SEO Programming
SEO programming is the use of code, site architecture, and technical implementation to make a website easier for search engines to crawl, understand, index, and rank.
Start here
- Start with crawlability: internal links, sitemaps, and clean
robots.txt. - Use semantic HTML — heading tags, descriptive links, and proper structure.
- Test JavaScript rendering with Google's tools before launch.
- Monitor Core Web Vitals and fix performance bottlenecks.
- Add structured data for key content types.
Here's what I'd focus on first, and where I've seen people trip up.
What I'd do first
- Make sure your pages are discoverable. Use internal links and submit an XML sitemap. Check that important pages aren't blocked by
robots.txtornoindextags. - Write semantic HTML. Use proper heading hierarchy (
<h1>,<h2>, etc.), descriptive link text, and clean structure. This helps crawlers parse your content. - Test how JavaScript renders. If your site relies on JS to load key content, use Google's URL Inspection Tool or the Mobile-Friendly Test to confirm crawlers see it.
- Optimize for performance. Aim for good Core Web Vitals scores — especially Largest Contentful Paint (LCP) and Cumulative Layout Shift (CLS). Speed matters for both users and rankings.
- Add structured data. Use Schema.org markup for products, articles, FAQs, or events. It helps search engines understand your content and can enable rich results.
Plain-English take
Think of SEO programming like building a house with clear signage. You want the delivery person (Googlebot) to find the front door easily, walk through without tripping, and know exactly what each room is. That means:
- Clear paths — internal links and sitemaps.
- Open doors — no accidental blocks like
noindexorrobots.txtdisallows. - Labels on rooms — semantic HTML and structured data.
- Fast elevators — quick load times and stable layouts.
If you hide the door behind a JavaScript maze or forget to label the kitchen, the delivery person might leave without dropping off your package (i.e., ranking your page).
When it actually matters
- Launching a new site or redesign. Every decision about framework, routing, and content delivery affects crawlability. This is the best time to get it right.
- Adding dynamic content. If you load products, articles, or user-generated content via JavaScript, you need to verify that search engines can render and index it.
- Fixing a traffic drop. Often the culprit is a technical issue — a misconfigured
robots.txt, broken internal links, or a slow server response. - Scaling up. As your site grows, poor architecture (like duplicate URLs or missing canonicals) can snowball into massive indexation problems.
- Competing in a crowded space. When everyone has good content, technical polish can be the tiebreaker that gets you the edge.
What I got wrong
- Blocking important pages by accident. I once set
Disallow: /inrobots.txtduring a staging move and forgot to remove it. Took weeks to notice the traffic drop. - Assuming Google renders JavaScript like a browser. I built a single-page app with critical content loaded via AJAX, but Googlebot couldn't see it. Now I always test with the URL Inspection Tool.
- Ignoring HTML semantics. I used
<div>for everything because it was faster. Headings were just styled text. Google couldn't figure out my page structure. - Forgetting canonicals. I had the same product page accessible via multiple URLs. Without a canonical tag, Google split ranking signals across duplicates.
- Overlooking mobile rendering. I optimized for desktop first, but Google primarily uses the mobile version for indexing. Mobile-friendly testing should be non-negotiable.
Next step
Sources
Primary documentation is linked directly. Anything commercial is marked nofollow.
- Google Search Central: SEO Starter Guide — Primary guidance from Google on crawlability, sitemaps, content accessibility, and SEO basics.
- Google Search Central: Search Essentials — Official Google framework for what helps pages appear in Search and what can prevent indexing.
- Google Search Central: Core Web Vitals — Official source for performance metrics that affect user experience and are relevant to technical SEO.
- Google Search Central: JavaScript SEO — Best reference for how Google handles JavaScript-rendered content.
- Google Search Central: Structured data — Official documentation on structured data implementation and eligibility.
Notes from Callum Bennett.