oJo — HTML to image and PDF

@ojodotso/mcp-server

oJo turns an HTML template and your JSON data into a PDF or PNG at a hosted link, from the REST API, any MCP client or the editor. This package is oJo's Model Context Protocol server. Live previews are free and need no account; an oJo API key adds hosted PNG and PDF links and reusable templates through the user's own account. Transport is local stdio; the API boundary is HTTP to https://api.ojo.so/v1 only.

Most clients can connect to https://mcp.ojo.so/mcp directly and sign in, without installing anything: see https://ojo.so/docs/mcp-server. This package is the local alternative.

Quick start — no account needed

Point your MCP client at the package. With no API key the server starts in preview-only mode: create_preview_link renders HTML into a live, full-resolution image preview, free and unlimited, with no oJo account.

{

"mcpServers": { "ojo": { "command": "npx", "args": ["-y", "@ojodotso/mcp-server"] } } }

claude mcp add ojo -- npx -y @ojodotso/mcp-server

Adding a key

A key unlocks the permanent PNG or PDF URL — the thing you can put in an email, a social card or an API response — plus reusable templates. Create one at https://ojo.so/dashboard/api and pass it as OJO_API_KEY:

{

"mcpServers": { "ojo": { "command": "npx", "args": ["-y", "@ojodotso/mcp-server"], "env": { "OJO_API_KEY": "sk_..." } } } }

claude mcp add ojo -e OJO_API_KEY=sk_... -- npx -y @ojodotso/mcp-server

Works the same for Claude Desktop, Cursor, and Claude Code.

Tools

Only create_preview_link is registered without an API key; the rest talk to the oJo API, so advertising them keyless would offer tools that can only fail.

The design loop

Iterate with create_preview_link, then render. It returns an https://ojo.so/preview#draft=… URL that renders the draft live in the browser through the same engine as the final PNG, at full resolution. The draft is gzipped into the URL *hash*, so it never reaches a server and nothing is stored — the link is self-contained and shareable with a human reviewer. For a PDF the preview shows the screen rendering, not the page breaks.

Both image tools also accept inspect: true, which returns a 512px-wide downscaled thumbnail alongside the URL. That is a confirmation that the render succeeded, not a design surface — it is too small to judge layout or typography.

Guiding prompt

author_ojo_template — teaches the Handlebars helper catalog, the Template Variables (schema/defaults) vs Modify Payload (per-render data) model, viewport conventions, and the preview-first design loop.

Configuration

• OJO_API_KEY (optional) — your oJo API key. Without it the server runs in preview-only mode; with it the full tool surface is registered.
• OJO_API_BASE_URL (optional) — defaults to https://api.ojo.so/v1.
• OJO_WEB_BASE_URL (optional) — the web app that serves /preview for create_preview_link. Defaults to https://ojo.so; point it at a local http://localhost:3000 when developing against a self-hosted web app.

Develop

pnpm install

pnpm build pnpm test pnpm check