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Claudius
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Introduction

This content is for v1.x. Switch to the latest version for up-to-date documentation.

Claudius is an open-source, embeddable AI chat widget powered by Claude. You embed a small React-based widget on any website — via a script tag, a web component, or the React component — and it talks to your own Cloudflare Worker, which holds your Anthropic API key and calls Claude.

How it fits together

Section titled “How it fits together”
Visitor's browser                Your Cloudflare account          Anthropic
┌──────────────────┐   POST      ┌──────────────────────┐
│  Claudius widget │ ──────────▶ │  claudius-chat-worker │ ─────▶ Claude API
│  (your website)  │ ◀────────── │  (Hono + KV + D1)     │ ◀─────
└──────────────────┘   JSON      └──────────────────────┘
  • Widget (widget/) — React 18 + TypeScript + Tailwind. Ships as a React component, an IIFE script embed, and a <claudius-chat> web component.
  • Worker (worker/) — Cloudflare Worker built with Hono. Validates input, rate-limits by IP via KV, calls Claude with your system prompt, and optionally records metadata-only analytics to D1.

Your API key never reaches the browser. The widget only knows the worker’s URL; CORS restricts which sites may call it.

What’s in the box

Section titled “What’s in the box”
  • Floating chat bubble with an accessible chat window (WCAG 2.1 AA)
  • Markdown rendering (bold, italic, links) with XSS sanitization
  • Light, dark, and auto themes plus an accentColor brand override
  • Conversation persistence across page navigations (sessionStorage)
  • Request timeout, retry button, and rate-limit-aware error messages
  • Proactive triggers: time on page, scroll depth, exit intent, URL match
  • Bundled English, Spanish, French, and German UI strings with auto-detection
  • KV-based rate limiting (10/min, 50/hr per IP by default)
  • Optional metadata-only analytics to Cloudflare D1
  • Multi-client configuration files with a validation and snippet CLI

Where to go next

Section titled “Where to go next”