Free SEO and GEO Tools

These tools cover common checks in technical SEO and GEO. They are free and need no sign-up. Anything you paste is processed only in your browser and never uploaded.

Structured data

Schema Visualizer

Draws JSON-LD as an entity graph, auto-fixes common price, date and availability errors, and explains in plain words what machines read.

On-page SEO

SERP Snippet Preview

Measures titles and descriptions in pixels to show whether they get truncated, on desktop and mobile.

GEO

AI Crawler robots.txt Checker

Shows whether GPTBot, ClaudeBot, PerplexityBot and 20+ other crawlers can fetch a path, and which rule decides it.

When to use each tool

Schema Visualizer

Use it after shipping structured data or when you take over a new site. Google’s Rich Results Test tells you which fields are missing, but not how many entities a page declares or how they connect. This tool draws the JSON-LD as a graph, so you can see whether the same brand is defined several times, whether an article’s author points to the right Person, and whether @id values are written consistently. Format errors in prices, dates and availability are fixed in one click, and the “What machines read” view turns the markup into plain words for people who do not read code.

Open the Schema Visualizer

SERP Snippet Preview

Use it while writing titles and meta descriptions. Google truncates titles by pixel width, so character counts are only a rough guide, especially when a title mixes Latin and CJK text. The tool measures text in the font Google uses, shows desktop and mobile results side by side, and checks whether your target keyword sits in the first half of the title.

Open the SERP Snippet Preview

AI Crawler robots.txt Checker

Use it before and after changing robots.txt, especially when you want AI search engines to cite you while opting out of AI training. The tool follows RFC 9309 to decide whether 20+ AI and search crawlers may fetch a path, and shows which line decided it. A common mistake it exposes: once a crawler has its own group, it no longer reads the User-agent: * rules.

Open the AI Crawler robots.txt Checker

Notes

• The schema visualizer and the AI crawler checker can fetch a URL for you through our server, with rate limits and a 10-minute cache. You can also copy and paste; each tool page explains how.
• Checks follow schema.org, Google Search Central documentation and RFC 9309. When Google’s requirements change the tools are updated, and each page shows its update date.
• The tools report what the markup and rules say; they do not replace real data in Google Search Console.
• Found a bug or want a new tool? Reach me on GitHub.

For articles on structured data, robots.txt and AI search, see articles I wrote at Jindouyun SEO.