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Rendorix

Rendering strategies

Where you render HTML (and when you mint Rendorix URLs) changes ops and caching more than it changes the image pipeline itself. The edge still sees a normal GET; the question is whether those URLs were produced at build time, on each request, or per session on a server you control.

  • Static — SSG / prerender: HTML and image URLs are fixed when you build (or when CI runs). Best when content and allowlists are known ahead of time.
  • SSR — On-demand HTML: you sign and inject URLs per request or per user. Best when pages are personalized or links must stay short-lived.

Both require HMAC (or equivalent) to run in a trusted environment—never in the browser bundle (Usage).

Decision tree

Section titled “Decision tree”
flowchart TB
  q1{Does each visitor need a different set of image URLs?}
  q2{Is all image metadata known when you run build or CI?}
  ssrPath[Use SSR or hybrid]
  staticPath[Use static or prerender]
  q1 -->|no| q2
  q1 -->|yes| ssrPath
  q2 -->|yes| staticPath
  q2 -->|no| ssrPath

Rule of thumb: If the only differences are A/B on copy and image list is the same for everyone, static is simpler. If who is logged in, entitlements, or per-user avatars change the URL set, you need a server in the path for signing (full SSR or a BFF that the static app calls for tokens or signed URLs only).

ConcernLean staticLean SSR
Secret handling (HMAC)In build/CI envIn server runtime env
URL freshness (exp)Rebuild to refreshNew URL every request if needed
HTML cacheabilityVery cacheable at CDNHarder if HTML is per-user
Operational surfaceBuild + deployAlways-on runtime

Shared guidance

Section titled “Shared guidance”
  • Never sign in the client — Use Generating image URLs from a build plugin, server module, or serverless function only.
  • Match exp to your HTML lifecycle — TTL: a static page with a 1-hour signed URL in HTML can break images for anyone who keeps a tab open; static sites often use longer signed TTL and bust caches with deploys or versioned assets.
  • Optional hybrid — A static app can call a small API that returns a signed URL for a key; you still do not put the secret in the client.
  • Framework pointers — Astro (static) and Astro (SSR) when those examples are filled in.

See also

Section titled “See also”