The Rich Results Test is Google’s own structured data testing tool, and the fact that it comes directly from Google makes it the most authoritative reference you can use when implementing or debugging schema markup. You enter a URL or paste in code, and the tool tells you which rich result types your page is eligible for, flags any errors or warnings in your structured data, and shows you how Google renders the page’s schema.
The distinction between errors and warnings is useful. Errors mean your structured data won’t qualify for the rich result type at all. Warnings mean it qualifies but is missing recommended properties that could make the result more compelling in the SERP. Working through both categories systematically is one of the highest-leverage technical SEO tasks for pages where schema is relevant, and the Rich Results Test makes it straightforward to do so.
I use this tool constantly when implementing or reviewing structured data. For e-commerce sites with Product schema, recipe sites with Recipe schema, or local businesses with LocalBusiness schema, validating your markup with the Rich Results Test before you go live should be non-negotiable. The fact that it’s free, directly from Google, and requires no account makes it an indispensable bookmark. The only limitation is that it’s a page-level tool. For site-wide schema auditing, you’ll want to pair it with a crawler like Screaming Frog that can surface schema issues across all your pages at once.