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Rendorix

Usage

Usage is: given an asset key and the transform you want, produce a signed HTTPS URL the edge will accept. You can do that in two ways:

  1. With @rendorix/client (recommended in Node) — The “Tailwind for images” model: you define presets once (width, height, format, quality—your design tokens for images). In server code, you call img(…, { preset: "hero" }) or add inline w / h / f / q to tweak a preset. The library builds the URL and signature; you do not assemble query params or HMAC by hand. That keeps templates and components focused on names and options, not on crypto details.

  2. Without the library — Implement the same resolve → validate → canonicalize → sign pipeline yourself (e.g. Ruby, Go, or a shell script) using the wire format and signing rules your deployment documents. The edge does not care who signed the URL, only that the bytes match.

The browser always receives a fully formed URL (or srcset list); it never holds the HMAC secret. Framework choice (Astro, Next.js, etc.) only changes where server code runs—see Rendering strategies.

Read Generating image URLs for what the URL means on the wire, then Using presets and Overrides for app-level patterns.

Typical flows

Section titled “Typical flows”
FlowWhere signing runsNotes
Server-rendered page (SSR, API route)Per request or per sessionGood for short signed TTL; no secret in the client.
Static build (SSG, CI)At build timeURLs baked into HTML; rebuild when you need new links or longer-lived cache bust.
Backend job (email, PDF, notifications)When the job runsSame as SSR: only trusted code signs.
Client-only appDoes not sign with the HMAC secretUse a small server or BFF endpoint that returns a fresh signed URL, or pre-signed responses from your API.

All of these assume the browser only ever sees already-signed URLs or opaque tokens your backend exchanges for signed URLs.

Environment-specific behavior

Section titled “Environment-specific behavior”
  • Base URL — Use a config value like RENDORIX_BASE_URL / PUBLIC_RENDORIX_HOST so dev can point at a staging distribution and prod at the live CloudFront hostname or custom domain.
  • Secrets — The HMAC (or signing) key stays in server env, Secrets Manager, or CI secrets—never in NEXT_PUBLIC_* or client bundles.
  • Preset catalogs — dev might allow extra debug presets; prod should use a strict allowlist enforced at the edge (see Presets).
  • Link lifetime — Shorter exp in preview deployments if URLs might leak in PR comments or logs.
Section titled “Links to deep dives”