I have worked in digital marketing for more than 16 years, and one thing I have learned is that many SEO problems are created before an SEO specialist ever gets involved. Developers make decisions about URLs, site structure, rendering, navigation, redirects, templates, and performance because they are building the product. Those decisions can have a major impact on organic search later, even when SEO was never part of the original development plan.
SEO is often treated as something to add after a website launches. The development team builds the product, everything works, and then marketing is asked to optimize it. By that point, some of the decisions that matter most for search visibility have already been made.
I experienced this while building GamesMom. One of the decisions that created extra work later was our URL structure. We initially organized some content under categories because it seemed like a logical way to structure the site. As the website grew, we decided that individual resources would work better with a flatter URL structure.
A good example is our chess content. The page now lives at https://gamesmom.com/chess-for-kids/, but it previously lived under https://gamesmom.com/brain-games/chess-for-kids/. The new structure made more sense as the site evolved, but changing URL architecture after launch created considerably more work than it would have before launch.
The old URL may already be known by search engines, users, analytics systems, bookmarks, and other websites. Internal links may still point to it, and external websites may have linked to it. A proper migration means handling redirects, updating internal links, checking canonical URLs, updating the sitemap, and monitoring the new URLs after deployment.
There is no universal rule saying flat URLs are better than category based URLs. Both can work. The important thing is to decide what makes sense for the website long term.
Developers often think of URLs as application routes. Once a website is live, however, those routes become public addresses that other systems depend on. I now think about important URLs almost like public APIs. If you don't have a good reason to change them, don't.
This becomes even more important for content heavy websites. A URL structure that works with 20 pages may become very difficult to change when the site has thousands.
Modern frameworks, CMS platforms, automation tools, and AI make it easy to generate hundreds or thousands of pages. The technical ability to create pages quickly doesn't mean every page needs to exist.
Templates are useful for consistency and development efficiency, but they should not replace the work of creating useful content. If ten pages provide almost the same information, changing the title and URL doesn't suddenly make them ten valuable resources.
Before building a system that can generate thousands of URLs, decide what makes an individual page useful and different from the others.
It is much easier to build ten strong pages than to build a thousand pages and later figure out which ones should be rewritten, merged, redirected, or removed.
Internal linking should also be considered during development. When related pages are properly connected, users can discover useful content more easily and search engines can better understand the relationships within the website.
For example, an educational website might connect a multiplication resource with other math activities or connect typing games with typing lessons. Those relationships should make sense to the user rather than existing simply to add links.
Building these relationships into the site's structure from the beginning is much easier than trying to create them after hundreds of pages have already been published.
Modern JavaScript applications can deliver excellent experiences, but developers should understand how important content is rendered and discovered.
If critical content, links, metadata, or structured data depend heavily on client side JavaScript, make sure the implementation works as intended for search engines as well as users.
This doesn't mean avoiding JavaScript. It means understanding which parts of the application matter for search and making sure they are reliably available.