Imported from JantonioFC/skillsbank (skills/chat-widget/SKILL.md). Install upstream with npx skills add JantonioFC/skillsbank --skill chat-widget. Copyright stays with the author (MIT).

Live Support Chat Widget

Build a real-time support chat system with a floating widget for users and an admin dashboard for support staff.

When to Use This Skill

Use when the user wants to:

Add a live chat widget to their app
Build customer support chat functionality
Create real-time messaging between users and admins
Add an in-app support channel

Architecture Overview

┌─────────────────────────────────────────────────────────────────┐
│                        FRONTEND                                 │
├─────────────────────────────┬───────────────────────────────────┤
│   User Widget               │   Admin Dashboard                 │
│   - Floating chat button    │   - Chat list (active/archived)   │
│   - Message panel           │   - Conversation view             │
│   - Unread badge            │   - Archive/restore controls      │
│   - Connection indicator    │   - User info display             │
└─────────────┬───────────────┴───────────────┬───────────────────┘
              │                               │
              │     WebSocket + REST API      │
              ▼                               ▼
┌─────────────────────────────────────────────────────────────────┐
│                        BACKEND                                  │
├─────────────────────────────────────────────────────────────────┤
│   Channels                  │   Controllers                     │
│   - ChatChannel (per chat)  │   - User: get/create chat         │
│   - AdminChannel (global)   │   - Admin: list, view, archive    │
├─────────────────────────────┼───────────────────────────────────┤
│   Models                    │   Jobs                            │
│   - Chat (1 per user)       │   - Email notification (delayed)  │
│   - Message (many per chat) │                                   │
└─────────────────────────────────────────────────────────────────┘

Implementation Guide

Step 1: Data Models

Create two tables: support_chats and support_messages.

support_chats

id              - primary key (UUID recommended)
user_id         - foreign key to users (UNIQUE - one chat per user)
last_message_at - timestamp (for sorting chats by recency)
admin_viewed_at - timestamp (tracks when admin last viewed)
archived_at     - timestamp (null = active, set = archived)
created_at
updated_at

support_messages

id              - primary key (UUID recommended)
chat_id         - foreign key to support_chats
content         - text (required)
sender_type     - enum: 'user' | 'admin'
read_at         - timestamp (null = unread)
created_at
updated_at

Key indexes:

support_chats.user_id (unique)
support_chats.last_message_at (for sorting)
support_chats.archived_at (for filtering)
support_messages.chat_id
support_messages.(chat_id, created_at) (composite, for ordering)

Model relationships:

User has_one SupportChat
SupportChat belongs_to User
SupportChat has_many SupportMessages
SupportMessage belongs_to SupportChat

Model methods to implement:

Chat model:

function touch_last_message()
  update last_message_at = now()

function unread_for_admin?()
  return exists message where sender_type = 'user'
    and created_at > admin_viewed_at

function mark_viewed_by_admin()
  update admin_viewed_at = now()

function archive()
  update archived_at = now()

function unarchive()
  update archived_at = null

function archived?()
  return archived_at != null

Message model:

after_create:
  chat.touch_last_message()
  if sender_type == 'user' and chat.archived?:
    chat.unarchive()  // Auto-reactivate on new user message

after_create_commit:
  broadcast_to_chat_channel(message_data)
  if sender_type == 'user':
    broadcast_to_admin_notification_channel(message_data, chat_info)
  if sender_type == 'admin':
    schedule_email_notification(delay: 5.minutes)

Step 2: API Endpoints

User-facing:

GET  /support_chat       - Get or create user's chat with messages
PATCH /support_chat/mark_read - Mark admin messages as read

Admin-facing:

GET  /admin/chats              - List chats (query: archived=true/false)
GET  /admin/chats/:id          - Get chat with messages
POST /admin/chats/:id/archive  - Archive chat
POST /admin/chats/:id/unarchive - Restore chat

Controller logic:

User GET /support_chat:

function show()
  chat = current_user.support_chat || create_chat(user: current_user)
  return {
    id: chat.id,
    messages: chat.messages.map(m => serialize_message(m))
  }

Admin GET /admin/chats:

function index()
  chats = SupportChat
    .where(archived_at: params.archived ? not_null : null)
    .includes(:user, :messages)
    .order(last_message_at: desc)

  return chats.map(c => {
    id: c.id,
    user_email: c.user.email,
    last_message_preview: c.messages.last?.content.truncate(100),
    last_message_sender: c.messages.last?.sender_type,
    message_count: c.messages.count,
    unread: c.unread_for_admin?,
    archived: c.archived?
  })

Step 3: WebSocket Channels

Create two channels for real-time communication.

ChatChannel (specific to each chat):

class ChatChannel
  on_subscribe(chat_id):
    chat = find_chat(chat_id)
    if not authorized(chat):
      reject()
      return
    stream_from "support_chat:#{chat_id}"

  function authorized(chat):
    return chat.user_id == current_user.id OR current_user.is_admin

  action send_message(content):
    if content.blank: return
    sender_type = current_user.is_admin ? 'admin' : 'user'
    chat.messages.create(content: content, sender_type: sender_type)

AdminNotificationChannel (global for all admins):

class AdminNotificationChannel
  on_subscribe:
    if not current_user.is_admin:
      reject()
      return
    stream_from "admin_support_notifications"

Broadcasting (from Message model):

function broadcast_message():
  message_data = {
    id: id,
    content: content,
    sender_type: sender_type,
    read_at: read_at,
    created_at: created_at
  }

  // Broadcast to chat subscribers (user + any viewing admins)
  broadcast("support_chat:#{chat.id}", {
    type: "new_message",
    message: message_data
  })

  // Notify all admins when user sends message
  if sender_type == 'user':
    broadcast("admin_support_notifications", {
      type: "new_user_message",
      chat_id: chat.id,
      user_email: chat.user.email,
      message: message_data
    })

Step 4: Frontend - User Widget

Create a floating chat widget with these components:

Component structure:

ChatWidget (root container)
├── ChatButton (fixed position, bottom-right)
│   ├── Icon (message bubble when closed, X when open)
│   └── UnreadBadge (shows count, caps at "9+")
└── ChatPanel (slides up when open)
    ├── Header (title + connection status dot)
    ├── MessageList (scrollable)
    │   └── MessageBubble (styled by sender_type)
    └── InputArea
        ├── Textarea (auto-expanding)
        └── SendButton

State management hook:

function useSupportChat():
  state:
    chat: Chat | null
    connected: boolean
    loading: boolean

  refs:
    consumer: WebSocketConsumer
    subscription: ChannelSubscription
    seenMessageIds: Set<string>  // For deduplication

  on_mount:
    fetch('/support_chat')
      .then(data => {
        chat = data
        seenMessageIds.addAll(data.messages.map(m => m.id))
      })

  when chat.id changes:
    subscription = consumer.subscribe('ChatChannel', { chat_id: chat.id })
    subscription.on_received(data => {
      if data.type == 'new_message':
        if seenMessageIds.has(data.message.id): return  // Dedupe
        seenMessageIds.add(data.message.id)
        chat.messages.push(data.message)
        if data.message.sender_type == 'admin':
          play_notification_sound()
    })
    subscription.on_connected(() => connected = true)
    subscription.on_disconnected(() => connected = false)

  on_unmount:
    subscription.unsubscribe()

  function sendMessage(content):
    subscription.perform('send_message', { content: content.trim() })

  function markAsRead():
    fetch('/support_chat/mark_read', { method: 'PATCH' })
    // Update local state to mark admin messages as read

  return { chat, connected, loading, sendMessage, markAsRead }

Widget behavior:

Show floating button at bottom-right corner (fixed position)
Display unread count badge (count messages where sender_type='admin' and read_at=null)
Toggle panel open/closed on button click
Auto-call markAsRead() when panel opens
Auto-scroll to bottom when new messages arrive
Show connection status indicator (green dot = connected)
Keyboard: Enter to send, Shift+Enter for newline

Message styling:

User messages: right-aligned, primary color background
Admin messages: left-aligned, secondary/muted background
Show timestamp on each message

Step 5: Frontend - Admin Dashboard

Create two pages: chat list and chat detail.

Chat List Page:

Header: "Support Chats"
Tabs: [Active] [Archived]

Chat cards (sorted by last_message_at desc):
┌─────────────────────────────────────────┐
│ [Unread indicator] user@example.com     │
│ Last message preview text...            │
│ 5 messages · 2 minutes ago              │
└─────────────────────────────────────────┘

Features:

Tab filtering (active vs archived)
Unread indicator (highlight border or badge)
Click to navigate to detail
Show "You: " prefix if last message was from admin

Chat Detail Page:

Header: user@example.com [Archive/Restore button]
Back link

Messages (grouped by date):
──── Monday, January 29 ────
[User bubble]  Message content
               10:30 AM

          [Admin bubble] Reply content
                         10:35 AM

Input area (same as widget)

Features:

Group messages by date with dividers
User messages left, admin messages right (opposite of user widget)
Show sender label ("You" for admin, user email/name for user)
Archive/restore toggle button
Same WebSocket subscription as user widget for real-time updates
Call mark_viewed_by_admin() when page loads (server-side)

Step 6: Email Notifications

Send email to user when admin replies and user hasn't seen it.

Job/worker:

class SupportReplyNotificationJob
  perform(message):
    if message.sender_type != 'admin': return
    if message.read_at != null: return  // Already read, skip

    send_email(
      to: message.chat.user.email,
      subject: "New reply from Support",
      body: "You have a new message from our support team..."
    )

Scheduling:

Schedule job with 5-minute delay when admin sends message
This gives user time to see message in-app before email
Job checks if still unread before sending

Step 7: TypeScript Types

interface SupportMessage {
  id: string
  content: string
  sender_type: 'user' | 'admin'
  read_at: string | null  // ISO8601
  created_at: string      // ISO8601
}

interface SupportChat {
  id: string
  messages: SupportMessage[]
}

interface SupportChatListItem {
  id: string
  user_id: string
  user_email: string
  last_message_at: string | null
  last_message_preview: string | null
  last_message_sender: 'user' | 'admin' | null
  message_count: number
  unread: boolean
  archived: boolean
}

interface AdminSupportChat {
  id: string
  user_id: string
  user_email: string
  archived: boolean
  messages: SupportMessage[]
}

// WebSocket message types
interface ChatChannelMessage {
  type: 'new_message'
  message: SupportMessage
}

interface AdminNotificationMessage {
  type: 'new_user_message'
  chat_id: string
  user_email: string
  message: SupportMessage
}

Key Design Decisions

One chat per user - Simplifies UX, user always has same conversation history
Soft-delete via archiving - Preserves history, allows restore
Auto-unarchive - When user sends message to archived chat, reactivate it
Delayed email notifications - 5 min delay prevents spam for rapid replies
Message deduplication - Track seen IDs to prevent duplicates from send + broadcast echo
Separate admin channel - Allows future features like global unread count, desktop notifications

Testing Checklist

After implementation:

Common Pitfalls

Forgetting deduplication - Messages sent by current user echo back via broadcast
Race conditions on read status - Use database transactions
WebSocket auth - Verify user can access the specific chat
Stale connection status - Handle reconnection gracefully
Missing indexes - Add composite index on (chat_id, created_at)
Email timing - Use background job, not synchronous send

Framework-Specific Guidance

Ruby on Rails

Models:

# app/models/support_chat.rb
class SupportChat < ApplicationRecord
  belongs_to :user
  has_many :support_messages, dependent: :destroy

  scope :active, -> { where(archived_at: nil) }
  scope :archived, -> { where.not(archived_at: nil) }
  scope :recent_first, -> { order(last_message_at: :desc) }

  def touch_last_message
    update_column(:last_message_at, Time.current)
  end

  def unread_for_admin?
    support_messages.where(sender_type: :user)
      .where("created_at > ?", admin_viewed_at || Time.at(0)).exists?
  end

  def archive!
    update_column(:archived_at, Time.current)
  end

  def unarchive!
    update_column(:archived_at, nil)
  end
end

# app/models/support_message.rb
class SupportMessage < ApplicationRecord
  belongs_to :support_chat
  enum :sender_type, { user: 0, admin: 1 }
  validates :content, presence: true

  after_create :update_chat_timestamp
  after_create :auto_unarchive, if: :user?
  after_create_commit :broadcast_message
  after_create_commit :schedule_notification, if: :admin?

  private

  def broadcast_message
    ActionCable.server.broadcast("support_chat:#{support_chat_id}", {
      type: "new_message",
      message: { id:, content:, sender_type:, read_at:, created_at: }
    })
  end

  def schedule_notification
    SupportReplyNotificationJob.set(wait: 5.minutes).perform_later(self)
  end
end

Channel:

# app/channels/support_chat_channel.rb
class SupportChatChannel < ApplicationCable::Channel
  def subscribed
    @chat = SupportChat.find(params[:chat_id])
    reject unless @chat.user_id == current_user.id || current_user.admin?
    stream_from "support_chat:#{@chat.id}"
  end

  def send_message(data)
    @chat.support_messages.create!(
      content: data["content"],
      sender_type: current_user.admin? ? :admin : :user
    )
  end
end

Migration:

create_table :support_chats, id: :uuid do |t|
  t.references :user, type: :uuid, null: false, foreign_key: true, index: { unique: true }
  t.datetime :last_message_at
  t.datetime :admin_viewed_at
  t.datetime :archived_at
  t.timestamps
end

create_table :support_messages, id: :uuid do |t|
  t.references :support_chat, type: :uuid, null: false, foreign_key: true
  t.text :content, null: false
  t.integer :sender_type, default: 0
  t.datetime :read_at
  t.timestamps
end
add_index :support_messages, [:support_chat_id, :created_at]

React (with any backend)

Hook:

// hooks/useSupportChat.ts
import { useEffect, useState, useRef, useCallback } from 'react'

export function useSupportChat(websocketUrl: string) {
  const [chat, setChat] = useState<Chat | null>(null)
  const [connected, setConnected] = useState(false)
  const wsRef = useRef<WebSocket | null>(null)
  const seenIds = useRef(new Set<string>())

  useEffect(() => {
    fetch('/api/support_chat').then(r => r.json()).then(data => {
      setChat(data)
      data.messages.forEach((m: Message) => seenIds.current.add(m.id))
    })
  }, [])

  useEffect(() => {
    if (!chat?.id) return
    const ws = new WebSocket(`${websocketUrl}?chat_id=${chat.id}`)
    wsRef.current = ws

    ws.onopen = () => setConnected(true)
    ws.onclose = () => setConnected(false)
    ws.onmessage = (event) => {
      const data = JSON.parse(event.data)
      if (data.type === 'new_message' && !seenIds.current.has(data.message.id)) {
        seenIds.current.add(data.message.id)
        setChat(prev => prev ? { ...prev, messages: [...prev.messages, data.message] } : prev)
      }
    }
    return () => ws.close()
  }, [chat?.id])

  const sendMessage = useCallback((content: string) => {
    wsRef.current?.send(JSON.stringify({ action: 'send_message', content }))
  }, [])

  return { chat, connected, sendMessage }
}

Widget Component:

// components/ChatWidget.tsx
export function ChatWidget() {
  const [isOpen, setIsOpen] = useState(false)
  const { chat, connected, sendMessage } = useSupportChat('/ws/chat')
  const [input, setInput] = useState('')
  const messagesEndRef = useRef<HTMLDivElement>(null)

  const unreadCount = chat?.messages.filter(
    m => m.sender_type === 'admin' && !m.read_at
  ).length ?? 0

  useEffect(() => {
    messagesEndRef.current?.scrollIntoView({ behavior: 'smooth' })
  }, [chat?.messages])

  const handleSend = () => {
    if (!input.trim()) return
    sendMessage(input.trim())
    setInput('')
  }

  return (
    <div className="fixed bottom-4 right-4 z-50">
      {isOpen ? (
        <div className="w-80 h-96 bg-white rounded-lg shadow-xl flex flex-col">
          <header className="p-3 border-b flex justify-between items-center">
            <span>Support Chat</span>
            <span className={`w-2 h-2 rounded-full ${connected ? 'bg-green-500' : 'bg-gray-400'}`} />
          </header>
          <div className="flex-1 overflow-y-auto p-3 space-y-2">
            {chat?.messages.map(m => (
              <div key={m.id} className={`p-2 rounded ${m.sender_type === 'user' ? 'bg-blue-100 ml-auto' : 'bg-gray-100'}`}>
                {m.content}
              </div>
            ))}
            <div ref={messagesEndRef} />
          </div>
          <div className="p-3 border-t flex gap-2">
            <input value={input} onChange={e => setInput(e.target.value)}
              onKeyDown={e => e.key === 'Enter' && !e.shiftKey && handleSend()}
              className="flex-1 border rounded px-2" placeholder="Type a message..." />
            <button onClick={handleSend} className="px-3 py-1 bg-blue-500 text-white rounded">Send</button>
          </div>
        </div>
      ) : (
        <button onClick={() => setIsOpen(true)} className="w-14 h-14 bg-blue-500 rounded-full text-white relative">
          💬
          {unreadCount > 0 && (
            <span className="absolute -top-1 -right-1 bg-red-500 text-xs w-5 h-5 rounded-full flex items-center justify-center">
              {unreadCount > 9 ? '9+' : unreadCount}
            </span>
          )}
        </button>
      )}
    </div>
  )
}

Next.js (App Router)

API Route:

// app/api/support-chat/route.ts
import { getServerSession } from 'next-auth'
import { prisma } from '@/lib/prisma'

export async function GET() {
  const session = await getServerSession()
  if (!session?.user) return Response.json({ error: 'Unauthorized' }, { status: 401 })

  let chat = await prisma.supportChat.findUnique({
    where: { userId: session.user.id },
    include: { messages: { orderBy: { createdAt: 'asc' } } }
  })

  if (!chat) {
    chat = await prisma.supportChat.create({
      data: { userId: session.user.id },
      include: { messages: true }
    })
  }

  return Response.json(chat)
}

WebSocket with Pusher/Ably (serverless-friendly):

// For serverless, use Pusher, Ably, or similar
import Pusher from 'pusher'
const pusher = new Pusher({ appId, key, secret, cluster })

// When message is created:
await pusher.trigger(`support-chat-${chatId}`, 'new-message', messageData)

// Client-side with pusher-js:
const channel = pusher.subscribe(`support-chat-${chatId}`)
channel.bind('new-message', (data) => { /* update state */ })

PHP/Laravel

Models:

// app/Models/SupportChat.php
class SupportChat extends Model
{
    protected $casts = ['last_message_at' => 'datetime', 'archived_at' => 'datetime'];

    public function user() { return $this->belongsTo(User::class); }
    public function messages() { return $this->hasMany(SupportMessage::class); }

    public function scopeActive($query) { return $query->whereNull('archived_at'); }
    public function scopeArchived($query) { return $query->whereNotNull('archived_at'); }

    public function isUnreadForAdmin(): bool {
        return $this->messages()
            ->where('sender_type', 'user')
            ->where('created_at', '>', $this->admin_viewed_at ?? '1970-01-01')
            ->exists();
    }
}

// app/Models/SupportMessage.php
class SupportMessage extends Model
{
    protected static function booted() {
        static::created(function ($message) {
            $message->supportChat->update(['last_message_at' => now()]);
            broadcast(new NewSupportMessage($message))->toOthers();

            if ($message->sender_type === 'admin') {
                SendSupportReplyNotification::dispatch($message)->delay(now()->addMinutes(5));
            }
        });
    }
}

Broadcasting Event:

// app/Events/NewSupportMessage.php
class NewSupportMessage implements ShouldBroadcast
{
    public function __construct(public SupportMessage $message) {}

    public function broadcastOn() {
        return new PrivateChannel('support-chat.' . $this->message->support_chat_id);
    }

    public function broadcastAs() { return 'new-message'; }
}

Vue.js

Composable:

// composables/useSupportChat.ts
import { ref, onMounted, onUnmounted } from 'vue'

export function useSupportChat() {
  const chat = ref<Chat | null>(null)
  const connected = ref(false)
  let ws: WebSocket | null = null
  const seenIds = new Set<string>()

  onMounted(async () => {
    const res = await fetch('/api/support-chat')
    chat.value = await res.json()
    chat.value?.messages.forEach(m => seenIds.add(m.id))

    ws = new WebSocket(`/ws/chat?id=${chat.value?.id}`)
    ws.onopen = () => connected.value = true
    ws.onclose = () => connected.value = false
    ws.onmessage = (e) => {
      const data = JSON.parse(e.data)
      if (data.type === 'new_message' && !seenIds.has(data.message.id)) {
        seenIds.add(data.message.id)
        chat.value?.messages.push(data.message)
      }
    }
  })

  onUnmounted(() => ws?.close())

  const sendMessage = (content: string) => {
    ws?.send(JSON.stringify({ action: 'send_message', content }))
  }

  return { chat, connected, sendMessage }
}

Database Recommendations

PostgreSQL (Recommended)

Use UUID primary keys for security (non-guessable IDs)
Use timestamptz for all datetime columns
Add GIN index on content for full-text search (optional)

MySQL

Use CHAR(36) or BINARY(16) for UUIDs
Use DATETIME(6) for microsecond precision
Consider utf8mb4 charset for emoji support

SQLite (Development/Small Scale)

Works fine for prototyping
Store UUIDs as TEXT
No native datetime type, store as ISO8601 strings

MongoDB (Document Store)

Embed messages in chat document if message count is bounded
Or use separate collection with chat_id reference
Use TTL index on archived chats for auto-cleanup (optional)

Email Processing Recommendations

Transactional Email Services

Postmark - Best deliverability, simple API
SendGrid - Good free tier, robust
AWS SES - Cheapest at scale
Resend - Modern DX, React email templates

Implementation Pattern

// Always use background jobs for email
Job: SendSupportReplyNotification
  delay: 5 minutes after admin message

  perform(message_id):
    message = find_message(message_id)

    // Guard clauses - don't send if:
    if message.sender_type != 'admin': return
    if message.read_at != null: return        // Already read
    if message.chat.archived?: return         // Chat archived

    send_email(
      to: message.chat.user.email,
      template: 'support_reply',
      data: { message_preview: message.content.truncate(200) }
    )

Email Template Tips

Include message preview (truncated)
Add direct link to open chat (if web app)
Keep subject simple: "New reply from [App] Support"
Include unsubscribe link for compliance

Real-Time Technology Options

Technology	Best For	Serverless?
ActionCable (Rails)	Rails apps	No
Socket.IO	Node.js apps	No
Pusher	Any stack	Yes
Ably	Any stack	Yes
Supabase Realtime	Supabase users	Yes
Firebase RTDB	Firebase users	Yes
Server-Sent Events	Simple one-way	Yes

Fallback Strategy

If WebSocket unavailable, implement polling:

// Poll every 5 seconds when disconnected
if (!websocket.connected) {
  setInterval(() => {
    fetch('/api/support-chat/messages?since=' + lastMessageTime)
      .then(newMessages => appendMessages(newMessages))
  }, 5000)
}

Limitations

Use this skill only when the task clearly matches the scope described above.
Do not treat the output as a substitute for environment-specific validation, testing, or expert review.
Stop and ask for clarification if required inputs, permissions, safety boundaries, or success criteria are missing.

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