Home Monitors Features Pricing Free Tools Log In Sign Up

Home
Free tools
HTTP header reference
If-Unmodified-Since

← All headersRequest header

What is an If-Unmodified-Since header?

Makes the request conditional on the resource not having changed since the given date.

Other Request headers

Accept Accept-Charset Accept-Encoding Accept-Language Access-Control-Request-Method Access-Control-Request-Headers Authorization Cookie Expect Forwarded From Host If-Match If-Modified-Since If-None-Match If-Range Max-Forwards Origin Proxy-Authorization Range Referer TE User-Agent DNT X-Requested-With X-Forwarded-For X-Forwarded-Host X-Forwarded-Proto Upgrade-Insecure-Requests Save-Data Sec-GPC

Kawze

Uptime monitoring that tells you the moment something breaks.

30-day money-back guarantee on every paid plan. Details

Proudly made in Redditch, England.

ProductHome Pricing Enterprise Uptime Bot API Docs Log In Sign Up

FeaturesAll Features Website Monitoring Keyword Monitoring SSL Certificate Monitoring DNS Monitoring Response Time Monitoring Heartbeat (Cron) Monitoring

MonitorsAll Monitor Types HTTP Monitor Heartbeat Monitor Domain Health Monitor Response Time Monitor Visitor Monitor Cache Warming Monitor Cloudflare Cache Monitor Port/TCP Monitor

Free ToolsAll Free Tools Is It Down?Is It Down For Everyone?Random String Generator Base64 Encode / Decode JSON Formatter / Validator HTTP Status Code Reference HTTP Header Reference What Is My IP Address?Diff Checker Markdown to HTML Converter SSL Certificate Checker Cron Expression Explainer URL Encoder / Decoder

CompareAll Comparisons vs UptimeRobot vs Statuspage vs Better Stack vs Site24x7 vs Pingdom vs Uptime.com vs Uptime Kuma vs Oh Dear vs Cronitor vs StatusCake vs Freshping

LegalAll Legal Terms and Conditions Privacy Policy Refund Policy Data Retention Policy GDPR DPA GDPR Data Request Trademark Notice Report Abuse Contact Us

© 2026 Kawze. All rights reserved. Peterbrook Trading Ltd, trading as Kawze, registered in England and Wales under company number 15540069. Registered address: Peterbrook Close, Redditch, B98 7YF, United Kingdom.