API Security Best Practices: Stop Breaches Before They Start

With 83 percent of organizations finding API integration critical to their business strategy, APIs are one of the most integral parts of virtually any web application today, enabling organizations to scale more quickly than ever before.

But this comes with a price.

91 percent of developers say APIs are their company's biggest security risk - in fact, the latest IMB report attributes two-thirds of cloud breaches to API flaws. If not properly secured, hackers can exploit them to gain sensitive data and wreak havoc on your organization.

To prevent this from ever happening to you, we're going to explore ten essential practices for securing your API in this article.

Many best practices only become sustainable when supported by DevSecOps, making it easier to continuously apply and monitor how to secure api endpoints.​

What Is API Security?

API security is a subset of cyber security that identifies and addresses API cyber threats and vulnerabilities. It uses various techniques and best practices to protect sensitive information from being exploited by users, including those inside and outside your organization.

Since APIs operate with sensitive data, they are often the subject of many types of cyberattacks.

Failing to secure or maintain your API correctly could lead to many serious repercussions, including but not limited to:

• Loss of customer data
• Unauthorized access to sensitive information
• Fraudulent transactions

There has been a dramatic shift in the API landscape of how organizations view APIs.

As Shawn Smiley, CTO at Achieve Internet, pointed out, initially, APIs were only used by development teams to facilitate their internal processes, so there wasn’t much consideration as to the ramifications of those APIs getting exposed.

As of 2021, billions of API records have been stolen as a result of API vulnerabilities and logic flaws, including major corporations such as Venmo, Facebook, and the USPS.

As the internet has grown and organizations have found new ways to leverage their APIs, things have become siloed, providing more opportunities for hackers to exploit vulnerabilities.

Now, organizations are becoming more proactive, trying to find ways to thwart attacks before they happen.

For that reason, following API security best practices is vital for protecting your company, clients, and bottom line.

10 API Security Guidelines and Best Practices

On average, API data breaches cost companies $3.81 million, excluding what IBM considers "mega breaches," which cost corporations north of $50 million on average.

Combined with the fact that almost 25 percent of Americans won't do any business with a data-breached organization, you need to understand basic API security measures to avoid becoming a statistic.

Below are ten essential API security best practices that every modern developer should know to keep their data safe.

1. Authentication & Authorization Protocols

API security begins with authentication and authorization protocols.

They help prevent API users from gaining access to data that doesn't belong to them or information they aren't allowed to see - the groups of vulnerabilities that belong to the top of the OWASP API Security Top 10 list.

Recommended: What is the OWASP API Security Top 10 List?

This is especially important when dealing with sensitive financial, healthcare, and government records since without proper API authentication and authorization protocols in place, hackers can exploit that data for personal gain.

Some of the examples of authentication and authorization protocols include:

• Basic Auth
• OAuth2
• OpenID
• SAML
• TLS
• JWT

2. Encryption for Data in Transit, at Rest, and During Storage

Although authentication and authorization are arguably the most crucial elements of API security, data encryption is just as important.

Once data enters the API, using encryption prevents other users from accessing it without authorization.

This means creating data encryption regardless of its state - whether it's stored, being transferred across a network or the internet, or sitting at rest.

Data at rest is any API data saved on a computer. You can protect it with AES 256-bit encryption using the industry-standard Advanced Encryption Standard (AES) algorithm, called Rijndael cipher.

You can similarly secure stored data while encrypting transfer data with SSL/TLS using 2048-bit encryption.

Properly encrypted data will protect against security breaches related to sensitive data, among other things.

3. Data Integrity Checks

Regular data integrity checks ensure that sensitive data has not changed before, after, or during transit.

Hashing is one of the most common methods of performing such checks. Once you hash the data, you can compare the hashed value with that of the original.

Properly executed data integrity checks will ensure that the information received matches the information sent by a server or stored on a hard drive.

Integrity checks help developers protect their resources by ensuring API requests are processed securely and validated against a set of standardized policies.

4. Logging Of API Activity For Analysis

One of the best API security practices includes logging auditable events like failed logins or large transactions for analysis purposes.

Insufficient logging ranks 10th in the OWASP list, meaning it's a significant security risk that can result in your systems failing to trigger any alarms whenever an active attack happens.

Additionally, it would be challenging to prove that a hacker committed a crime or troubleshoot any bugs or vulnerabilities post-launch without any logs.

Adequately implemented security logs allow you to keep a close watch over users and any suspicious activity.

Once you have narrowed down a suspicious source, you can construct some thresholds, rules, or parameters to protect data further.

5. Regular Code Reviews

Code reviews are a tried-and-tested way to increase software quality. That's why regular code reviews will help you identify any API vulnerabilities before attackers can exploit them.

You can host regular code reviews in several ways. For instance, you may want to schedule team meetings at least once per month to go over any changes and ensure your API team reviews any relevant code changes, especially when it comes to open-source tools.

A combination of manual and automated code reviews will give you an edge over cybercriminals.

To have all of the bases covered, either security professionals or penetration testing tools should regularly analyze public APIs to identify vulnerabilities before hackers can take advantage of them.

6. Two-Factor Authentications

Websites, API services, and cloud apps often become targets of successful cyberattacks because of poorly implemented basic authentication.

Two-factor authentication, sometimes called multi-factor authentication, takes the weakness out of single-source sign-on by requiring two steps to access user data.

Entering the correct username and password combination will require the user to submit a second authentication factor (be it a code sent to their email address or phone), providing a secondary layer of protection.

Three basic auth types you can use for your API are as follows:

• unique knowledge (a PIN)
• unique items (a mobile phone)
• unique biometrics (a fingerprint)

Implementing two-factor authentications stops hackers dead in their tracks. So it's no surprise that 2FA is considered a must for essential API security.

7. Using API Gateways

Gateways help API providers protect their resources by ensuring all requests are processed securely and validated against a set of standardized policies.

With API gateway security in place, you won't have to worry about securing your API endpoint directly. Instead, they provide the same layer of protection as firewalls do for servers and networks: they sit between the client and your protected backend services.

Your API gateway will vet any incoming requests from authorized users and direct them through a management system for further review.

The gateway's primary functions depend on the goals of implementation. Most gateways focus on the following security mechanisms:

• Implementing safety policies
• Suspicious activity alerts
• Additional security protocols

8. Implementing Proper API Testing Procedures

Testing software checks all the boxes in terms of API quality and security issues: it identifies bugs or malfunctions before they reach your user base while also strengthening the source code.

A variety of methods exists to comprehensively test your API, including (but not limited to):

• Load testing
• Websocket testing
• Penetration testing
• Fuzz testing
• Validation testing
• UI testing
• Runtime and error detection

Recommended: A Complete List of API Terms You Should Know

Each of these manual or automated tests can uncover new security issues and vulnerabilities that expose your API to hackers.

When developers have access to well-polished API documentation, they can run their own tests to ensure their API works as expected.

Manual testing is a good option if you build an API with public access or achieve widespread adoption among developers.

However, if only internal business units have access to your API, automated testing is the best way to keep costs within budgetary constraints.

To combat the rise of API breaches, APIsec offers a free penetration test that entails a complete assessment of your API. Sign up today to uncover the hidden vulnerabilities hackers can use to steal your data.

9. Throttling Requests With API Quotas

If you want to prevent your API infrastructure from being overloaded by too many requests at once - including DDoS and brute force attacks, it's best to cap API requests with some type of rate limits.

Rate limits are an essential part of API security, protecting vital software resources.

They work by restricting the number of API requests or the amount of traffic an API can process over a given period of time.

If an application exceeds the rate limit, the system will block incoming traffic from a given user or IP address and generate an error code.

Throttling API limits is one of the best ways to prevent API abuse. This way, you won't have external users overwhelming your API with too many requests per second (RPS), putting a strain on backend resources and potentially slowing system performance while pushing out legitimate traffic.

10. Addressing Excessive Data Exposure

The final API security practice to keep in mind is limiting unnecessary information spread. Regardless of the purpose of your API, it's essential to limit the amount of data revealed to the end-user whenever an API request is executed.

When it comes to API data management, the golden rule goes as follows: Don't let users send more information than they need - because that creates a security vulnerability, putting your API at risk.

If an API client sends too much unnecessary information in their request, set up an API endpoint that returns what's necessary and leaves out the rest.

11. Single Source of Truth

Organizations need to incorporate ways of publishing API documentation into a central portal as part of their CI/CD processes. This way, there is a single source of truth of what APIs are available, where they’re located, and who is responsible for them.

Commonly, this includes setting up a governance layer at an API layer and abstracting your API infrastructure from your back-end and front-end systems so that it acts as a glue between your clients and your target back-end systems.

That way, you can do centralized governance at an API infrastructure or API platform layer.

This enables you to onboard your developers as well as internal and external partners and provides them with a standardized approach for onboarding and API documentation - all while version management and revision control empower you to handle things as APIs change regularly.

12. Prioritize API Governance & Risk Assessment

For many organizations, governance only becomes a concern after APIs are published. This approach doesn’t work because potential customers will go elsewhere to if there's inadequate documentation.

Governance needs to be built in from the beginning and enforced into the development pipeline. Taking a bottom-up approach to governance can create subjectivity and avoid limitations due to a sub-committee of only a few people who don’t understand every aspect of the APIs.

Many organizations without this governance have published and unpublished APIs, creating vulnerabilities. These APIs need to be audited to document each API’s type of risks and how to mitigate these risks.

13. IP Whitelisting

The use of IP whitelisting as a security measure provides a good base for API security but should be complemented with additional security measures.

Smaller organizations with minimal APIs may consider this an option, but it should still include a zero-trust model.

They should be combining IP whitelisting with other things such as layered security and geofencing to avoid over-relying on one form of protection.

14. Leverage DevOps

APIs have fundamentally changed how often code is pushed to production. Classic security testing doesn’t necessarily operate at the speed of DevOps.

Therefore, tools and technologies that automate the process and are baked into the development cycle help organizations stop relying on reactive methods to circumvent attacks.

Software configuration analysis tests need to be included in the process to avoid security misconfigurations. With the help of API management solutions, organizations can achieve granular control to monitor and mitigate risks continuously.

Before implementing best practices, it helps to clarify common api terms so your team speaks the same security language. ​

Protect What Matters Most With Better API Security

As more and more applications enter the marketplace, API security matters more than ever before.

No matter how impervious you feel, the fact is that millions of cyberattacks have been obtaining sensitive data throughout 2021 - with no signs of the alarming trend slowing down anytime soon.

API consumers depend on providers to keep their personal data secure. When a data breach happens, the risks could be high:

• lost revenue
• public embarrassment
• fines from regulatory agencies like FERC or PCI DSS (in the case of financial institutions)
• a permanently damaged reputation from users who will likely take their business elsewhere.

But it doesn't have to be this way.

Since its inception in 2018, APIsec has been offering automated, continuous, and comprehensive API management solutions that constantly test your APIs for any vulnerabilities while costing a fraction of what you'd need to pay for manual penetration testing.

As a fully automated program, APIsec can be configured within your continuous integration pipeline to stop malicious users before they can exploit any vulnerabilities.

Are you interested to see our API security programs in action? Get in touch with our team today to schedule a free consultation.

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FAQs

1. How often should I audit my APIs for security?‍

Security reviews work best as an ongoing process: automated checks on every release and major change, with deeper manual or red-team style audits at regular intervals (for example, quarterly or semi-annually for high-risk APIs). Continuous testing plus scheduled audits keep drift under control.

2. What role does regular code review play in identifying API vulnerabilities?‍

Regular code review catches insecure patterns early, such as missing authorization checks, unsafe input handling, or hard-coded secrets. Peer review also helps ensure security requirements are actually implemented, not just documented.

3. Are public APIs more vulnerable than private APIs?‍

Public APIs face more probing because any attacker can reach them, so mistakes surface faster. Private APIs feel safer but become just as dangerous when internal trust is assumed, and controls, monitoring, and testing are weaker.

4. Is it safe to use third-party API security tools?‍

Safety depends on the vendor’s own security posture, data-handling practices, and compliance, outlined in the best API security testing tools guide. Due diligence around encryption, access controls, logging, and certifications makes third-party tools a strong extension of in-house defenses.

5. How does rate limiting prevent API abuse like DDoS and brute force attacks?‍

Rate limiting caps how many requests a client, IP, token, or user can send in a given window. Limiting speed and volume slows credential stuffing, brute force, and volumetric floods so other controls and humans have time to respond.

6. How do I know if my API has been breached?‍

Warning signs include unusual spikes or patterns in traffic, access from unexpected locations, large or atypical data transfers, and log entries showing repeated errors or unauthorized object access. Strong observability and alerting make those signals visible in time to investigate. 

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