Render HTML/CSS, web pages and saved templates to images and PDFs with HTML/CSS to Image (hcti.io).
HTML/CSS to Image ships in the w6w first-party pack. It declares 12 actions, 2 health checks, and the host runs its code in a sandbox that never sees the credential.
io.w6w.htmlcsstoimageHTML/CSS to Image turns markup into pictures: send HTML and CSS, a public URL, or the values for a saved template, and get back a permanent image URL (PNG, JPG, WebP or PDF) served from a CDN. It is the usual way to generate social cards, receipts, certificates, product graphics and page screenshots from a workflow without running a browser.
This app covers the three ways to create an image (HTML/CSS, URL screenshot, and a saved template, optionally pinned to a version), reading and listing the images an account has made, deleting them, and the template lifecycle: create a template, save a new version of it, list templates and their versions, and remove one. It also reads the account’s image usage by hour, day, month and billing period.
Image creation spends image credits on the vendor’s side, so none of the creation actions is marked retry-safe; use the vendor’s duplicate-detection window (dedupe_duration_s) when a retry could otherwise bill twice.
Three routes to the same 12 actions. The Workflow tab is generated from HTML/CSS to Image's own manifest and carries its real ids, so it is copy-pasteable; the Code and CLI examples are the same call for any action on any app, so every app-specific value in them is a blank you fill in.
image-create-html Render HTML and CSS to an image (PNG, JPG, WebP) or PDF and get its URL.
image-create-template Render a saved template with your values to an image or PDF.
image-create-url Screenshot a public web page to an image (PNG, JPG, WebP) or PDF.
template-create Save an HTML/CSS template with Handlebars variables for later rendering.
template-version-create Save a new version of an existing template; renders without a pinned version use it.
template-versions-list List the saved versions of a template (the way to read one template's HTML/CSS).
A workflow step names the app and the action, and the editor fills in the
connection when you pick one. This is the Step shape from the
workflow spec, carrying HTML/CSS to Image's real ids.
{
"manifestVersion": "2",
"name": "htmlcsstoimage-example",
"steps": [
{
"id": "image-create-html",
"uses": {
"app": "io.w6w.htmlcsstoimage",
"action": "image-create-html",
"connection": "conn_YOUR_CONNECTION_ID"
},
"with": {
"html": "<html>"
}
}
]
}image-create-html image-create-template image-create-url image-get image-list +7 more actions available
Every app-specific value here is a blank you have to fill in. An
app action is reached through the connection that authenticates it, so the
address is a connection id, not the app id — and connections belong to your account,
so a public page cannot know yours. Create one for HTML/CSS to Image, then fill in
the three blanks: conn_YOUR_CONNECTION_ID, the action key, and the
parameters that action declares. The call itself is real — the shape is transcribed
from the studio's own snippet builder, which prints the same kind of blanks — but
nothing in it is specific to HTML/CSS to Image. The Workflow tab is where this app's
real ids are.
npm install @w6w/sdkyarn add @w6w/sdkpnpm add @w6w/sdkdeno add npm:@w6w/sdkimport { W6wClient, isActionRun } from "@w6w/sdk";
// Reads W6W_BASE_URL and W6W_TOKEN from the environment when omitted.
const client = new W6wClient();
const envelope = await client.run({
urn: "conn_YOUR_CONNECTION_ID",
action: "image-create-html",
payload: {
html: "<value>",
// css: "<value>",
// google_fonts: "<value>",
// format: "<value>",
// device_scale: "<value>",
// viewport_width: "<value>",
// viewport_height: "<value>",
// selector: "<value>",
// ms_delay: "<value>",
// max_wait_ms: "<value>",
// color_scheme: "<value>",
// media_type: "<value>",
// timezone: "<value>",
// transparent_background: "<value>",
// render_when_ready: "<value>",
// dedupe_duration_s: "<value>",
// metadata: "<value>",
// pdf_options: "<value>",
},
});
if (isActionRun(envelope)) console.log(envelope.value); npm install -g @w6w/cli w6w run conn_YOUR_CONNECTION_ID --action image-create-html --payload '{"html":"<value>"}' Give an AI agent HTML/CSS to Image — without giving it HTML/CSS to Image's credentials. One MCP endpoint exposes every app, function and workflow the caller is entitled to, as tools it can discover and run. Access is granted per team while we onboard.
One tool call{
"name": "w6w_invoke",
"arguments": {
"ref": "app:io.w6w.htmlcsstoimage#image-create-html",
"input": {
"html": "<html>"
}
}
}
Every tool names its target with a single ref. The
app: form above doesn't name a connection at all — the
host resolves which of the caller's HTML/CSS to Image connections to sign
with, and refuses rather than guesses when the answer is ambiguous.
The token is attached host-side, at the moment of the call. It is never a tool argument, never in the model's context, and never in a transcript — so a prompt injection has nothing to exfiltrate.
Tools are derived per end user from what that person has actually connected and is entitled to — not one shared bot identity carrying the union of everyone's access.
Multi-step work runs on the workflow engine and returns a run handle the agent can poll — retries, branching and state survive the conversation that started them.
HTML/CSS to Image's declared health checks are on the surface too, so an agent can tell "the vendor is down" from "your credential expired" before it burns a retry on either.
The MCP surface is part of the hosted platform. HTML/CSS to Image itself is MIT, and the runtime that executes it is source-available (FSL).
HTML/CSS to Image declares its own checks, so its health is a property of the app rather than something the host guesses at.
Status of the `API` component (hcti.io) on status.htmlcsstoimage.com; the website and dashboard component is reported as detail and never decides the verdict.