HTTP Headers Analysis for https://calibreapp.com

Detected Technologies from Headers

See all in URL Inspect 3

AWS CloudFront

Cloudflare CDN

Render

HTTP Security Headers

Status

Strict-Transport-Security

Missing

Not configured

Content-Security-Policy

Missing

Not configured Analyze

Content-Security-Policy-Report-Only

Missing

Not configured Analyze

X-Frame-Options

Missing

Not configured

X-Content-Type-Options

Missing

Not configured

Referrer-Policy

Missing

Not configured

Permissions-Policy

Missing

Not configured

Recommendations

• Add Strict-Transport-Security header with max-age of at least 1 year
• Add Content-Security-Policy header to prevent XSS attacks
• Add X-Frame-Options: DENY or SAMEORIGIN to prevent clickjacking
• Add X-Content-Type-Options: nosniff
• Add Referrer-Policy header (recommended: strict-origin-when-cross-origin)
• Consider adding Permissions-Policy to control browser features

Performance Headers

Connection

Performance

close

Transfer-Encoding

Performance

chunked

Vary

Performance

Accept-Encoding

connection: close
transfer-encoding: chunked
vary: Accept-Encoding

Caching Headers

Cache-Control

Caching

public, max-age=0, s-maxage=3600, stale-while-revalidate=60

Etag

Caching

W/"22764-1778137445000"

Last-Modified

Caching

Thu, 07 May 2026 07:04:05 GMT

cache-control: public, max-age=0, s-maxage=3600, stale-while-revalidate=60
etag: W/"22764-1778137445000"
last-modified: Thu, 07 May 2026 07:04:05 GMT

Content Headers

Content-Type

Content

text/html;charset=utf-8

content-type: text/html;charset=utf-8

Server Headers

Server

cloudflare

server: cloudflare

CORS Headers

No CORS headers found

Cookies Headers

No cookies headers found

Other Headers

Alt-Svc

Other

h3=":443"; ma=86400

Cf-Cache-Status

Other

DYNAMIC

Cf-Ray

Other

9f83fae4cc2dd643-IAD

Date

Other

Sat, 09 May 2026 08:55:11 GMT

Rndr-Id

Other

ac66f629-92c7-400f

Via

Other

1.1 397dd692cad53f0026fab5b236c0a518.cloudfront.net (CloudFront)

X-Amz-Cf-Id

Other

gq5zPVX59VV7OMu87L8RUR_K7kRWtRi2I2Z3aJIHJ6QRRGhGF4-0FQ==

X-Amz-Cf-Pop

Other

IAD55-P3

X-Cache

Other

RefreshHit from cloudfront

X-Render-Origin-Server

Other

Render

alt-svc: h3=":443"; ma=86400
cf-cache-status: DYNAMIC
cf-ray: 9f83fae4cc2dd643-IAD
date: Sat, 09 May 2026 08:55:11 GMT
rndr-id: ac66f629-92c7-400f
via: 1.1 397dd692cad53f0026fab5b236c0a518.cloudfront.net (CloudFront)
x-amz-cf-id: gq5zPVX59VV7OMu87L8RUR_K7kRWtRi2I2Z3aJIHJ6QRRGhGF4-0FQ==
x-amz-cf-pop: IAD55-P3
x-cache: RefreshHit from cloudfront
x-render-origin-server: Render

Recommendations

Enable compression (gzip/brotli) to improve performance