Why does it differ from the headers I see in my own browser?

This tool sends a request from our server, which means it accesses the URL under different conditions (User-Agent, cookies, etc.) than your local browser environment. Therefore, if the server varies headers based on the environment, the results may differ.

When should I use this tool?

You can use it to verify if cache settings are correctly applied for website performance optimization, or to check if necessary security headers are output during a security audit.

Is my data saved on the server?

No. Our server only acts as a proxy to query the target URL. Neither your search history nor the entered URLs are saved on our server.

What happens if security headers are not set?

While it does not mean your site will be hacked immediately, the vulnerability to attacks such as Cross-Site Scripting (XSS) and Clickjacking increases. It is highly recommended to set them, especially for sites handling personal information.

What should I be careful about when setting up HSTS (Strict-Transport-Security)?

Once HSTS is enabled, users' browsers will be forced to access via HTTPS for the specified period (max-age). If there are issues with the SSL certificate configuration, there is a risk that the site will become completely inaccessible during this period. Therefore, it is recommended to start testing with a short duration.

What is the correct way to configure cache-related headers?

A common best practice is to set a long expiration date (e.g., 1 year) using Cache-Control for static assets like images and CSS, and to set "no-cache" for frequently updated HTML files so that the server is always queried.

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http header,

HTTP Header Checker

Instantly retrieve and display HTTP response headers returned by the server.
Ideal for checking cache settings and security headers.

⚡

Instant Check

Just enter a URL

📋

Full Display

Lists all response headers

🆓

No Registration

Completely free to use

about,

About the HTTP Header Checker

HTTP headers are "behind-the-scenes configuration info" communicated between Web browsers and Web servers. This tool visualizes what response headers the server is returning for the specified URL.

It is useful for verifying cache control settings (Cache-Control), security-related headers (Strict-Transport-Security, etc.), and Web server types. It is also ideal for debugging API responses.

how to,

How to Check Response Headers

STEP 1

Enter the URL

Enter the complete URL of the page you want to check (starting with http:// or https://) into the input field.

STEP 2

Execute Check

Click the "Check Headers" button. Behind the scenes, our tool's server will initiate communication with the target URL to retrieve only the header information.

STEP 3

Analyze Results

After a short wait, a list of HTTP headers returned by the server will be displayed in a table format. Ensure that security and cache settings are as intended.

glossary,

HTTP Header Glossary

Cache-Control: A header that specifies the duration and conditions under which browsers or CDNs cache content. This is a crucial setting directly tied to site loading speed and server load.
Content-Type: Specifies the media type (MIME type) and character encoding, indicating whether the returned data is HTML, an image, etc.
Server: Contains software information (Apache, nginx, etc.) and version details of the Web server that processed the request. It is sometimes hidden for security reasons.
Strict-Transport-Security (HSTS): A security header that forces browsers to always connect to the website via HTTPS. It is recommended to prevent man-in-the-middle attacks.
X-Frame-Options: Controls whether the content of your site is allowed to be embedded within <iframe> elements on other sites. Effective for preventing clickjacking attacks.
Content-Security-Policy (CSP): A powerful security header that restricts the sources from which browsers can load resources (scripts, images, etc.). It can significantly mitigate XSS attacks.
CORS (Cross-Origin Resource Sharing): A mechanism for sharing resources across different domains (origins). Headers like Access-Control-Allow-Origin are used to specify permitted domains.
Set-Cookie: A header used by the server to instruct the browser to store cookies (data for state management). It is used for session management and user tracking.

faq,

Frequently Asked Questions (FAQ)

Q.Why does it differ from the headers I see in my own browser?: This tool sends a request from our server, which means it accesses the URL under different conditions (User-Agent, cookies, etc.) than your local browser environment. Therefore, if the server varies headers based on the environment, the results may differ.
Q.When should I use this tool?: You can use it to verify if cache settings are correctly applied for website performance optimization, or to check if necessary security headers are output during a security audit.
Q.Is my data saved on the server?: No. Our server only acts as a proxy to query the target URL. Neither your search history nor the entered URLs are saved on our server.
Q.What happens if security headers are not set?: While it does not mean your site will be hacked immediately, the vulnerability to attacks such as Cross-Site Scripting (XSS) and Clickjacking increases. It is highly recommended to set them, especially for sites handling personal information.
Q.What should I be careful about when setting up HSTS (Strict-Transport-Security)?: Once HSTS is enabled, users' browsers will be forced to access via HTTPS for the specified period (max-age). If there are issues with the SSL certificate configuration, there is a risk that the site will become completely inaccessible during this period. Therefore, it is recommended to start testing with a short duration.
Q.What is the correct way to configure cache-related headers?: A common best practice is to set a long expiration date (e.g., 1 year) using Cache-Control for static assets like images and CSS, and to set "no-cache" for frequently updated HTML files so that the server is always queried.

scenes,

Use Cases

🔍

Check SEO & Redirects

Verify if 301/302 redirects are set correctly and returning the appropriate status codes.
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Audit Security Headers

Check if HTTP headers required for security (like HSTS) are correctly output.