index.md

---

title: 428 Precondition Required
slug: Web/HTTP/Status/428
spec-urls: https://www.rfc-editor.org/rfc/rfc6585#section-3

---

{{HTTPSidebar}}

The HTTP 428 Precondition Required response status code indicates that the server requires the request to be conditional.

Typically, this means that a required precondition header, such as {{HTTPHeader("If-Match")}}, is missing.

When a precondition header is not matching the server side state, the response should be {{HTTPStatus(412)}} Precondition Failed.

Status

428 Precondition Required

Specifications

{{Specifications}}

See also

• HTTP conditional requests

• {{HTTPHeader("If-Match")}}

• {{HTTPStatus(412)}}