# TTFB is configured to meet the 800ms threshold

- **Pattern:** `ab-001784` (`marketing-page-speed.core-web-vitals.ttfb-threshold`)
- **Severity:** high
- **Lifecycle:** active
- **Last modified:** 2026-04-18
- **Canonical URL:** https://auditbuffet.com/patterns/ab-001784
- **License:** CC-BY-4.0 — attribute to AuditBuffet Pattern Catalog (https://auditbuffet.com/patterns/ab-001784)

## Why it matters

Time to First Byte is the foundation every other performance metric builds on — a slow TTFB adds its full penalty to LCP, FCP, and INP simultaneously. ISO-25010 time-behaviour defines server response time as a core quality characteristic, and marketing pages violate it most commonly by using full server-side rendering with no caching on a single-region origin. A user in London hitting a server in us-east-1 with no CDN experiences 150–250ms of raw network latency before the server even starts generating HTML, plus server processing time. TTFB above 800ms is a direct cause of poor Core Web Vitals scores across all categories and signals to Google's Page Experience system that the server infrastructure is underperforming for users.

## Severity rationale

High because TTFB directly sets a floor under LCP, FCP, and INP — a slow origin server makes all downstream performance optimisations less effective regardless of their quality.

## Remediation

Switch marketing pages to static generation so they're served from CDN edge in under 50ms. Remove `force-dynamic` from any marketing route and let Next.js use its default static rendering.

```ts
// app/(marketing)/page.tsx — static by default, no changes needed
export default function HomePage() {
  return <MarketingPage />
}

// If the page needs fresh CMS content, use ISR instead of full SSR
export const revalidate = 3600 // regenerate at most once per hour
export default async function LandingPage() {
  const content = await fetchCMSContent()
  return <LandingPage content={content} />
}
```

Deploy to Vercel, Netlify, or Cloudflare Pages — these platforms serve ISR-cached HTML from edge nodes globally without any additional CDN configuration.

## Detection

- **ID:** `ttfb-threshold`
- **Severity:** `high`
- **What to look for:** Time to First Byte (TTFB) is the time from the browser sending a request to receiving the first byte of the response. For marketing pages, TTFB > 800ms is a red flag. TTFB is determined by: (1) rendering strategy — SSG/static is served from CDN edge (<50ms), SSR with no cache adds server processing time, (2) CDN configuration — is there a CDN in front of the origin? (3) cold start latency — serverless functions have cold start penalties of 200-500ms. Examine next.config.* for `output: 'export'` or `revalidate` settings, vercel.json for CDN config, and rendering strategy of the homepage and key landing pages. Count all instances found and enumerate each.
- **Pass criteria:** Marketing pages (homepage, landing pages) are statically generated (SSG, `output: 'export'`, or ISR with cache hit) so they're served from CDN edge. OR hosting is Vercel/Netlify/Cloudflare Pages which serve static assets globally by default. TTFB budget ≤ 800ms is achievable. At least 1 implementation must be confirmed.
- **Fail criteria:** All marketing pages use full SSR (`force-dynamic` or equivalent) with no caching, served from a single-region origin with no CDN. Cold starts add >500ms penalty. TTFB would predictably exceed 800ms on first request.
- **Skip (N/A) when:** No server-side rendering — project is purely static HTML. TTFB is CDN-only and not configurable in code.
- **Detail on fail:** `"Homepage uses force-dynamic SSR with no cache headers. Hosting is a single-region VPS with no CDN configured. TTFB will predictably exceed 800ms for non-local users."`
- **Remediation:** Use static generation for marketing pages:

  ```ts
  // Next.js App Router — static by default for pages with no dynamic data
  // app/(marketing)/page.tsx
  export default function HomePage() {
    return <HomePage /> // statically rendered at build time
  }

  // ISR — regenerate periodically, serve from cache
  export const revalidate = 3600 // revalidate every hour
  export default async function LandingPage() {
    const content = await fetchCMSContent()
    return <LandingPage content={content} />
  }
  ```

  Deploy to Vercel, Netlify, or Cloudflare Pages — they serve static assets from global edge networks without extra CDN configuration.

## External references

- iso-25010 performance-efficiency.time-behaviour

Taxons: performance

HTML version: https://auditbuffet.com/patterns/ab-001784