommunications company Optus was hacked last year, the attackers demanded a $1 million cryptocurrency payout, or else they would sell the API data.

Globally, it’s estimated that API insecurity costs businesses between $41 to $75 billion annually and between $12 to $23 billion in the US alone.

API security threats come in various forms, with the most frequent including the OWASP API Top 10 and business logic attacks. The OWASP API Top 10 is a list of the top 10 API security risks published by the Open Web Application Security Project (OWASP) in 2019, providing guidance on how to protect against these vulnerabilities.

Business logic attacks, on the other hand, exploit the business logic of an API, such as bypassing authentication or authorization checks, or manipulating data in a manner not intended by the API. Recognizing and tackling these common threats enables us to boost our API security and shield our applications and data from potential breaches.


The OWASP API Top 10 is a valuable resource for identifying and addressing the most critical security risks affecting APIs. The list includes excessive data exposure, broken API authentication, insecure direct object references (IDORs), security misconfiguration, sensitive data exposure, and others.

Excessive data exposure, for instance, occurs when developers fail to itemize restrictions for object properties, resulting in the client not filtering out unnecessary data before it is displayed in the UI, potentially providing attackers with access to sensitive data. Comprehending the risks in the OWASP API Top 10 and applying suitable security measures lets us guard our APIs against widespread threats and foster a safer digital environment.

Business Logic Attacks

Business logic attacks target the underlying logic and functionality of an API, often bypassing traditional security measures and leading to unauthorized access or data exposure. These attacks manipulate the expected behavior of the API, allowing attackers to:

  • Bypass security measures such as firewalls, intrusion detection systems, and encryption
  • Gain unauthorized access to sensitive data
  • Modify or delete data
  • Perform actions that are not intended or allowed by the API’s logic

It is important for developers to be aware of these types of attacks and implement proper security measures to protect their APIs.

Examples of business logic attacks on APIs include data breaches, APIs relying too heavily on client-side controls, and APIs making flawed assumptions about the input they receive. Countering business logic attacks in API security necessitates the implementation of suitable validation and security measures, guaranteeing the preservation and security of our APIs.

The Role Bots Play in API Attacks

Like any use of malicious automation during any type of attack, bots are leveraged for their blend of ease of use, sophistication, and cost effectiveness. Bots allow adversaries to launch API attacks at scale. Carrying out malicious actions far faster than a human could. If APIs are not protected against automation it leaves them vulnerable to attackers’ favorite tool.

API Security Best Practices

A laptop computer with a green screen on it, demonstrating API Security.

Securing APIs requires a combination of best practices, including:

  • Authentication and authorization
  • Data classification
  • Encryption
  • Continuous monitoring

These practices help protect sensitive data, maintain the proper functioning of applications, and ensure compliance with relevant regulations.

Adhering to API security best practices allows us to reduce the possibility of unauthorized access, data breaches, and other security incidents, thereby fostering a safer digital landscape for our applications and users.

Authentication and Authorization

Strong authentication and authorization methods are crucial for ensuring only authorized users can access protected resources within APIs. OAuth is a token-based authentication framework. It allows third-party services to access user information without having to disclose the credentials.

Multi-factor authentication (MFA) adds an additional layer of protection by requiring users to provide multiple forms of identification in order to access a system or application. Deploying strong authentication and authorization measures strengthens API security and shields our digital assets from unwanted access.

Data Classification and Exposure

Limiting data exposure is essential for maintaining API security. By implementing data classification and server-side filtering, we can ensure only necessary information is accessible to authorized users. Data classification involves categorizing and labeling data based on its sensitivity and importance, allowing organizations to apply appropriate security measures and access controls to protect the classified data.

Server-side filtering, on the other hand, validates and filters user input on the server side to guarantee only pertinent and secure data is delivered to the client. These techniques help to prevent unauthorized access, data breaches, and ensure compliance with data protection regulations.

Encryption and Secure Communication

Encryption protocols like HTTPS and SSL/TLS are crucial for protecting the confidentiality and integrity of API traffic. HTTPS provides a secure connection for API traffic by encrypting the data exchanged between the client and the server. SSL/TLS, on the other hand, is a cryptographic protocol that provides secure communication over the internet, ensuring that unauthorized parties cannot read or modify the transmitted data.

Utilizing encryption and secure communication protocols enables us to defend our APIs against possible threats and secure sensitive data during transmission.

Continuous Monitoring and Security Assessments

Regular monitoring and assessment of API security are crucial for identifying and addressing potential vulnerabilities and maintaining compliance. Continuous monitoring involves the ongoing and automated process of monitoring the availability, performance, and security of APIs, promptly identifying and addressing any potential threats or risks.

Security assessments, on the other hand, involve a thorough examination of the security measures implemented for an API to detect any vulnerabilities, risks, and weaknesses. Performing regular API security assessments and executing continuous monitoring enhances our API security, thereby protecting our applications and data from potential breaches.

API Security Tools and Solutions

Various tools and solutions are available to help secure APIs, including API gateways and open-source testing tools. These API security tools and solutions offer features such as request builders, response visualizations, and api security testing to optimize API testing and security.

Selecting API security tools and solutions necessitates consideration of the following aspects:

  • API styles support
  • Authentication and authorization capabilities
  • Access control mechanisms
  • Encryption support
  • Data validation features
  • Documentation and specifications support
  • Scalability
  • Usability
  • Vendor support and reputation
  • Cost

API Gateways

API gateways play a critical role in API security by acting as a reverse proxy, authenticating traffic, and providing a layer of security between client and backend services. An API gateway offers access management, enforces policy, monitors and protects traffic, simplifies security configuration, and logs and analyzes data to bolster the security of APIs.

Additionally, API gateways can assist with load balancing and request routing, ensuring optimal performance and scalability for APIs.

Open Source API Testing Tools

Open-source tools that can greatly benefit API security include:

  • Postman: An API client used for testing, offering features such as request builders, response visualizations, and test automation.
  • Swagger: Facilitates API security by enabling the description of security schemes and authentication mechanisms.
  • JMeter: A load testing tool that can also be used for API testing.

Utilizing these tools can help improve your web API security.

These open-source tools provide an accessible and cost-effective solution for ensuring the security of APIs throughout their lifecycle.

How Kasada Can Protect Your APIs

Safeguarding APIs from malicious automation is an important first step in defending APIs. Kasada’s API protection aims to counter the mindset of attackers, by removing the financial reward of an attack. Bot operators leverage bots because they offer the best ROI when conducting an attack at scale. By making bot attacks too expensive to conduct through the use of constantly changing detection logic and highly obfuscated defenses. This combination makes reverse engineering attempts too costly and time consuming eliminating the ROI of the attack. Kasada’s dynamic nature means that even if an attacker successfully creates a work around to our defenses, that bypass is rendered useless in minutes, unlike other anti-bot providers which are static and take months to roll out defense updates.

Kasada Bot Management

API Security Best Practices - Kasada

Kasada’s bot management solution combines bot detection and API security to differentiate bots from human users, mitigating the risk of automated fraud and data breaches. Kasada Bot Management employs various techniques to detect the immutable presence of automation, including invisible signal collection, data integrity checks, client validation, anomaly detection, and rapid feedback from a 1 trillion data points ingested weekly.

By providing web, mobile and API protection designed to last and surpass traditional bot management solutions, Kasada aids businesses in combating the threat of bots and diminishing the risk of automated fraud.


In conclusion, API security is a critical aspect of safeguarding our digital assets and ensuring the proper functioning of applications. By understanding the types of APIs, common security threats, and best practices, we can effectively protect our APIs from potential breaches and unauthorized access. Utilizing tools and solutions like API gateways and open-source testing tools, as well as partnering with dedicated API security providers like Kasada, we can ensure continuous protection and maintain a secure API environment. With a proactive approach to API security, we can confidently build and deploy applications that stand strong against the evolving threats of the digital landscape. Contact Kasada today to get started.

Frequently Asked Questions

What is meant by API security?

API security is the practice of protecting an application programming interface (API) from malicious attacks and vulnerabilities, to ensure the secure transfer of sensitive data.

What is an example of API security?

API security is an important measure to protect against common web-based attacks such as SQL injection, XSS, and CSRF.

What are the types of API security?

API Security consists of three main authentication methods, namely HTTP Basic Authentication, API Key Authentication and OAuth Authentication. Additionally, a fourth method of no authentication can also be utilized.

Why use API security?

API security is essential for protecting sensitive data transmitted by APIs, such as authentication, authorization and encryption. Ensuring your API is secured helps maintain data confidentiality and integrity.

What is the difference between authentication and authorization in API security?

Authentication is the process of verifying a user’s identity, while authorization verifies that the user has the correct permissions to access a given resource.

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