In app development, especially when building modern APIs and web apps, security is non-negotiable. While tools like HTTPS are standard, developers often overlook security headers, which are one of the simplest, most effective ways to harden your application.
As an experienced app development agency, we recommend security headers for every modern API and web application. They’re lightweight, easy to implement, and offer tremendous protection against common web attacks without impacting performance.
These headers are often disabled by default in modern platforms for backward compatibility, allowing older systems to function as expected. But for newer apps and APIs, enabling them requires little to no change and significantly increases your app’s security posture. Let’s dive into security headers below.
Why Use Security Headers?
Security headers act as a first line of defense, complementing HTTPS and guarding your application against threats like:
They are particularly valuable for APIs and single-page apps, where client-side execution and data transfer are frequent.
Security Headers That You Must Use for APIs and Web Apps
Here’s a breakdown of the must-use security headers, their sample values, and what each does:
| Header Item | Sample Value | Purpose |
| Strict-Transport-Security | max-age=31536000 | Instructs browsers to only connect via HTTPS for one year. Prevents downgrade attacks and HTTP hijacking. |
| X-Frame-Options | DENY | Blocks your site from being embedded via iframes, mitigating clickjacking attacks. Use SAMEORIGIN or allow-list domains if needed. |
| X-Content-Type-Options | nosniff | Prevents MIME-type sniffing, reducing the risk of script injection and cross-site attacks. |
| Referrer-Policy | no-referrer | Enhances privacy and prevents sensitive URL data from being leaked to other domains. Can be skipped if system defaults are secure. |
| Content-Security-Policy | default-src https: ‘unsafe-eval’ ‘unsafe-inline’; img-src https: data:; object-src ‘none’; font-src https: data: | Protects against XSS attacks by controlling sources of executable code and resources. |
| object-src | none | Blocks legacy plugins (like Flash or Java), which can be exploited to run malicious code. |
| base-uri | none | Prevents injection of <base> tags, which attackers can abuse to rewrite script or link paths. |
| Access-Control-Allow-Origin Access-Control-Allow-Credentials Access-Control-Allow-Methods Access-Control-Allow-Headers |
No value set by default | By default, cross-origin requests are blocked. If you enable them (* or specific domains), ensure it’s intentional. Broad access reduces security. |
Bonus Tip: Caching Securely with Cache-Control Headers
While configuring your app, don’t forget to optimize caching. If you have static assets (images, fonts, stylesheets) that rarely change, especially those with content-based hashes in their URLs, apply the following:
Cache-Control: public, max-age=31536000, immutable
This lets the browser store these files indefinitely, improving speed and reducing load without the risk of serving stale content. Be careful to use this only on assets with hashed filenames to avoid cache mismatch.
Final Thoughts
Security headers are a low-cost, high-reward addition to any app’s security stack. Whether you’re building an app in-house or partnering with an app development agency to do so, implementing these headers early in the app development lifecycle ensures your APIs and web apps are secure, fast, and future-proof.
Want help implementing modern best practices in your apps? Contact Uplancer, your trusted partner for building secure and scalable digital products.
