HTTP Headers Viewer
Privacy Note: This tool displays HTTP headers sent by your browser to our server. No personal data is stored or logged.
View the complete HTTP request headers your browser sends with each web request.
Test External URL Headers
Common Header Reference
User-Agent: Identifies your browser and operating system
Accept: Lists content types your browser can handle
Accept-Language: Your preferred languages
Cookie: Contains stored cookies for the site
Referer: The previous page you came from
About HTTP Headers
HTTP headers are components of the HTTP protocol that allow clients and servers to pass additional information with requests and responses. They define the operating parameters of an HTTP transaction.
Types of HTTP Headers
- Request Headers: Sent by the client to the server (e.g., User-Agent, Accept)
- Response Headers: Sent by the server to the client (e.g., Content-Type, Set-Cookie)
- General Headers: Apply to both requests and responses (e.g., Cache-Control, Connection)
- Entity Headers: Describe the content being transferred (e.g., Content-Length, Last-Modified)
Common HTTP Headers
Request Headers
- Host: Domain name of the server
- User-Agent: Client application information
- Accept: Acceptable response media types
- Accept-Language: Preferred languages
- Cookie: Stored cookies for the domain
Response Headers
- Content-Type: Media type of the resource
- Set-Cookie: Sets cookies on the client
- Cache-Control: Caching directives
- Location: URL redirection target
- Server: Information about the server
Security-Related Headers
Modern websites use security headers to protect against common web vulnerabilities:
- Content-Security-Policy (CSP): Prevents XSS attacks by controlling resources
- X-Frame-Options: Prevents clickjacking by controlling framing
- Strict-Transport-Security (HSTS): Enforces HTTPS connections
- X-Content-Type-Options: Prevents MIME type sniffing
- Referrer-Policy: Controls referrer information sent
Example HTTP Transaction
Request:
GET /index.html HTTP/1.1 Host: www.example.com User-Agent: Mozilla/5.0 Accept: text/html,application/xhtml+xml Accept-Language: en-US,en;q=0.5 Connection: keep-alive
Response:
HTTP/1.1 200 OK Date: Mon, 23 May 2022 22:38:34 GMT Server: Apache/2.4.1 (Unix) Content-Type: text/html; charset=UTF-8 Content-Length: 138 Last-Modified: Mon, 22 May 2022 09:23:24 GMT Cache-Control: public, max-age=3600
Frequently Asked Questions
What information do HTTP headers contain?
HTTP headers contain metadata about the request or response, including content type, caching directives, authentication tokens, cookies, server information, and more. They help browsers and servers communicate effectively.
Can I see HTTPS headers?
This tool shows HTTP headers sent to our server. For HTTPS sites, the headers are encrypted during transmission but are visible to both the client and server. When testing external HTTPS URLs, we can only show response headers, not the encrypted request.
Why can't I see all headers when testing external URLs?
Some servers block header requests or restrict certain headers from being visible. Additionally, cross-origin restrictions may prevent access to certain headers. For complete header inspection, browser developer tools are more reliable.
How can I modify or remove headers my browser sends?
Browser extensions can modify headers, but most headers are set automatically by your browser. Some can be controlled through browser settings or flags, but modifying headers can break website functionality.
Note: This tool is for educational purposes. For professional header analysis, consider browser developer tools or specialized HTTP debugging proxies.