Screaming Frog is one of the oldest SEO tools on the market, but is still a go to one, for both newbies and advanced users. It is definitely among the best checkers for technical on-page SEO analysis.

Screaming Frog quickly gives you loads of important data about your site, presented in tabs by type, which you can easily filter for common technical SEO issues holding your website back from the first page. You can view, filter and sice the crawl data as you need and export in Excel.

Free desktop version works well (available for PC, Mac, Ubuntu). But to be fully equipped, you want to switch to the full paid version.

Screaming Frog free version limitations:

• Maximum 500 URI crawls (but the List mode is unlimited!)
• Not all configuration options are accessible
• You can’t save & re-upload crawls
• You can’t search for anything in the source code, collect any data from the HTML of a URL using XPath, CSS Path or regex
• You can’t connect to the Google Analytics API & pull in data directly during a crawl
• You don’t get support for any technical issues with the software

Some of the Screaming Frog’s features:

• Unlimited List mode crawler – you can upload and crawl, say, 10k URLs without buying a lisence
  Redirects autiting (saves a lot of time when you migrate)
• The Crawl Path Report to view the ‘in links’ to a particular URL (click on a URL, then ‘export’ and ‘crawl path report’)
• Ajax Crawling – crawl Ajax websites as normal
• Edit Page Title and Meta Description directly in the SEO Spider via the SERP snippet emulator! very useful
• SERP Snippets by Device – switch device type to get an idea of how your snippets display across all devices.
• SERP mode – switch to the ‘SERP mode’ to upload page titles and meta descriptions directly into the SEO Spider to calculate pixel widths and character lengths. No crawling involved in this mode, so you can test them before they are put live on a website.
• XML Sitemap Auditing – save and upload your XML sitemap in the “List” mode to get it crawled
• Canonical Errors Report – see canonicals which have no response, redirect and other errors (anything other than a 200 ‘OK’ response). Go to Reports → Canonical Errors.
• Crawling Authenticated Staging Sites – crawl sites in development, staging servers and sites which require a login to access before important site changes go live.
• Easily analyze and optimize hundreds of thousands of pages and sub-pages – this is unique
  Discover redirect chains and loops