Robots.txt Checker Tool Build
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.
The Problem
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?
The Build
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 SEO Judgment
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.
The Takeaway
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.
What I Built
- Astro tool page with focused URL-testing interface
- Cloudflare Worker endpoint for robots.txt fetching and parsing
- Crawler selection for Googlebot, Googlebot-Image, Bingbot, and wildcard user-agent
- Matched allow/disallow rule output with line number
- Sitemap declaration extraction from robots.txt
- Plain-English crawl-access explanation
- WebApplication schema, breadcrumbs, OG image, and share strip
More from the tool suite
Need a technical SEO tool or audit workflow built?
I build practical SEO systems that do one useful job clearly, then wire them into the site, schema, analytics, and conversion path around them.
Book Your SEO Health Check → ← Back to all case studiesWant work like this?
Whether you need a technical audit, a public-facing tool, or a workflow that turns messy SEO judgment into a repeatable system, I would love to hear what you are building.