Robots.txt Checker Tool Development

Astro · Cloudflare Workers · Technical SEO

A focused robots.txt checker that tests whether a specific URL is allowed or blocked for Googlebot, Bingbot, image crawlers, or the wildcard user-agent, then explains the exact matching rule in plain English.

Open the robots checker

Robots.txt is one of those small files that can create very expensive confusion. A single disallow rule can block important pages, while a missing sitemap declaration can make discovery messier than it needs to be.

Most site owners do not need a full crawler just to answer one immediate question: can Googlebot crawl this URL, and if not, which line in robots.txt is responsible?

I built the robots checker as a narrow technical SEO utility. The front end collects a URL and crawler type, then the Worker fetches the site robots.txt file, parses user-agent groups, applies allow/disallow matching, and returns the deciding rule.

The result panel shows URL status, robots.txt availability, crawler tested, matched user-agent groups, sitemap declarations, and a plain-English explanation. That keeps the output actionable instead of forcing the user to read raw directives.

The tool deliberately avoids saying a page is indexed or indexable in the Google sense. Robots.txt controls crawl access, not ranking and not guaranteed indexing. That distinction is critical, so the UI says it directly.

It is designed to be used alongside the sitemap validator. Robots.txt answers whether a crawler is allowed to request a URL. A sitemap answers what the site is asking crawlers to discover. When those two disagree, the audit gets interesting.

This build turns a common technical SEO check into a fast diagnostic workflow. It is not trying to be a giant audit scanner. It answers one question clearly, shows its work, and gives the user enough context to make the next decision.

That restraint is the product strategy: useful tools beat noisy tools when the audience is trying to solve a real SEO problem.

Built as a public portfolio asset and as a practical utility: the page has to earn trust twice, once as a usable SEO tool and once as proof that the underlying engineering choices were deliberate.

Crawler selection for Googlebot, Googlebot-Image, Bingbot, and wildcard user-agent

Sitemap declaration extraction from robots.txt

Plain-English crawl-access explanation