2025 SEO Checklist for Custom Web Applications (Next.js, SaaS & Beyond)

2025 SEO Checklist for Custom Web Applications (Next.js, SaaS & Beyond)

Custom web applications aren't like static sites or CMS-driven blogs. They're built on frameworks like Next.js, React, and modern SaaS stacks, which introduce unique SEO challenges: dynamic routing, hydration issues, Core Web Vitals performance, and structured data complexity.

If you're building or running a Next.js app, SaaS product, or enterprise web portal, this checklist gives you the step-by-step actions you need in 2025 to stay visible in both traditional search engines and AI-driven experiences like Google's SGE, Perplexity, and Claude. These strategies align with the broader SEO trends shaping 2025.

For AI-specific optimization strategies, make sure you also read our companion post: AI Search Optimization 2025.

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1. Core Web Vitals (Updated Benchmarks for 2025)

Google's ranking systems continue to use Core Web Vitals as key UX signals. Since March 2024, INP (Interaction to Next Paint) officially replaced FID. Your app must meet these thresholds:

• LCP (Largest Contentful Paint): < 2.5s
• CLS (Cumulative Layout Shift): < 0.1
• INP (Interaction to Next Paint): < 200ms

How to Optimize in Next.js

• Use the next/image component with AVIF/WEBP formats and priority for hero images.
• Preload fonts with <link rel="preload" as="font">.
• Use Vercel Edge Caching or Cloudflare CDN for global delivery.
• Lazy-load offscreen components.
• Prefetch routes with the <Link> component.

In our work on the Travel With Aspect Miami Luxury Villas page, fixing LCP and CLS by optimizing hero images/videos and reducing layout shift directly improved rankings after a period of decline.

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2. Technical Foundations for Next.js & SaaS

Routing & Rendering

• Use App Router with SSR (server-side rendering) or SSG (static site generation) for critical pages.
• Don't leave core pages like /pricing, /features, or /docs client-only rendered.

Canonicalization

Always specify a canonical tag to avoid duplicate indexing:

// app/layout.tsx
import { Metadata } from "next";

export const metadata: Metadata = {
  title: "My SaaS App",
  alternates: {
    canonical: "https://www.example.com/",
  },
};

Robots.txt

Ensure your robots.txt allows crawling of key pages and blocks staging or admin areas.

// app/robots.ts
import type { MetadataRoute } from "next";

export default function robots(): MetadataRoute.Robots {
  return {
    rules: [
      {
        userAgent: "*",
        allow: "/",
        disallow: ["/api/"],
      },
      {
        userAgent: [
          "GPTBot",
          "PerplexityBot",
          "ClaudeBot",
          "Google-Extended",
          "BingAI",
        ],
        allow: "/",
      },
    ],
    sitemap: "https://www.example.com/sitemap.xml",
  };
}

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3. XML Sitemaps & Indexing

Search engines and AI systems depend on clean sitemaps.

Checklist

• Generate with next-sitemap.
• Ensure canonical URLs only (no www vs non-www duplicates).
• Add <lastmod> with YYYY-MM-DD.
• Submit the sitemap in Google Search Console.

Example config:

// next-sitemap.config.js
module.exports = {
  siteUrl: "https://www.example.com",
  generateRobotsTxt: true,
  changefreq: "weekly",
  priority: 0.7,
  sitemapSize: 5000,
};

If your sitemap contains legacy or duplicate URLs, it can confuse Google. We saw this when auditing Travel With Aspect's site — cleaning it up reduced "Indexed, not submitted in sitemap" errors.

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4. Schema Markup Essentials

Schema helps both Google and AI crawlers understand your content. For apps and SaaS sites, these are critical:

• Organization — your company identity.
• SoftwareApplication / Product — your SaaS or tool.
• FAQPage — for docs or support sections.
• Article / BlogPosting — for blog posts.

Example (SoftwareApplication):

{
  "@context": "https://schema.org",
  "@type": "SoftwareApplication",
  "name": "QuickETL",
  "operatingSystem": "Web",
  "applicationCategory": "BusinessApplication",
  "offers": {
    "@type": "Offer",
    "price": "99.00",
    "priceCurrency": "USD"
  }
}

When paired with FAQ schema, this also boosts inclusion in AI-generated overviews.

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5. Internal Linking Strategy

• Top pages: Link frequently to /services/seo-optimization, /portfolio, and /blog.
• Use descriptive anchor text: "Next.js SEO checklist" instead of "click here."
• Topic clusters:
  • SEO for Web Apps: This checklist → AI Search Optimization 2025 → Case studies.
  • ETL & Automation: Technical guides → QuickETL examples → Case studies.

Strong linking between technical posts and conversion pages prevents traffic leaks. If you're worried about conversion loss, see our guide: Is Your Website Costing You Customers?.

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6. Security & Accessibility

• Enforce HTTPS with HSTS headers.
• Add security headers: Content-Security-Policy, X-Frame-Options, and Referrer-Policy.
• Use Cloudflare Turnstile for spam protection.
• Provide alt text for all images.
• Follow WCAG 2.2 accessibility standards.

Accessibility improvements often translate into better SEO signals (reduced bounce rate, improved engagement).

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7. AI Search Discoverability

AI-driven search engines are now a major traffic source. To be AI-discoverable:

• Write concise, factual answers (<50 words) for FAQs.
• Use structured data (FAQPage, HowTo).
• Make headings scannable and content modular.
• Monitor server logs for AI bots like GPTBot and PerplexityBot.

For the advanced playbook, see AI Search Optimization 2025.

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8. Measurement & Tracking

• Google Search Console: Track indexing, query impressions, and AI Overview visibility.
• GA4: Monitor engagement, conversions, and scroll depth.
• Core Web Vitals Reports: Use CrUX and Search Console monthly.
• Log analysis: Confirm crawl frequency for both Googlebot and AI bots.

Cadence

• Weekly: Ship updates and track fixes.
• Monthly: Audit Core Web Vitals and AI search visibility.
• Quarterly: Refresh high-value pages and conduct comprehensive SEO audits to identify new opportunities.

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Final Thoughts

SEO in 2025 requires a dual focus:

1. Technical foundations like Core Web Vitals, clean sitemaps, and schema.
2. AI discoverability for emerging search platforms.

By following this checklist, your custom web app will:

• Rank higher in Google.
• Earn inclusion in AI overviews.
• Convert visitors into leads more effectively.

Use this checklist as your baseline and pair it with our AI Search Optimization 2025 guide to future-proof your site.

And if you'd rather not go it alone, our SEO Optimization Services help businesses improve search rankings, capture more qualified leads, and turn their websites into growth engines.