diff --git a/package-lock.json b/package-lock.json
index ce4ae0b..1031623 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -50,6 +50,7 @@
 				"marked": "^15.0.4",
 				"one-webcrypto": "^1.0.3",
 				"openai": "^4.79.3",
+				"qrcode.react": "^4.2.0",
 				"rbush": "^4.0.1",
 				"react": "^18.2.0",
 				"react-cmdk": "^1.3.9",
@@ -80,6 +81,7 @@
 			},
 			"engines": {
 				"node": ">=20.0.0"
+<<<<<<< HEAD
 			}
 		},
 		"multmux/packages/cli": {
@@ -197,6 +199,8 @@
 				"utf-8-validate": {
 					"optional": true
 				}
+=======
+>>>>>>> db7bbbf (feat: add invite/share feature with QR code, URL, NFC, and audio connect)
 			}
 		},
 		"node_modules/@ai-sdk/provider": {
@@ -14887,6 +14891,14 @@
 				"url": "https://github.com/sponsors/ljharb"
 			}
 		},
+		"node_modules/qrcode.react": {
+			"version": "4.2.0",
+			"resolved": "https://registry.npmjs.org/qrcode.react/-/qrcode.react-4.2.0.tgz",
+			"integrity": "sha512-QpgqWi8rD9DsS9EP3z7BT+5lY5SFhsqGjpgW5DY/i3mK4M9DTBNz3ErMi8BWYEfI3L0d8GIbGmcdFAS1uIRGjA==",
+			"peerDependencies": {
+				"react": "^16.8.0 || ^17.0.0 || ^18.0.0 || ^19.0.0"
+			}
+		},
 		"node_modules/querystringify": {
 			"version": "2.2.0",
 			"resolved": "https://registry.npmjs.org/querystringify/-/querystringify-2.2.0.tgz",
diff --git a/package.json b/package.json
index a95efaa..e0a8ee3 100644
--- a/package.json
+++ b/package.json
@@ -67,6 +67,7 @@
 		"marked": "^15.0.4",
 		"one-webcrypto": "^1.0.3",
 		"openai": "^4.79.3",
+		"qrcode.react": "^4.2.0",
 		"rbush": "^4.0.1",
 		"react": "^18.2.0",
 		"react-cmdk": "^1.3.9",
diff --git a/src/components/ShareBoardButton.tsx b/src/components/ShareBoardButton.tsx
new file mode 100644
index 0000000..b647b4e
--- /dev/null
+++ b/src/components/ShareBoardButton.tsx
@@ -0,0 +1,70 @@
+import React from 'react';
+import { useParams } from 'react-router-dom';
+import { useDialogs } from 'tldraw';
+import { InviteDialog } from '../ui/InviteDialog';
+
+interface ShareBoardButtonProps {
+  className?: string;
+}
+
+const ShareBoardButton: React.FC<ShareBoardButtonProps> = ({ className = '' }) => {
+  const { slug } = useParams<{ slug: string }>();
+  const { addDialog, removeDialog } = useDialogs();
+
+  const handleShare = () => {
+    const boardSlug = slug || 'mycofi33';
+    const boardUrl = `${window.location.origin}/board/${boardSlug}`;
+
+    addDialog({
+      id: "invite-dialog",
+      component: ({ onClose }: { onClose: () => void }) => (
+        <InviteDialog
+          onClose={() => {
+            onClose();
+            removeDialog("invite-dialog");
+          }}
+          boardUrl={boardUrl}
+          boardSlug={boardSlug}
+        />
+      ),
+    });
+  };
+
+  return (
+    <button
+      onClick={handleShare}
+      className={`share-board-button ${className}`}
+      title="Invite others to this board"
+      style={{
+        padding: "4px 8px",
+        borderRadius: "4px",
+        background: "#3b82f6",
+        color: "white",
+        border: "none",
+        cursor: "pointer",
+        fontWeight: 500,
+        transition: "background 0.2s ease",
+        boxShadow: "0 2px 4px rgba(0,0,0,0.1)",
+        whiteSpace: "nowrap",
+        userSelect: "none",
+        display: "flex",
+        alignItems: "center",
+        gap: "4px",
+        height: "22px",
+        minHeight: "22px",
+        boxSizing: "border-box",
+        fontSize: "0.75rem",
+      }}
+      onMouseEnter={(e) => {
+        e.currentTarget.style.background = "#2563eb";
+      }}
+      onMouseLeave={(e) => {
+        e.currentTarget.style.background = "#3b82f6";
+      }}
+    >
+      <span style={{ fontSize: "12px" }}>Share</span>
+    </button>
+  );
+};
+
+export default ShareBoardButton;
diff --git a/src/ui/CustomToolbar.tsx b/src/ui/CustomToolbar.tsx
index 944fb9c..f1cdc6e 100644
--- a/src/ui/CustomToolbar.tsx
+++ b/src/ui/CustomToolbar.tsx
@@ -8,6 +8,7 @@ import { SettingsDialog } from "./SettingsDialog"
 import { useAuth } from "../context/AuthContext"
 import LoginButton from "../components/auth/LoginButton"
 import StarBoardButton from "../components/StarBoardButton"
+import ShareBoardButton from "../components/ShareBoardButton"
 import { ObsidianVaultBrowser } from "../components/ObsidianVaultBrowser"
 import { HolonBrowser } from "../components/HolonBrowser"
 import { ObsNoteShape } from "../shapes/ObsNoteShapeUtil"
@@ -652,8 +653,8 @@ export function CustomToolbar() {
         }}
       >
         <LoginButton className="toolbar-btn" />
+        <ShareBoardButton className="toolbar-btn" />
         <StarBoardButton className="toolbar-btn" />
-
         {session.authed && (
           <div style={{ position: "relative" }}>
             <button
diff --git a/src/ui/InviteDialog.tsx b/src/ui/InviteDialog.tsx
new file mode 100644
index 0000000..d589cd0
--- /dev/null
+++ b/src/ui/InviteDialog.tsx
@@ -0,0 +1,352 @@
+import {
+  TLUiDialogProps,
+  TldrawUiButton,
+  TldrawUiButtonLabel,
+  TldrawUiDialogBody,
+  TldrawUiDialogCloseButton,
+  TldrawUiDialogFooter,
+  TldrawUiDialogHeader,
+  TldrawUiDialogTitle,
+} from "tldraw"
+import React, { useState, useEffect } from "react"
+import { QRCodeSVG } from "qrcode.react"
+
+interface InviteDialogProps extends TLUiDialogProps {
+  boardUrl: string
+  boardSlug: string
+}
+
+type TabType = 'qr' | 'url' | 'nfc' | 'audio'
+
+export function InviteDialog({ onClose, boardUrl, boardSlug }: InviteDialogProps) {
+  const [activeTab, setActiveTab] = useState<TabType>('qr')
+  const [copied, setCopied] = useState(false)
+  const [nfcStatus, setNfcStatus] = useState<'idle' | 'writing' | 'success' | 'error' | 'unsupported'>('idle')
+  const [nfcMessage, setNfcMessage] = useState('')
+
+  // Check NFC support on mount
+  useEffect(() => {
+    if (!('NDEFReader' in window)) {
+      setNfcStatus('unsupported')
+    }
+  }, [])
+
+  const handleCopyUrl = async () => {
+    try {
+      await navigator.clipboard.writeText(boardUrl)
+      setCopied(true)
+      setTimeout(() => setCopied(false), 2000)
+    } catch (err) {
+      console.error('Failed to copy URL:', err)
+    }
+  }
+
+  const handleNfcWrite = async () => {
+    if (!('NDEFReader' in window)) {
+      setNfcStatus('unsupported')
+      setNfcMessage('NFC is not supported on this device')
+      return
+    }
+
+    try {
+      setNfcStatus('writing')
+      setNfcMessage('Hold your NFC tag near the device...')
+
+      const ndef = new (window as any).NDEFReader()
+      await ndef.write({
+        records: [
+          { recordType: "url", data: boardUrl }
+        ]
+      })
+
+      setNfcStatus('success')
+      setNfcMessage('Board URL written to NFC tag!')
+      setTimeout(() => {
+        setNfcStatus('idle')
+        setNfcMessage('')
+      }, 3000)
+    } catch (err: any) {
+      console.error('NFC write error:', err)
+      setNfcStatus('error')
+      if (err.name === 'NotAllowedError') {
+        setNfcMessage('NFC permission denied. Please allow NFC access.')
+      } else if (err.name === 'NotSupportedError') {
+        setNfcMessage('NFC is not supported on this device')
+      } else {
+        setNfcMessage(`Failed to write NFC tag: ${err.message || 'Unknown error'}`)
+      }
+    }
+  }
+
+  const tabStyle = (tab: TabType) => ({
+    flex: 1,
+    padding: '10px 16px',
+    border: 'none',
+    background: activeTab === tab ? '#3b82f6' : '#f3f4f6',
+    color: activeTab === tab ? 'white' : '#374151',
+    cursor: 'pointer',
+    fontWeight: activeTab === tab ? 600 : 400,
+    fontSize: '13px',
+    transition: 'all 0.2s ease',
+    borderRadius: tab === 'qr' ? '6px 0 0 6px' : tab === 'audio' ? '0 6px 6px 0' : '0',
+  })
+
+  return (
+    <>
+      <TldrawUiDialogHeader>
+        <TldrawUiDialogTitle>Invite to Board</TldrawUiDialogTitle>
+        <TldrawUiDialogCloseButton />
+      </TldrawUiDialogHeader>
+      <TldrawUiDialogBody style={{ maxWidth: 420, minHeight: 380 }}>
+        <div style={{ display: "flex", flexDirection: "column", gap: 16 }}>
+          {/* Board name display */}
+          <div style={{
+            textAlign: 'center',
+            padding: '8px 12px',
+            backgroundColor: '#f8fafc',
+            borderRadius: '6px',
+            border: '1px solid #e2e8f0'
+          }}>
+            <span style={{ fontSize: '12px', color: '#64748b' }}>Board: </span>
+            <span style={{ fontSize: '14px', fontWeight: 600, color: '#1e293b' }}>{boardSlug}</span>
+          </div>
+
+          {/* Tab navigation */}
+          <div style={{ display: 'flex', borderRadius: '6px', overflow: 'hidden' }}>
+            <button style={tabStyle('qr')} onClick={() => setActiveTab('qr')}>
+              QR Code
+            </button>
+            <button style={tabStyle('url')} onClick={() => setActiveTab('url')}>
+              URL
+            </button>
+            <button style={tabStyle('nfc')} onClick={() => setActiveTab('nfc')}>
+              NFC
+            </button>
+            <button style={tabStyle('audio')} onClick={() => setActiveTab('audio')}>
+              Audio
+            </button>
+          </div>
+
+          {/* Tab content */}
+          <div style={{
+            minHeight: 220,
+            display: 'flex',
+            flexDirection: 'column',
+            alignItems: 'center',
+            justifyContent: 'center',
+            padding: '16px',
+            backgroundColor: '#fafafa',
+            borderRadius: '8px',
+            border: '1px solid #e5e7eb'
+          }}>
+            {activeTab === 'qr' && (
+              <div style={{ textAlign: 'center' }}>
+                <div style={{
+                  padding: '16px',
+                  backgroundColor: 'white',
+                  borderRadius: '12px',
+                  boxShadow: '0 2px 8px rgba(0,0,0,0.1)',
+                  display: 'inline-block'
+                }}>
+                  <QRCodeSVG
+                    value={boardUrl}
+                    size={180}
+                    level="M"
+                    includeMargin={false}
+                  />
+                </div>
+                <p style={{
+                  marginTop: '16px',
+                  fontSize: '13px',
+                  color: '#6b7280',
+                  lineHeight: 1.5
+                }}>
+                  Scan this QR code with a mobile device to join the board
+                </p>
+              </div>
+            )}
+
+            {activeTab === 'url' && (
+              <div style={{ width: '100%', textAlign: 'center' }}>
+                <div style={{
+                  padding: '12px',
+                  backgroundColor: 'white',
+                  borderRadius: '8px',
+                  border: '1px solid #d1d5db',
+                  marginBottom: '16px',
+                  wordBreak: 'break-all',
+                  fontSize: '13px',
+                  fontFamily: 'monospace',
+                  color: '#374151'
+                }}>
+                  {boardUrl}
+                </div>
+                <button
+                  onClick={handleCopyUrl}
+                  style={{
+                    padding: '10px 24px',
+                    backgroundColor: copied ? '#10b981' : '#3b82f6',
+                    color: 'white',
+                    border: 'none',
+                    borderRadius: '6px',
+                    cursor: 'pointer',
+                    fontSize: '14px',
+                    fontWeight: 500,
+                    transition: 'all 0.2s ease',
+                    display: 'flex',
+                    alignItems: 'center',
+                    gap: '8px',
+                    margin: '0 auto'
+                  }}
+                >
+                  {copied ? (
+                    <>
+                      <span>Copied!</span>
+                    </>
+                  ) : (
+                    <>
+                      <span>Copy URL</span>
+                    </>
+                  )}
+                </button>
+                <p style={{
+                  marginTop: '16px',
+                  fontSize: '13px',
+                  color: '#6b7280'
+                }}>
+                  Share this link with anyone to invite them to your board
+                </p>
+              </div>
+            )}
+
+            {activeTab === 'nfc' && (
+              <div style={{ width: '100%', textAlign: 'center' }}>
+                {nfcStatus === 'unsupported' ? (
+                  <>
+                    <div style={{
+                      fontSize: '48px',
+                      marginBottom: '16px',
+                      opacity: 0.5
+                    }}>
+                      NFC
+                    </div>
+                    <p style={{
+                      fontSize: '14px',
+                      color: '#6b7280',
+                      marginBottom: '8px'
+                    }}>
+                      NFC is not supported on this device
+                    </p>
+                    <p style={{
+                      fontSize: '12px',
+                      color: '#9ca3af'
+                    }}>
+                      Try using a mobile device with NFC capability
+                    </p>
+                  </>
+                ) : (
+                  <>
+                    <div style={{
+                      fontSize: '48px',
+                      marginBottom: '16px',
+                      animation: nfcStatus === 'writing' ? 'pulse 1.5s infinite' : 'none'
+                    }}>
+                      {nfcStatus === 'success' ? '(done)' : nfcStatus === 'error' ? '(!)' : 'NFC'}
+                    </div>
+                    <button
+                      onClick={handleNfcWrite}
+                      disabled={nfcStatus === 'writing'}
+                      style={{
+                        padding: '10px 24px',
+                        backgroundColor: nfcStatus === 'success' ? '#10b981' :
+                                        nfcStatus === 'error' ? '#ef4444' :
+                                        nfcStatus === 'writing' ? '#9ca3af' : '#3b82f6',
+                        color: 'white',
+                        border: 'none',
+                        borderRadius: '6px',
+                        cursor: nfcStatus === 'writing' ? 'not-allowed' : 'pointer',
+                        fontSize: '14px',
+                        fontWeight: 500,
+                        marginBottom: '12px'
+                      }}
+                    >
+                      {nfcStatus === 'writing' ? 'Writing...' :
+                       nfcStatus === 'success' ? 'Written!' :
+                       'Write to NFC Tag'}
+                    </button>
+                    {nfcMessage && (
+                      <p style={{
+                        fontSize: '13px',
+                        color: nfcStatus === 'error' ? '#ef4444' :
+                               nfcStatus === 'success' ? '#10b981' : '#6b7280'
+                      }}>
+                        {nfcMessage}
+                      </p>
+                    )}
+                    {!nfcMessage && (
+                      <p style={{
+                        fontSize: '13px',
+                        color: '#6b7280'
+                      }}>
+                        Write the board URL to an NFC tag for instant access
+                      </p>
+                    )}
+                  </>
+                )}
+              </div>
+            )}
+
+            {activeTab === 'audio' && (
+              <div style={{ width: '100%', textAlign: 'center' }}>
+                <div style={{
+                  fontSize: '48px',
+                  marginBottom: '16px',
+                  opacity: 0.6
+                }}>
+                  ((( )))
+                </div>
+                <p style={{
+                  fontSize: '14px',
+                  color: '#374151',
+                  fontWeight: 500,
+                  marginBottom: '8px'
+                }}>
+                  Audio Connect
+                </p>
+                <p style={{
+                  fontSize: '13px',
+                  color: '#6b7280',
+                  marginBottom: '16px'
+                }}>
+                  Share the board link via ultrasonic audio
+                </p>
+                <div style={{
+                  padding: '12px 16px',
+                  backgroundColor: '#fef3c7',
+                  borderRadius: '8px',
+                  border: '1px solid #fcd34d',
+                  fontSize: '12px',
+                  color: '#92400e'
+                }}>
+                  Coming soon! Audio-based sharing will allow nearby devices to join by listening for an ultrasonic signal.
+                </div>
+              </div>
+            )}
+          </div>
+        </div>
+      </TldrawUiDialogBody>
+      <TldrawUiDialogFooter>
+        <TldrawUiButton type="primary" onClick={onClose}>
+          <TldrawUiButtonLabel>Done</TldrawUiButtonLabel>
+        </TldrawUiButton>
+      </TldrawUiDialogFooter>
+
+      <style>{`
+        @keyframes pulse {
+          0%, 100% { opacity: 1; }
+          50% { opacity: 0.5; }
+        }
+      `}</style>
+    </>
+  )
+}