Web Application Security Checklist: 10 Improvements For the API-Driven Era

The importance of security in web applications can’t be understated. Web applications and APIs play a central role in our personal and professional lives, and are an integral part of our day-to-day interactions with the world, for better or for worse. 

As AI accelerates development to unprecedented speeds and APIs become the foundation of modern applications, the security landscape has fundamentally changed. Traditional security practices struggle to keep pace with AI-driven code generation and the exponential growth of API endpoints.

In this article, we’ll discuss the key considerations for securing modern web applications and APIs. To make it as targeted as possible, we’ve built a checklist of ten improvements that can help improve the security of your applications in an AI-accelerated development world. 

By following these best practices and taking a proactive approach to application security, you can protect your users’ data and ensure the integrity of your web applications and API ecosystem.

Web Application Security Checklist

Securing a web app requires the regular review and improvement of existing security measures. Although web security and vulnerabilities are constantly changing, the practices below represent the most critical security priorities for 2025. With AI tools exponentially accelerating code production, these foundational practices become even more critical as the volume and velocity of development increases. 

Here is a prioritized list of the most important things to check when building and securing your web apps and APIs, ordered by their importance in today’s threat landscape. In each point, we also are sure to mention how to implement each suggestion and which vulnerabilities are addressed by implementing it. With that, let’s get started.

1. Discover and Secure Your Complete API Ecosystem

APIs form the foundation of digital experiences and represent the most rapidly expanding attack surface. The first and most critical security measure is to discover and secure your complete API ecosystem. Unlike traditional web applications with visible interfaces, APIs often proliferate without proper governance and create “shadow APIs” that security teams don’t know exist.

API discovery should start from your source code repositories to understand your complete API attack surface. This approach reveals not just public endpoints, but also internal APIs, microservices communications, and APIs created during rapid development cycles. By analyzing where your code lives, you can instantly identify which applications handle sensitive data, how frequently they change, and what technologies they use.

Key elements of comprehensive API security include:

• Complete API discovery. Use source code analysis to identify all APIs, including shadow APIs that emerge outside traditional governance. This ensures no API goes unprotected as development accelerates.
• API-specific vulnerability testing. Test for authorization flaws, business logic issues, excessive data exposure, and broken object level authorization—vulnerabilities that are unique to API implementations.
• API authentication and authorization. Implement proper API authentication mechanisms like OAuth 2.0, JWT tokens, or API keys with appropriate scope management. Ensure that APIs enforce proper authorization at the object and function level.
• API documentation and governance. Maintain up-to-date API documentation and implement governance policies for API creation, modification, and retirement.
• Rate limiting and abuse prevention. Implement rate limiting, request size limits, and monitor for unusual API usage patterns to prevent abuse and denial of service attacks.

Modern API security tools can integrate directly into your CI/CD pipeline, automatically discover new APIs as they’re created, and ensure continuous protection as your API landscape evolves.

2. Implement Robust Authentication and Access Control

The second improvement on our list is to make sure that your application can only be accessed by authorized users to cut down the number of exploits available to potential hackers. To go further, you should also implement access control so that users only have access to the data and services that they require, nothing more. This is especially important as APIs often expose more granular access to data and functionality than traditional web interfaces.

As part of the authentication implementation, secure password storage is crucial. If passwords are easily attained by attackers, entry into the application is no longer a barrier. To further protect users and your application, multi-factor authentication should also be included in your authentication measure. Multi-factor authentication, or MFA, helps prevent unauthorized access to your web application by enforcing another step in the authentication process.

The best ways to achieve great authentication and access control standards are:

• Using secure hashing algorithms for storing passwords
• Requiring regular password updates
• Implementing authentication methods, like MFA and biometric authentication
• Implementing proper API authentication (OAuth 2.0, JWT tokens, API keys)
• Establishing role-based access control (RBAC) for API endpoints

API-Specific Considerations: Modern APIs require robust authentication mechanisms like OAuth 2.0 or JWT tokens, with proper scope management to ensure API consumers only access authorized resources. Consider implementing rate limiting and API key management for additional protection.

3. Adopt a DevSecOps Approach

A DevSecOps approach involves bringing security experts into the development process and integrating security testing into every stage of the software development lifecycle. In an era of AI-accelerated development, this approach becomes even more critical as the traditional boundaries between development and security blur.

DevSecOps aims to build security into web applications and APIs from the start, rather than adding it as an afterthought. Much of these efforts include automating security controls, especially within the CI/CD pipeline used to build the application. As AI tools generate more code than ever, automated security validation ensures that human security teams aren’t overwhelmed by the sheer volume of changes.

DevSecOps uses preventive measures against injection attacks, cross-site scripting, and sensitive data exposure to avoid introducing vulnerabilities. Many different tools can be used within DevSecOps workflows. Examples of DevSecOps tools include:

• SAST (Static Application Security Testing) tools – Analyze source code for vulnerabilities
• DAST (Dynamic Application Security Testing) tools – Test running applications and APIs
• Container security tools – Secure containerized applications and their dependencies
• Infrastructure as Code (IaC) security tools – Ensure secure infrastructure deployment
• Vulnerability management tools – Track and prioritize security issues across the development lifecycle
• Secret management tools – Protect API keys, passwords, and other sensitive configuration data

By using the tools above, a high degree of automation and security can be added when building and maintaining web apps and APIs. These tools cover everything from scanning code and applications for vulnerabilities to ensuring that the infrastructure where the code is deployed is secure.

AI-Era Considerations: As AI tools accelerate code generation, DevSecOps practices must scale to match development velocity. Focus on automated testing that provides immediate feedback to developers without slowing down innovation.

4. Validate and Sanitize All User Input

The next security measure to implement is input validation. By sanitizing and validating user input, you can prevent injection attacks (e.g. command injection or SQL injection) and cross-site scripting. These types of vulnerabilities allow attackers to execute arbitrary code and potentially access sensitive data. In an era where AI tools generate more code than ever, ensuring consistent input validation across all endpoints is non-negotiable, and yes that includes APIs that may not have user-facing interfaces

The best way to ensure input validation is cohesive is by implementing measures on the front end and the back end (server) of the application. If you are only able to implement it in a single place, always make sure that the backend input is validated and sanitized. Sanitizing user input involves removing potentially harmful characters or data from user input. Validating user input involves ensuring that the input meets certain criteria, such as being in the correct format or within a certain range.

Many frameworks and languages have tools in place that allow users to easily implement this in their code. For instance, if you are building query strings in your code by simply taking user input and pushing it into a query, this is extremely unsafe and could easily leave you vulnerable to a SQL injection attack. A better way may be to use a parameterized query, call a stored procedure, or by using an ORM solution to access and manipulate data.

API-Specific Considerations: With APIs handling diverse data formats (JSON, XML, form data), ensure validation covers all input types and considers business logic constraints specific to each endpoint.

5. Leverage Dynamic Application Security Testing (DAST)

Our fifth suggestion is to implement dynamic application security testing as part of your application security measures. Unlike traditional penetration testing, modern DAST approaches can integrate directly into your CI/CD pipeline, providing continuous security validation as code is developed and deployed. This is particularly crucial as AI-accelerated development increases the volume of code that needs security validation.

Dynamic testing evaluates applications in their running state, identifying vulnerabilities that static analysis might miss—including business logic flaws, authentication bypasses, and data exposure issues that are particularly common in API implementations. Modern DAST tools can test APIs where they actually operate, and find authorization flaws and data exposure risks that traditional security testing approaches often overlook.

There are different approaches to dynamic security testing:

• Automated pipeline testing. Integrated DAST runs automatically as part of your CI/CD pipeline, providing immediate feedback to developers with clear remediation guidance. This approach ensures that security testing keeps pace with development velocity without creating bottlenecks.
• Comprehensive security scanning. Broader security assessments that test the full range of application functionality, including complex user workflows and business logic, is particularly valuable for testing API interactions and data flows that span multiple services.
• Targeted vulnerability testing. Focused testing on specific areas of concern or newly developed features allows security teams to prioritize their efforts on the highest-risk areas of the application.

API-Specific Considerations: Modern applications require testing that understands API contracts, authentication flows, and data validation. Ensure your testing approach can handle GraphQL, REST, and other API protocols your application uses.

6. Enforce HTTPS and TLS Encryption

Our next suggestion is to ensure that your applications are secured with the use of HTTPS and TLS encryption. This approach to web application access has become a standard even for apps that are not dealing with secure data or transactions. Many customers expect that all sites will be secure, especially the ones that are handling sensitive data. This is particularly critical for API endpoints that may handle sensitive data without user awareness.

HTTPS, which stands for Hypertext Transfer Protocol Secure, is a more secure extension of the standard HTTP protocol. HTTPS establishes an encrypted connection between a web server and a client’s browser using Transport Layer Security (TLS) or its predecessor, Secure Sockets Layer (SSL).

By using the HTTPS protocol, you can ensure that your applications are being accessed securely. Part of this is done by restricting access to your application through HTTP and only allowing access through HTTPS. If there is an issue with an HTTPS connection, many browsers will let the user know that the site may not be secure, which helps to inform users to be cautious or even avoid the site until the security issue is fixed.

By implementing HTTPS and proper certificate management, you can protect data in transit from man-in-the-middle attacks and interceptions. These types of attacks are easily executed over unsecure connections and networks and can be limited by using HTTPS. Many hosting solutions make it easy to deploy and maintain your applications with secure connections using the principles mentioned above.

API-Specific Considerations: Ensure all API endpoints enforce HTTPS, including internal APIs that might be considered “safe” within a network. Certificate pinning can provide additional security for mobile applications consuming your APIs.

7. Harden Configuration and Deployment Practices

Properly configuring and deploying your web application is crucial to maintain its security. This includes:

• Following best practices when setting up your web server
• Securing your database
• Implementing secure coding practices
• Properly configuring API gateways and microservices architectures.

A big factor in this is making sure that your organization and team have the correct skillsets to handle a secure deployment of the application. This also will involve ensuring that the deployment checklist and steps that will take place are coordinated. Each step should take security best practices into account, particularly as modern applications often involve complex orchestration of multiple services and APIs.

Setting up servers and database configurations correctly is also important. Making sure that servers are hardened and not easily accessed by bad actors should not be overlooked and preferably audited as part of the deployment checklist. This is extremely important for database servers where sensitive data is stored at rest, and for API gateways that control access to your application’s functionality.

Many servers and CI/CD pipelines come built-in with the capabilities to adopt best practices. Be sure to research and follow the recommended security configuration as outlined in the docs provided by the vendors of these products.

Modern Application Considerations: With microservices and API-driven architectures, secure configuration extends to service mesh security, API gateway configuration, and proper secret management across distributed systems.

8. Secure Your Software Supply Chain

In today’s development world, applications depend heavily on third-party libraries, frameworks, and services. Supply chain security has become critical as attackers increasingly target these dependencies to gain access to applications. With AI tools accelerating development and potentially increasing dependency usage, securing your software supply chain is more important than ever.

Supply chain attacks can occur at multiple levels: compromised dependencies, malicious packages, vulnerable open-source components, or attacks on your development infrastructure itself. These attacks can be particularly devastating because they can affect every application that uses the compromised component.

Key elements of supply chain security include:

• Dependency management. Maintain an accurate inventory of all dependencies, including transitive dependencies. Use tools like Software Bill of Materials (SBOM) to track what components are in your applications.
• Vulnerability scanning. Regularly scan dependencies for the biggest web app vulnerabilities. Implement automated scanning in your CI/CD pipeline to catch vulnerable dependencies before they reach production.
• Dependency pinning. Pin dependencies to specific versions rather than using version ranges to prevent automatic updates to potentially compromised versions.
• Source verification. Verify the integrity and authenticity of dependencies through checksums, signatures, and trusted repositories. Be cautious of packages from unknown or untrusted sources.
• Regular updates. Keep dependencies updated with security patches, but balance this with testing to ensure updates don’t introduce breaking changes or new vulnerabilities.
• Build environment security. Secure your build pipelines and development environments to prevent attackers from injecting malicious code during the build process.
• Vendor risk assessment. When using third-party services or hosted dependencies, assess the security practices of your vendors and their supply chain security measures.

Many development platforms and security tools now provide supply chain security features built-in, making it easier to implement these practices as part of your standard development workflow.

9. Follow Proper Logging Practices

Monitoring and logging activity on your web application helps identify potential security threats and provides valuable information for forensic investigations in the event of a security breach. By keeping a detailed log of application events, API calls, and user interactions, it becomes easier to trace the steps of an attacker and seal vulnerabilities from being exploited in the future.

Proper logging practices also ensure that logs are not easily accessible to outside attackers. Just as internal investigators may use logs to identify how a breach occurred, attackers can also use data within the logs to plan an attack or see vulnerabilities.

When data is pushed to the logs, you should ensure that any sensitive data is masked or not included in the log statements. Data like credit card numbers, passwords, API keys, and other sensitive data should never make it into a log file without at least being masked. If an attacker gets access to a log with this type of data, it can be as detrimental as them getting access to the application itself.

Lastly, you should also ensure that debug log statements that print to a console or response are not pushed out into production code. They involve something as simple as a console.log in a JavaScript file which may expose an error occurring that the attacker could exploit.

API-Specific Considerations: API logs should include sufficient detail to track request flows across microservices while protecting sensitive data. Consider implementing correlation IDs to track requests across distributed systems and ensure API access patterns are properly monitored.

10. Establish Secure Secrets Management

Proper secrets management is crucial for modern application security, especially in cloud-native and API-driven architectures. Secrets include API keys, database passwords, encryption keys, certificates, tokens, and any other sensitive configuration data that applications need to function. Poor secrets management is one of the leading causes of data breaches and security incidents.

Sensitive information should never be hardcoded in source code, configuration files, or any other location where it might be exposed. With AI tools accelerating code generation and teams moving faster than ever, implementing proper secrets management practices is even more crucial for preventing accidental exposure.

Key elements of effective secrets management include:

• Never hardcode secrets. Avoid embedding passwords, API keys, or other sensitive data directly in source code, configuration files, or environment variables that might be logged or exposed.
• Use dedicated secret management tools. Implement solutions like HashiCorp Vault, AWS Secrets Manager, Azure Key Vault, or Google Secret Manager to securely store and manage secrets with proper access controls and audit trails.
• Implement secret rotation. Regularly rotate secrets, especially API keys and database passwords. Automated rotation reduces the window of exposure if a secret is compromised.
• Secure secret injection. Use secure methods to inject secrets into applications at runtime, such as mounting secrets as files, using init containers, or leveraging cloud-native secret injection mechanisms.
• Environment separation. Maintain different secrets for different environments (development, staging, production) and ensure that non-production secrets cannot access production resources.
• Access control and monitoring. Implement proper access controls for who can view, modify, or use secrets. Monitor secret access patterns and set up alerts for unusual activity.
• CI/CD pipeline security. Secure your build and deployment pipelines to prevent secret exposure during the development process. Use pipeline-specific secrets that are automatically injected during builds.
• Secret scanning. Implement automated scanning tools that detect accidentally committed secrets in source code repositories and alert teams immediately.

Modern development platforms and CI/CD tools provide built-in secrets management capabilities, making it easier to implement these practices without significant overhead. The key is to establish secrets management practices early in the development process and ensure all team members understand and follow them consistently.

OWASP Security Guidelines and Checklists

Beyond the core security practices outlined above, following established security frameworks provides additional depth and coverage for your application security program. The Open Web Application Security Project (OWASP) provides comprehensive resources that every security team should leverage. 

It’s good practice to make all technical participants in a project aware of these OWASP resources and use them as references during code reviews, security assessments, and deployment reviews. While the practices in this article cover the most critical areas, the following OWASP resources provide additional depth and testing methodologies that complement a robust security program.

OWASP Application Security Checklist: The OWASP Web Security Testing Checklist covers a comprehensive range of security measures including detailed testing procedures, implementation guidance, and verification steps. This checklist serves as an excellent complement to the core practices outlined in this article.

OWASP API Security Top 10: The OWASP API Security Top 10 addresses API-specific vulnerabilities like broken object level authorization, excessive data exposure, and improper assets management which are particularly relevant in modern API-driven applications.

OWASP Top 10 Web Application Security Risks: The classic OWASP Top 10 provides foundational knowledge about the most critical web application security risks and remains an important reference.

Using StackHawk for Modern Web Application Security

StackHawk takes a fundamentally different approach to application security by starting at your source code repositories to discover and protect your complete API attack surface. Unlike traditional security tools that only see public endpoints, StackHawk reveals shadow APIs, identifies sensitive data flows, and tracks development activity to ensure no API goes unprotected in an AI-accelerated development world.

StackHawk transforms security from scheduled, snapshot testing to continuous protection by integrating automated testing directly into CI/CD pipelines. By testing APIs where vulnerabilities actually exist and delivering immediate feedback to developers with clear remediation guidance, StackHawk makes security accessible to everyone involved in creating software.

The benefits of using StackHawk for modern application security include:

• Comprehensive API discovery. Starting from source code repositories, StackHawk provides complete visibility into your API landscape, including shadow APIs that traditional tools miss.
• Runtime security testing. Dynamic testing that finds authorization flaws, business logic issues, and data exposure risks that static analysis cannot detect.
• Developer-native integration. Seamless integration into development workflows, providing actionable security findings with clear fix guidance in developers’ language.
• Continuous visibility. Real-time insights into your security testing program—what’s tested, how often, and what needs attention—to enable data-driven security decisions.
• Scalable security. Automated testing that scales with AI-accelerated development, ensuring security keeps pace with innovation without creating bottlenecks.

Web Application Security FAQs

Have more questions about Web Application Security? Below we have compiled a few common questions and comprehensive answers to help you and your team keep your web applications and APIs safe.

What are the security requirements for a modern web application?

Every web application has unique security needs, but these four requirements are the most important in today’s API-driven world:

1. Strong authentication and access control. Only authorized users should access your application, APIs, and data. Use multi-factor authentication, proper API tokens, and role-based permissions.
2. Data encryption. Encrypt sensitive data everywhere—when it’s stored, when it travels between systems, and especially in API communications across networks.
3. Input validation. Never trust user input. Validate and clean all data entering your application, whether through web forms or API endpoints.
4. API security. Protect your APIs with rate limiting, proper authentication, and monitoring for attacks like unauthorized data access or excessive information exposure.

How do you maintain web application security in an AI-accelerated world?

As AI tools speed up development, security must keep pace. The key is making security automatic and developer-friendly, so protection scales with your development speed. Here’s how to maintain protection without slowing down innovation:

• Automate security testing. Build security checks directly into your development pipeline so every code change gets tested automatically.
• Track all your APIs. Use tools like StackHawk that discover APIs automatically, including “shadow APIs” that developers create outside normal processes.
• Integrate security into development. Give developers security tools they can use while coding, not after deployment when fixes are expensive.
• Stay current. Regularly update software, libraries, and dependencies. Attackers constantly target known vulnerabilities.
• Monitor everything. Log application activity and API calls to spot attacks early and investigate incidents when they happen.
• Plan for recovery. Maintain secure backups and test your restoration process regularly. Assume a breach will happen eventually.

Web Application Security Best Practices That Scale With Innovation

To ensure the security of your web application and APIs in today’s AI-accelerated development landscape, you must implement continuous security practices that scale with development velocity. This includes:

1. Comprehensive API security and discovery
2. Robust authentication and access control
3. DevSecOps integration
4. Thorough input validation
5. Continuous security testing
6. Proper encryption
7. Secure deployment practices
8. Supply chain security
9. Comprehensive logging and monitoring
10. Secure secrets management

Modern application security requires understanding your complete API attack surface and implementing security testing that integrates seamlessly into development workflows. Tools like StackHawk help bridge the gap between development speed and security rigor by discovering APIs from source code, providing continuous testing, and delivering actionable feedback to developers.

By following these best practices and implementing continuous security validation, you can ensure that your web applications and APIs remain protected against evolving threats while enabling innovation to proceed at the speed your business demands.

Looking to take the first step towards making your applications more secure in an AI-accelerated world? Sign up and try out StackHawk for free! Discover your complete API attack surface, test your applications where they actually run, and get immediate, actionable security feedback. By including StackHawk in your CI/CD pipeline, you can ensure that every commit is tested automatically and that your applications are secure before they hit production.