X-Content-Type-Options: nosniff
type: TechArticle
description: The nosniff header stops browsers from guessing a response's content type. It blocks a class of attacks where a benign-looking file is interpreted as script or stylesheet.
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: 2026-05-29T09:13:20.000Z
citation: MDN — X-Content-Type-Options
  type: CreativeWork
  publisher: MDN
citation: Fetch Standard — MIME type checks
  type: CreativeWork
  publisher: WHATWG
citation: OWASP Secure Headers Project
  type: CreativeWork
  publisher: OWASP

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: X-Content-Type-Options: nosniff
  type: ListItem
  position: 4
  item: https://webspecification.com/spec/security/x-content-type-options/