Mixed content and upgrade-insecure-requests
type: TechArticle
description: An HTTPS page that loads any subresource over HTTP is mixed content. Serve every subresource over HTTPS, and send the upgrade-insecure-requests CSP directive as a safety net.
language: en
is part of: Web Specification Studio
author: Web Specification Studio
publisher: Web Specification Studio
license: https://creativecommons.org/licenses/by/4.0/
date modified: 2026-06-08T20:15:00.000Z
citation: W3C — Mixed Content
  type: CreativeWork
  publisher: W3C
citation: W3C — Upgrade Insecure Requests
  type: CreativeWork
  publisher: W3C
citation: MDN — Mixed content
  type: CreativeWork
  publisher: MDN
citation: MDN — CSP: upgrade-insecure-requests
  type: CreativeWork
  publisher: MDN

Web Specification Studio
type: WebSite

Web Specification Studio
type: Organization

breadcrumb
type: BreadcrumbList
item list element: Home
  type: ListItem
  position: 1
  item: https://webspecification.com/
item list element: Spec
  type: ListItem
  position: 2
  item: https://webspecification.com/spec/
item list element: Security
  type: ListItem
  position: 3
  item: https://webspecification.com/spec/security/
item list element: Mixed content and upgrade-insecure-requests
  type: ListItem
  position: 4
  item: https://webspecification.com/spec/security/mixed-content/