Render pipeline

From a title and a brand kit to a cached PNG \u2014 in four stages.

No canvas editor sits between your agent and the output. Every request runs the same deterministic pipeline: resolve, render, convert, cache.

01 · Request

Agent sends structured fields

A title, a theme, a size, and a brandKitId — nothing else to decide. No prompt to iterate on.

Validated against the template's typed schema
Missing fields fall back to brand-kit defaults, never a blank

POST /v1/images

{
  "template": "blog-gradient-v1",
  "title": "How the algorithm ranks posts",
  "size": "1200x630",
  "brandKitId": "brand_9f2c"
}

02 · Resolve

Props merge with the brand kit

Logo, colors, and font resolve from the brand kit — fetched once at save time, never re-fetched per request.

Logo/font fetches are cached and SSRF-guarded
Font buffers pre-loaded per workspace, not per call

resolved_props.json

{
  "accent": "#2F5BFF",
  "font": "Sora-Bold",
  "logo": "cache://brand_9f2c/logo"
}
// resolved from brand_9f2c, not the request

03 · Render

Satori renders JSX → SVG

Each template is a typed JSX component. Satori lays it out and produces SVG — no headless browser, no Chromium process to keep warm.

resvg converts SVG → PNG/WebP
Line balancing and font scaling run automatically on overflow

templates/blog-gradient/index.tsx

export default function Template(props) {
  return (
    &lt;div style={{ background: props.accent }}&gt;
      &lt;h1&gt;{props.title}&lt;/h1&gt;
    &lt;/div&gt;
  );
}

04 · Deliver

Cached, CDN’d, returned

The render is keyed by a hash of the fully-resolved input — same title, template, and brand kit hits cache instantly, even across different agents.

<300ms on a cache hit, globally distributed
Response includes ready-to-embed alt text

200 OK

{
  "url": "cdn.imageclaw.dev/9f2c/a83e.png",
  "width": 1200, "height": 630,
  "cached": true, "ms": 214
}

<1s

cold render

<300ms

cached render

99.9%

availability

P95

<1s API latency

Under the hood

Why it's fast \u2014 and self-hostable.

Satori

No headless browser

Templates render to SVG via layout, not a Chromium instance — dramatically lighter to run and package than Puppeteer-based renderers.

resvg

Fast raster conversion

SVG → PNG/WebP via native Rust bindings, benchmarked against sharp and librsvg for your template complexity.

Cache keys

Hash of resolved input

Template + resolved props + font version — so identical requests from different agents share a cache entry.

Run the whole pipeline yourself.

Render engine, template registry, and CLI are AGPL-licensed. Clone it, point it at your own CDN.

View on GitHub →