SEO (Search Engine Optimisation) may be considered a bit of a dark art by some, but it’s an important art nonetheless. Search engines (especially Google) are often the biggest of driver of traffic to a website, drawfing social media and other channels, so it’s important to make sure that your SEO is as good as it can be from an on-site perspective. Unfortunately, SEO is sometimes considered an afterthought and considered as a reaction to a site that isn’t performing well post-launch. Avoid falling into that trap with our checklist of on-site/technical SEO considerations.

SEO checklist for developers

Please note: this list is accurate as of its publication date. SEO is constantly changing and evolving, so please understand that some of these points may change or even become obsolete as time progresses.

Technical SEO considerations – the full list

Here is the full list of technical SEO factors that will most likely affect most websites, regardless of industry/type. We’ve broken them down by sub-section:

Domain selection

If you’re at a very early stage, then even the choice in domain (heck, even the business name!) can affect SEO:

  • Keyword inclusion – If a business plans to call itself XYZ and it sells software then a domain like may be a better choice than simply, as you will increase your chances of being picked up for keywords including the word “software.”
  • TLD type – The type of TLD (top-level domain) that you choose can affect SEO from a geo-targeting perspective. For example, if you’re UK-based but plan to sell globally then a .com might be better than a as the former is considered generic (non-country-specific), however if you only sell in the UK and have no plans to sell globally then it may make more sense to use a Generic TLDs can also be designated a target country via Google Search Console, so you can use a .com but target it to the UK, for example.

Important on-page HTML elements

Some of these aren’t strictly technical considerations per se, but they’re certainly still important from an on-site SEO point of view – especially the page title, which is one of the most important on-site SEO factors.

Page titles

Page title example screenshot
Page titles are one of the most important factors in SEO. Proper keyword usage is essential, plus a well-crafted page title may improve click-through rate, further increasing your chances of being clicked on in search engines.

Make sure that page titles are roughly 55-60 characters in length and uniquely written on key landing pages, with the website/brand name at the end of it.

Learn more about page titles

Meta descriptions

Meta descriptions are the short descriptions that appear alongside your search results in search engines. They don’t influence SEO directly, however it’s still important to include keywords within them as they will be shown in bold if they match the searcher’s keyword, making them more eye-catching and therefore increasing your chances of getting clicked.

Make sure that pages have unique meta descriptions that are 155-160 characters in length (roughly one long sentence or two short sentences), which act as a brief summary of the page’s content. If it is the homepage, it can be a brief summary of the website/business as a whole.

Learn more about meta descriptions

Meta keywords

Don’t bother with the meta keywords tag… Most major search engines ignore them, and it opens up an opportunity for your competitors to see what keywords are important to you (if they check your pages’ source code). If you have already added meta keywords tags to your site, you might want to consider removing them.

Heading tags

Heading tags example screenshotHeading tags, a.k.a. h-tags (e.g. <h1>, <h2>, <h3>, etc.) denote heading hierarchy. Traditionally the page’s H1 might mimic the title of a page/blog post, sub-headings below that will be H2s, sub-headings below those will be H3s, and so on.

This very blog post is a good example of proper heading tag etiquette – check the following headings above this section:

  • “Technical SEO Checklist for Developers & Testers (with Cheat Sheet)” (the article’s title) = H1
  • “Technical SEO considerations – the full list” = H2
  • “Important on-page HTML elements” = H3
  • “Heading tags” = H4

As you can see above, each section is contained within the section above it.

It’s not a hard-and-fast rule, but pages should either have one H1 on a page/post, or one H1 per <div> section (in HTML5). You can use multiple H2s, H3s, etc. on a page beyond that. The higher in the hierarchy, the more SEO ‘weight’ they hold, so it makes sense to use them where applicable – at least a H1 on every page and H2s if you can and it makes sense to do so.

URL etiquette

Having URLs spell the name of the page (and ideally containing keywords) is also important for SEO. For example:

is superior to

In addition to SEO, it’s beneficial from a user experience perspective, e.g. when the link is shared as-is on another website, such as a blog, a forum, a social media site, etc., potential visitors can immediately understand what the link is about.

If you’re using parameters in your URLs – whether for tracking purposes, internal search functionality, or something else entirely – then be sure to add them in the URL Parameters section of your site’s Google Search Console account so that Google is aware of them.

Status codes


301 (a.k.a. Moved Permanently) redirects pass on 90-99% of SEO value to the page that they redirect to.

302 (a.k.a. Moved Temporarily) redirects pass on 0% of SEO value – unless they have been in place for a long time.

Other types of redirects – e.g. meta refreshes – may go against search engines’ guidelines, so they are best avoided.

In 99.9% of cases, you will want to use a 301 redirect when redirecting URL X to URL Y. Browsers can treat 301s and 302s differently, so that may factor into your decision.

Learn more about redirects

Not Found

A 404 error (a.k.a. a Page Not Found error) is used when a page does not exist. It is good practice to redirect old/’dead’ URLs – using 301 redirects – to an appropriate page, helping with both SEO and UX.

Be sure to check that your 404 page is actually reporting a 404 status code. If it reports a 200 (a.k.a. OK) code then it is what is known as a ‘soft 404’ – while visitors see a Page Not Found page, search engines will believe it to be a live page and may index it.

Internal linking


Are important landing pages featured in your website’s site-wide menu/navigation structure? Have ‘campaign-only’ pages – e.g. pages only intended to be accessible via Google AdWords, email marketing campaigns, etc. – been excluded from the menu?

HTML sitemap

Also known as a sitemap page, this acts as a standalone page that is intended for human visitors (as opposed to XML sitemaps, which are intended for search engines) to see the pages of your website – it often replicates the site’s menu/navigation or may even contain a link to every single page, especially if it’s only a small website. You often see websites’ HTML sitemaps linked to from their footer.

Google recently updated their Webmaster Guidelines to clarify and encourage this point (source), so it’s certainly worth considering.

In-copy links

Have links been included (where appropriate) in the copy of pages – e.g. within blog content – in order to improve SEO and also to improve the user’s overall experience of the site?


Pagination example screenshot
WordPress and other CMS systems take care of this as standard, but if you’re not on WordPress or running a bespoke solution, you may need to consider it separately. A few years ago, Google introduced rel=”next” and rel=”prev” tags, which indicates the pagination of sections with multiple pages (such as blogs).

Rich snippets and structured data

Rich snippets example screenshot
Structured data – such as – can be used to generate rich snippets in search engines, which means that you can add additional data – such as rating review stars, images, etc. – to your search result beyond the typical title, meta description, etc.

Not all structured data is relevant to all industries/websites, but it is worth checking to see a) if any may be applicable and b) if it’s been implemented correctly using Google’s structured data testing tool.

Learn more about and see example schema types

Image SEO

Image SEO example screenshot
Search engines crawl text, so all things equal, text-heavy pages have a better chance of ranking compared to image-heavy pages – but you can still optimise images for SEO to an extent:

  • File name – Even the file name of an image is an SEO factor, so be sure to give images proper names, such as instead of logo123.jpg. This is especially the case if you are uploading images from digital cameras or smartphones, where it might be a string of numbers/letters or the date that it was taken.
  • Alt attribute – This sometimes appears when hovering the mouse over an image (depending on the browser), if the image doesn’t load, or when visitors use screen readers. Rather than leaving it blank, be sure that it effectively describes the image (and if that description includes a keyword then even better).
  • File size – If images are uploaded at a large size then it can slow down the site, which can affect both SEO and UX. If images only need to be a certain size (e.g. 800px in width) then be sure to upload them at that size instead of their original size (e.g. 2,400px, but it’d resize to 800px anyway). You can also use plugins like WP Smush to bring the file size down further.

Duplicate content checks & fixes

If there is too much duplicate content on a website then it may be discounted – or even penalised – by search engines such as Google. Most duplicate content is accidental and innocent, but Google doesn’t know if you’re trying to game the search engines by trying to get multiple pages to rank when only one is required…

Learn more about duplicate content

Here are some examples:


The rel=”canonical” tag is the most effective way to address duplicate content issues, allowing you to notify search engines that a ‘primary’ version of the URL exists and that search engines should only consider that version of it.

Consider for example the URL /abc, which auto-generates /abc2 and /abc3 as exact duplicates due to a CMS bug. If they all contain the canonical tag referencing /abc, search engines will understand that they are one-and-the-same and attribute the SEO ‘value’ of /abc2 and /abc3 to /abc and only show /abc in its search results.

Learn more about canonical tags

http & https

If a site uses SSL (secure https URLs) then be sure to redirect the standard http URLs to them in each instance, otherwise you will risk having two versions of the site.

As an aside, https gives a slight rankings boost (source)… but it also makes the site slower, which would negate the benefit. With the way that things are at the moment, it makes sense to use https if you genuinely need to – e.g. if user data, payment details, etc. are being processed on parts of the site.

www. & non-www.

If a site is hosted on www. URLs (e.g. then be sure to redirect non-www. URLs to them in each instance, or vice versa if the opposite way around applies (i.e. your site is hosted on URLs).

Internal search

Some internal search functions can cause duplicate content issues – especially on Ecommerce websites. For example, if you have multiple ways to sort content that lists the same set of products then that cause result in duplicate versions of pages.

Blog categories, tags and archives

Similarly, certain blog sections can often generate similar pages, for example if the same posts appear within the same categories or tags. The same applies to archives (e.g. page 2 onwards of a section). One solution is to noindex these sections so that search engines discount them anyway.

Responsive web design & mobile optimisation

Is your website responsive and mobile friendly? In April 2015 Google announced that it would give preference to mobile optimised websites. Google have certain criteria that you need to follow in order to be considered mobile friendly by their standards – and a testing tool to check. It’s worth double-checking because while a website might seem mobile optimised, Google may disagree…

Site speed optimisation

How fast is your site? Site speed is also an SEO factor, with slow-loading websites potentially losing out on rankings. Google’s PageSpeed Insights tool can give recommendations on ways to speed up your website, while WebPagetest’s visual comparison tool is handy to use to compare your website’s speed to that of your competitors.

Social metadata

Social metadata example screenshot
Beyond traditional metadata, websites can display social metadata so that certain titles, descriptions, images, etc. are shown when a page or post is shared on social media websites such as Facebook and Twitter. Here’s a handy guide.

Google Search Console

GSC account example screenshot

Google Search Console (formerly known as Google Webmaster Tools) is free to use and allows you to connect your website to Google in order to use additional functionality, including:

XML sitemaps

Upload your website’s XML sitemaps straight to Google, so that they can get a fair ‘lay of the land’ assessment of your website. Be sure that they only include pages that you actually want indexed (e.g. they do not contain campaign-only pages, such as those intended for Google AdWords use only) and that they are ideally free of any errors or warnings by Google’s standards.


If your site uses a generic top-level domain (TLD) such as a .com, you can choose to target it globally or to a specific country.

Learn more about geo-targeting via GSC

URL parameters

If your site uses URL paramaters, you can configure them here, so that Google can take them into consideration.

Learn more about URL parameters and GSC settings

Blocked resources

A relatively new feature in Google Search Console (source), Google informs you if your site is accidentally blocking images, CSS or JavaScript files via your site’s robots.txt file. Be sure to allow them if you can.

Learn more about blocked resources

Bing (& other) Webmaster Tools

Other search engines – such as Bing and Yandex – also offer their own equivalents of Webmaster Tools. If you’re operating a big website and/or expecting many searchers to come from Bing then it might be worth setting up Bing’s. Yandex is popular in Russia, so that’s also a consideration if you’re expanding into the Russian market.

International SEO considerations

Beyond geo-targeting settings in Google Search Console (see above), you may want to consider the following if your website operates in multiple countries:

  • hreflang – In short, hreflang (full name: rel=”alternate” hreflang=”x”) can be used to inform search engines that different sections of your website are intended for different countries and languages. This is especially handy if you have multiple English versions, such as English UK, English US and English South Africa – Google will then try to show the correct international version to the correct searcher based on their location. It can be implemented via the <head> section of pages or via XML sitemaps. Learn more about hreflang
  • Individual Google Search Console accounts – You can also set up separate search console accounts for domains, sub-domains and sub-folders, depending on how your country websites/sections are configured, which you can then geo-target individually. For example, if your US section is hosted on, you can create a profile for that sub-folder and geo-target it to United States, and so on.

Additional considerations – if the site is being redesigned/migrated

If you are working on a redesign/migration project, there are a few other factors to consider beyond the above:

  • URL redirection of old to new URLs – Perhaps the biggest make-or-break factor of a website redesign project from an SEO perspective is remembering to redirect all the old URLs to the new URLs (if URLs are changing).
  • Google’s Change of Address tool – If the domain is changing as part of the redesign/migration, you can use Google Search Console’s Change of Address tool to notify Google of the change, which will help them to adjust to the changes.

On launch day

This SEO checklist should come in handy whether you’re working on a website that’s yet to launch, or one that’s been live for a while. If you’re working on a new website – or perhaps one that’s being redesigned and/or migrated to a new CMS – then you should also consider the following:

  • Remove noindex & robots.txt disallow from test site – If you were previously building the site on separate domain (e.g. then you will have most likely put measures in place to ensure that the site didn’t accidentally get crawled and indexed by search engines, including adding a meta robots noindex tag on every page and setting a disallow line in robots.txt. When the new site goes live, be sure to remove these so that search engines can then index its pages. However, if you’re planning on keeping the test site live separately for testing purposes then be sure to keep it noindexed/disallowed while allowing the main site to be indexed.
  • Implement redirects (if applicable and if not done previously) – If URLs are changing as part of the redesign then be sure to redirect old URLs to their new counterparts. This should be done on a URL-by-URL basis for best results, not just in terms of SEO but UX as well (e.g. if the About page’s URL is changing from /about to /about-us, be sure to redirect the former to the latter, and so on). Use 301 (a.k.a. Moved Permanently) redirects as they’re the most SEO-friendly.
  • Add/change XML sitemaps – If it’s a brand new site, add its XML sitemap(s) to Google Search Console. If it’s a redesign and its URLs are changing, be sure to remove the old XML sitemap(s) from the old version of the site and add in the new ones from the new site.
  • Migrate Google Analytics & Google Search Console – Be sure to add in the Google Analytics UA code upon launch. You may also need to re-verify Google Search Console depending on how it was verified previously.
  • Fetch as Google – In Google Search Console there is a tool that can be used to ask Google to ‘fetch’ a page, which you can then ask to be submitted to their index. Upon launch, you can consider putting in the homepage and asking Google to index it and its direct links, which should help to speed up the process of Google recognising the changes.

Post-launch checks

Once the site has gone live and the dust has begun to settle, you should consider checking the following:

  • Correct implementation of Google Analytics code – Double-check that the Google Analytics code is properly working. It’s best to do this within a few hours of launch – you don’t want to find out weeks/months later that you’ve not been picking up data, as you’ll have missed out on all that data and have a big data gap in your account.
  • Monitor 404 (Page Not Found) errors – Check that there aren’t any broken links anywhere – especially if you’ve been sorting out redirects in line with a redesign/migration. One of the best ways to check this is via the Crawl Errors section of your Google Search Console account.
  • Monitor Google’s results to see if it’s recognised the changes – Check various brand and keyword searches over time to make sure that search engines are a) picking up the new pages and b) showing them the way that you want them to be shown.

Useful tools, plugins & resources

Various tools and software can be used to help on the technical SEO front:

  • Screaming Frog – Despite the wacky name, if you’re doing technical SEO, Screaming Frog is a godsend. It crawls a site – much in the way that a search engine would – and collects all sorts of data on pages, including page titles, metadata, heading tags, image sizes, directives (e.g. rel=”canonical” tags) and much more.
  • Moz – Their monthly Pro package gives insights into technical SEO improvements and also checks keyword rankings, gives insights into social media and inbound links, and also offers the use of other tools, such as Open Site Explorer (Moz’s link analysis tool). Pretty handy if you’re looking for an overall digital marketing software solution with a focus on SEO.
  • Yoast SEO (WordPress plugin) – If you’re running a WordPress website then this plugin is a must. It gives you the opportunity to edit elements such as page titles and metadata on a per-post/page basis, offers a ‘traffic light’ rating system that indicates how well pages have been optimised, and allows you to make site-wide SEO changes with ease, such as editing the style/format of page titles for categories, tags, etc. It also provides XML sitemaps for you, and gives you direct access to edit your site’s robots.txt and .htaccess files – although it goes without saying that you should obviously be very careful playing around with these…!
  • WP Smush (WordPress plugin) – Mentioned above, WP Smush reduces the file sizes of images without affecting their quality, resulting in a faster website, which in turn will improve its SEO and usability.
  • My ‘sneaky site migrations issues’ post – I recently wrote a blog post containing a few of the more… unusual issues that I’d found when launching redesigned/migrated sites, which you can see here.

I also recommend following these SEO news websites in order to keep on top of any changes that might be going on in the crazy and enlightening world of Google & co.:

  • Search Engine Land – Possibly the most well-known SEO news website.
  • Search Engine Roundtable – Different to SE Land, SE Roundtable tends to focus on news that’s generated around discussions, e.g. news that’s broken via a forum thread or social media update.
  • The SEM Post – A much newer SEO news site, but don’t let you put that off – Jennifer (the editor) is doing an amazing job keeping on top of the ever-evolving world of SEO.

Other (non-technical) considerations

Obviously there’s a lot more to SEO than just the technical and developmental side of things. You could have the mostly perfectly optimised website ever from a technical point of view, but if you’ve not taken the time to consider the following then it may still struggle to rank and compete:

  • Keyword research – Make sure to spend the time researching what your visitors/clients/customers type into search engines in order to find what you’re offering. Different semantics might suggest different types of searchers with different intentions. A good example of this is “web design company” vs. “web development company” – the former might suggest a small brochure website while the latter much suggest a much larger and much more technically-intensive project. If you offer one type of service over the other then make sure that you’ve optimised your site for the right one in order to attract the right types of visitors.
  • On-site copy tweaks – This is perhaps the most well-known aspect of SEO, making sure that keywords are included in pages in all the right places, including page titles, metadata, headings and within the body of the copy itself.
  • Inbound link building – Getting links from other websites that are authoratitive and relevant to yours is extremely important – and yet it often gets overlooked. Some SEOs argue that link building is more important than on-site considerations, and that search engines put more emphasis and importance on it.

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