DevUtilsNow
Browse tools
// http header · response header

Last-Modified

When the resource last changed

What the Last-Modified header does

Last-Modified is the date a resource last changed. Clients use it with If-Modified-Since for conditional requests — a coarser alternative to ETag when a precise version identifier isn't available.

Example

Last-Modified: Tue, 18 Aug 2026 07:28:00 GMT

Where it's used

Last-Modified is a response header. Response headers are sent by the server to describe the response and tell the client how to handle it.

Other response headers

Content-Encoding Content-Disposition ETag Last-Modified Location Set-Cookie Server Retry-After WWW-Authenticate
TOOL

HTTP Headers Parser

Turn a block of raw headers into readable JSON.

REFERENCE

All HTTP Headers

Common request, response, caching, CORS, and security headers.

GUIDE

How to Read and Parse HTTP Headers

The anatomy of headers and how to work with them.