HTTP Endpoints

POST /render

Render HTML to an image.

Request

{
  "html": "<div class=\"flex w-full h-full bg-blue-500\">Hello</div>",
  "width": 1200,
  "height": 630,
  "format": "svg",
  "fonts": []
}

Field	Type	Required	Default	Description
html	string	yes		HTML to render
width	int	no	1200	Canvas width
height	int	no	630	Canvas height
format	string	no	"svg"	"svg", "png", or "jpeg"
quality	int	no	90	JPEG compression quality (1-100). Ignored for SVG/PNG.
fonts	array	no	[]	Custom fonts

Font objects

{
  "name": "Inter",
  "weight": 400,
  "style": "normal",
  "url": "https://example.com/Inter.ttf"
}

Or with base64 data:

{
  "name": "Inter",
  "weight": 400,
  "style": "normal",
  "data": "base64-encoded-font-data"
}

Response

Image bytes with headers:

Header	Value
Content-Type	image/svg+xml, image/png, or image/jpeg
ETag	SHA-256 hash of the input
X-Cache	HIT or MISS
Cache-Control	public, max-age=86400 (hit) or public, max-age=3600 (miss)

POST /render/template

Render a Go html/template with data substitution.

Request

{
  "template": "<div class=\"text-4xl text-white\">{{.Title}}</div>",
  "data": { "Title": "Hello World" },
  "width": 1200,
  "height": 630,
  "format": "svg"
}

Field	Type	Required	Default
template	string	yes
data	object	no	{}
width	int	no	1200
height	int	no	630
format	string	no	"svg"
quality	int	no	90

Response

Same as /render.

GET /health

{"status": "ok"}

GET /metrics

{
  "render_total": 150,
  "render_errors": 2,
  "cache_hits": 98,
  "cache_misses": 52,
  "total_duration_ms": 4200
}

Error responses

All errors return JSON:

{
  "error": "description of what went wrong"
}

Status	Meaning
400	Bad request (missing fields, invalid template, invalid font)
429	Rate limit exceeded
500	Render failed
504	Render timeout

CORS

All endpoints return Access-Control-Allow-Origin: *.

Limits

Limit	Value
Max request body	10 MB
Max fonts per request	5
Max font size	5 MB
Default cache size	64 MB
Default render timeout	10 seconds
Default max elements	1000