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Widget SDK Overview

The Fyncall Widget SDK lets you embed a customizable chat widget on your website, enabling real-time customer support powered by AI.

Features​

  • Lightweight - Only 17KB initial load with lazy loading for the full chat experience
  • Shadow DOM Isolation - CSS and JavaScript completely isolated from your site
  • Real-Time Messaging - WebSocket-based instant message delivery
  • AI-Powered - Connects to your configured AI agents for automated responses
  • Multi-Platform - Works on desktop and mobile browsers
  • Customizable - Match your brand with colors, positioning, and behavior settings
  • Rich Messages - Product carousels, quick replies, order status cards
  • E-commerce Integration - Shopify cart operations and customer sync

Architecture​

The widget uses a tiered loading architecture for optimal performance:

┌────────────────────────────────────────────────────┐
│  TIER 1: LOADER (2KB)                              │
│  • Fetches tenant configuration                    │
│  • Creates global Fyncall namespace                │
│  • Cache: 5 minutes                                │
└────────────────────────────────────────────────────┘
                        ↓
┌────────────────────────────────────────────────────┐
│  TIER 2: SHIM (15KB)                               │
│  • Web Component: <fyncall-widget>                 │
│  • Closed Shadow DOM for isolation                 │
│  • Cache: 1 year (immutable)                       │
└────────────────────────────────────────────────────┘
                        ↓
┌────────────────────────────────────────────────────┐
│  TIER 3: APP (80KB, lazy loaded on open)           │
│  • Full chat UI and messaging                      │
│  • WebSocket connection                            │
│  • Cache: 1 year (immutable)                       │
└────────────────────────────────────────────────────┘

Performance​

MetricValue
Initial load17KB (gzipped)
Time to launcher< 100ms
Full widget load< 300ms (on open)

Quick Start​

Add this script to your website before the closing </body> tag:

<script async src="https://cdn.fyncall.com/widget/loader.js"
        data-fyncall-widget="fw_your_widget_id"></script>

That's it! The widget will appear as a launcher button in the corner of your page.

Next Steps​