BAD SKY.NET

Crawler Access Checker

Check which bots and crawlers can access your website via robots.txt analysis.

What is a crawler access checker?

A crawler access checker fetches the robots.txt file of any website and simulates how each known bot interprets it. Instead of manually reading the file and reasoning about which directives apply, the tool does the matching for you — exact user-agent rules first, wildcard fallback second, longest-path-wins resolution, and Allow-wins-on-tie tie-breaking, exactly as specified in RFC 9309.

This is useful for site owners who want to audit their crawl policies, SEO professionals checking that search engines are not accidentally blocked, and developers validating a new robots.txt before deploying it.

robots.txt directives explained

A robots.txt file consists of one or more rule blocks, each targeting a specific user-agent. Each block can contain the following directives:

User-agent

Identifies which bot the following rules apply to. Use * as a wildcard to match all bots not covered by a specific rule block. Multiple User-agent lines can share the same block.

Disallow

Tells the bot not to crawl URLs that start with the given path. Disallow: / blocks the entire site. Disallow: /admin/ blocks only pages under /admin/.

Allow

Explicitly permits crawling of a path that a broader Disallow would otherwise block. When a path matches both Allow and Disallow with equal specificity, Allow wins.

Crawl-delay

Requests that the bot wait the given number of seconds between consecutive requests. Not supported by Googlebot, but respected by Bingbot, Yandex, and many others. Values above 10s may slow down indexing.

Sitemap

Points crawlers to the location of your XML sitemap. This directive sits outside of user-agent blocks and applies globally. You can include multiple Sitemap lines for multiple sitemap files.

Longest-match rule

When multiple Allow and Disallow patterns match a path, the longest (most specific) pattern wins. This means a narrow Allow can always carve out an exception inside a broad Disallow block.

How to control which bots can crawl your site

Controlling crawler access starts with understanding which bots are visiting your site and what you actually want them to do. Here is a practical step-by-step approach:

1.
Check what you currently have
Paste your domain into this tool to see how each known bot is treated right now. If the tool reports "No robots.txt", all bots are allowed everywhere by default.
2.
Decide which bots you want to allow
Search engine bots (Googlebot, Bingbot) help with organic traffic. AI training bots consume bandwidth without direct benefit unless you want your content in training data. Scrapers rarely add value.
3.
Use the Generator below
Use a template or write rules manually in the Generator section. Add explicit rules for any important bot, and use a wildcard rule as the default for all others.
4.
Use the path tester to verify rules
After writing your rules, paste them into the Path Tester and check specific URLs against the bots you care about. Confirm Googlebot can access your homepage before deploying.
5.
Deploy and re-check
Place the file at the root of your domain (https://yourdomain.com/robots.txt), then run this tool again with the Refresh option to confirm the live file matches your intent.

Search engines vs AI bots — what should you block?

Not all crawlers serve the same purpose. Understanding the difference helps you make an informed policy decision.

Search engine bots
  • • Index your content for organic search results
  • • Blocking them removes you from search rankings
  • • Googlebot, Bingbot, DuckDuckBot
  • • Generally well-behaved and respect crawl-delay
  • Recommendation: Allow
AI training bots
  • • Collect content to train large language models
  • • No direct SEO benefit to site owners
  • • GPTBot, ClaudeBot, Google-Extended, PerplexityBot
  • • Blocking has no impact on search rankings
  • Recommendation: Your choice
Scrapers
  • • Extract content for competitive intelligence or resale
  • • Can generate significant server load
  • • CCBot, Bytespider, Scrapy, Diffbot
  • • Disrespect rules more often than legitimate bots
  • Recommendation: Block

Note: robots.txt is a voluntary standard — malicious scrapers will ignore it. It is most effective against well-behaved bots. For full protection against abusive traffic, combine robots.txt with rate limiting and a WAF.