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FeaturesBlockManOSUpdated March 26, 2026

Faster Avatar Loads with CDN Preconnect Hints

Faster Avatar Loads with CDN Preconnect Hints

Release: v1.0.90 · PERF-08

Overview

BlockManOS v1.0.90 introduces preconnect and dns-prefetch resource hints for the three external CDN domains that serve user avatar images. This is a pure performance improvement with no functional behaviour changes.

Background

Authenticated users see a nav-bar avatar on every page load. Those avatars are served from external CDN domains depending on which OAuth provider the user signed in with:

ProviderDomain
Google OAuthlh3.googleusercontent.com
GitHub OAuthavatars.githubusercontent.com
Gravatar (fallback)www.gravatar.com

Prior to this release, the root layout included no connection pre-warming hints for these domains. On first load, the browser had to perform a full DNS lookup → TCP handshake → TLS negotiation before a single byte of avatar data could be fetched. Because avatars are positioned above the fold, this delay is directly user-visible.

What Changed

The root layout (src/app/layout.tsx) now includes an explicit <head> block with both preconnect and dns-prefetch hints for all three domains:

<!-- Google OAuth avatars -->
<link rel="preconnect" href="https://lh3.googleusercontent.com" />
<link rel="dns-prefetch" href="https://lh3.googleusercontent.com" />

<!-- GitHub OAuth avatars -->
<link rel="preconnect" href="https://avatars.githubusercontent.com" />
<link rel="dns-prefetch" href="https://avatars.githubusercontent.com" />

<!-- Gravatar fallback avatars -->
<link rel="preconnect" href="https://www.gravatar.com" />
<link rel="dns-prefetch" href="https://www.gravatar.com" />

Why both preconnect and dns-prefetch?

  • preconnect — Instructs the browser to perform the DNS lookup, TCP handshake, and TLS negotiation as early as possible, before any request for that domain is made. Supported by all modern browsers.
  • dns-prefetch — A lighter fallback that resolves DNS only (no TCP/TLS pre-warm). Used by older browsers that do not support preconnect.

Including both ensures the widest browser coverage for the optimisation.

Expected Impact

MetricBeforeAfter
First avatar connection overhead~150–300 ms (cold)~0 ms (pre-warmed)
AffectsAll authenticated page loads—
ScopeAbove-the-fold nav-bar avatar—

The improvement is most noticeable on first load and after periods where the connection to the CDN has gone cold (e.g. a user returning to a tab after several minutes).

Other Changes in this Release

  • The /api/health route handler was updated to be async in line with Next.js route handler conventions. This is a housekeeping change with no observable effect on the health endpoint's behaviour or response.

Upgrade Notes

  • No migrations required.
  • No new environment variables required.
  • No breaking changes.

This release is a drop-in upgrade.