Below is my list of top SEO tools to carry out a technical audit of a website:
Test hotlink protection
This tool is to check if Hotlink protection is being used to prevent other sites from using and linking to your images, potentially costing a large amount in bandwidth costs.
Siteliner duplicate content finder
The Siteliner tool is a free service to find duplicate content, broken links, etc.
Check grammer mistakes
Generates a list of keywords downloadable in excel csv format. Also generates a pretty cool looking word cloud based on the list keywords.
Check SEO related queries which users are searching for. It’s a really good, FREE TOOL which can help you with SEO and Content opportunities/strategies, the data is getting pulled from google suggest and related searches. You can then segment by the question prefix, e.g. how, what, why, when etc. More useful for finding content ideas and topics to write around.
Website loading speed
Test my site (thinkwithgoogle.com)
Test a site to see out it performs on a mobile and desktop device. There is a speed test score with recommendations on how to fix them.
PageSpeed Insights analyzes your web page to see how fast it loads in a Desktop PC or mobile device. It then generates suggestions to make that page faster.
Run a website speed test from multiple locations around the globe using real browsers (IE and Chrome) and at real consumer connection speeds. I recommend testing your site with the 1.5Mb 3G connection to replicate a typical mobile user. You can run simple tests or perform advanced testing including multi-step transactions, video capture, content blocking and much more.
PageSpeed Insights (with PNaCl)
Really useful plugin for the Chrome browser, for doing page speed tests on URLs that are hidden behind login screens.
Check the speed performance with data from Page speed and Yslow.
Online web check
Check your HTML, XHTML, CSS, JSON, robots.txt, and cache manifest files.
Converts your HTML code snippets into pretty-printed HTML format, which is great when you need to show HTML snippets when creating your SEO audit. Just copy the source code to the left pane, select the language and the color scheme, and click “Highlight!”.
Robots.txt Test Tool
Test if your web content can be accessed by major search engine crawlers. You can change the user-agent to: Googlebot, Googlebot (Bilder), MSNBot, Yahoo Slurp, Lycos, Seekbot, Sistrix, SearchmetricsBot, BacklinkCrawler, SEOKicks and Xovi.
Matt kersley Responsive Web Design Testing Tool
This free online tool has been built to help with testing your responsive websites to make sure the design is viewing ok in different screen sizes. You can enter your website’s URL into the address bar at the top of this page (not your browser’s address bar) to test a specific page.
Linter structured-data tool
Enter a URL in the text field to see what structured data your page contains and check the output is correct. Example structured data can be: Review ( RDFa MD ) People ( RDFa MD ) Event ( RDFa MD ) Recipe ( RDFa MD ) Product ( RDFa MD ).
Test online your Open Graph Tags for Facebook, Google+ and Linkedin. Get an overview of the valid implemented tags.
AMP Validator Web Tool
Validate your AMP pages are marked up correcty and is also a web validator, similar to the structured data testing tool.
For presenting “word clouds” in your audit, this can really improve the visual impact of reports to clients.
Jeffrey’s Image Metadata Viewer
Shows the full meta data of an image (either online or uploaded). For each image this tool shows: File Size (in kb), File Type, File Type Extension, MIME Type, Animation, Bit Depth, Color Type, Compression, Deflate/Inflate
Filter, Image Size, Interlace, Pixels Per Unit X & Y and Pixel units. Extra functionality is enabled when you use Firefox or another Gecko-based browser.
A collection of HTML head elements that are currently used by the major browsers. There is also a list of elements which are either deprecated or not supported anymore. The list includes the following elements: Meta, link elements, favicons, Social Facebook / Open Graph, Twitter cards, Google+ / Schema.org, Apple iOS, etc.
Many tools in one connected to the DNS of the domain you need to audit.
– IP History
– Reverse Whois Lookup
– DNS Propagation Checker
– Reverse NS Lookup
– Port Scanner
– Nameserver check
– IP Location Finder
– Check whether a site is accessible in Iran or China
– Get HTTP Headers
– Domain / IP Whois
– DNS & Reverse Record Lookup
– ASN Lookup
– URL / String Decode
Verify if your server or CDN supports HTTP/2.
Personal Blocklist and export sub-domains
Google plugin to block and export sub-domains. When looking for duplicate content, it’s often important to know how many sub-domains exist and are indexed by Google.
XML Sitemap validator
Check your XML sitemap(s) conform the the standard outlined in http://www.sitemaps.org/protocol.html
Hreflang tester tool
Tool from Sistrix to validate the rel=”alternate” hreflang=”x” link-attribute to make sure that Google can identify the correct geographical focus for your websites and show the correct language version or regional URL for your content. The Hreflang tester tool will check all the hreflang link-attribute markup for the multi-language content on your website.
WhatCMS.org can detect 142 different CMS applications and services that the site is using.
Detect CMS, Framework, Webserver, etc. This online free tool will analyze websites and attempt to detect the plaform, language, framework and other technologies used for your website.
Seobook robots.txt analyzer
Enter URL of your robots.txt or paste it’s contents in the box below it and the tool will test your robots.txt to see if you are blocking any content from being indexed in the search engines.
Tool to check your server headers. It gives you a vote and tells you which headers are missing.