rudra.js

const generator = createComponentGenerator({ provider: null });
const spec = await generator.generate(input);
// → { tone: 'neutral', headline: 'Goes with your cart', blocks: [ … ] }

verify('Four stars, down from $80', { numerals: ['39'], tags: ['Cookware'] });
// → { ok: false, findings: [ { layer: 'numeral', text: '80' } ] }

Install

npm install @rudra-js/core @rudra-js/react @rudra-js/attested zod@^4.5

Every package lives under the @rudra-js scope. The unscoped rudra-js package on npm belongs to someone else, so keep the @.

You need Node 22.12 or later, and zod 4.5 or later — the public API of @rudra-js/core is zod schemas, so your app and the package have to resolve the same copy. Released under the MIT license.

Installation

In a Next.js app:

import { createComponentGenerator, parseTrackingInput } from '@rudra-js/core';
import { RudraComponent } from '@rudra-js/react';

export default async function Page() {
  const generator = createComponentGenerator({ provider: null });
  const input = parseTrackingInput({
    user: { id: 'shopper-1' },
    context: { surface: 'pdp', currentSku: 'A-1', currentCategory: 'Cookware' },
    candidates: catalog,
  });

  return <RudraComponent spec={await generator.generate(input)} products={input.candidates} />;
}

Without a model — no API key, nothing billed, and a fully supported setting rather than a stub:

const generator = createComponentGenerator({ provider: null });

With a model, when you are ready. Everything above keeps its shape; the model now writes the wording, the layout and the emphasis:

import { createAnthropicProvider } from '@rudra-js/anthropic';

const generator = createComponentGenerator({
  provider: createAnthropicProvider({ apiKey: process.env.ANTHROPIC_API_KEY }),
});

Why rudra.js?

If a language model writes raw HTML, it can put a price you never charged onto your page. rudra-js never lets it write HTML. The model picks a layout, writes a headline and provides the copy — and there is no field for it to invent a price, a product name, an image or a link.

Products are referenced only by SKU, and only from the list you provide
React Server Components read every title, price and image from your catalog
The block ships in the initial HTML, so a crawler that never runs JavaScript still reads it

Packages

rudra-js is four packages, published together at one version.

@rudra-js/core — the contracts and logic that turn one tracking payload into one renderable component specification
@rudra-js/react — renders that specification as React Server Components, with no client JavaScript
@rudra-js/anthropic — talks to the Anthropic API, and is the only package that makes a billed call
@rudra-js/attested — checks model-written copy against the facts a shop stands behind, with no dependencies

You can also run it without a model at all.

Support

Tested on Node 22.12 and the latest Node 22. Node 20 is end of life, so it is neither built nor tested. React 18.2+ or 19 as a peer, and zod 4.5+.

Questions and ideas go in Discussions, bugs in Issues, and vulnerabilities privately.