What is IndexNow and how do you verify it is working?

IndexNow is a protocol introduced by Microsoft and Yandex in 2021. A site sends a short request naming URLs that changed, and participating engines fetch them promptly instead of waiting for the next scheduled crawl. Submitting to any participating engine shares the notification with all of them. Participants include Bing, Yandex, Naver, Seznam.cz, and Yep; Bing's index also feeds Microsoft Copilot. Google has tested it but does not participate, so Google discovery still relies on sitemaps, links, and Search Console.

You generate a key, a string of 8 to 128 hexadecimal characters, and host a file named after the key at your site root, for example /d13974ad42904661432758ffee342f26.txt, containing the key itself. This proves you control the host. Then you submit URLs either with a GET request naming one URL and the key, or a POST to the API with a JSON body listing up to 10,000 URLs, the host, and the key. The engine verifies the key file and queues the URLs.

First, request the key file directly and confirm it returns 200 with the key as its only content and no redirects. Second, submit one recently changed URL and confirm a 200 or 202. Third, open Bing Webmaster Tools, go to the IndexNow section, and confirm the submission appears with a timestamp. SerionFlow's free IndexNow checker runs the key-file and reachability tests on any domain so you can see whether a setup is valid before debugging submissions.

Note that an accepted submission means the engine has been told about the URL, not that it has been indexed. Indexing remains the engine's decision based on the page's quality and the site's standing.

The key file redirects, for example from http to https or from non-www to www, so the engine cannot verify it. The key file is served with an HTML wrapper by a CMS route. Submitted URLs use a different host from the declared one. The site submits every URL on every deploy, hits rate limits, and the important changes are lost in noise. And a CDN or firewall blocks the engine's verification fetch.

Sites that add and update pages every week benefit most, because the alternative is waiting days for a Bing recrawl. The right pattern is to submit changed URLs as part of the publish step. SerionFlow does this on Pro and Agency plans: when Bing Webmaster Tools is connected it submits eligible changed URLs to Bing directly and sends IndexNow notifications that reach the other participating engines, without any per-deploy scripting on your side.

It does not affect Google. It does not promise indexing or ranking on any engine. It does not replace sitemaps, which engines still use for discovery and freshness. And it does not validate page quality; a thin page submitted promptly is a thin page indexed promptly, or not at all. Treat it as a delivery mechanism for pages that already deserve indexing.