diff --git a/packages/web/src/components/modals/ExploreSpacePreviewCard.test.tsx b/packages/web/src/components/modals/ExploreSpacePreviewCard.test.tsx
new file mode 100644
index 00000000..4f05a56d
--- /dev/null
+++ b/packages/web/src/components/modals/ExploreSpacePreviewCard.test.tsx
@@ -0,0 +1,55 @@
+import { describe, it, expect, vi, beforeEach } from 'vitest';
+import { render, screen, waitFor } from '@testing-library/react';
+import userEvent from '@testing-library/user-event';
+
+// Stub AudioManager to avoid AudioWorkletNode reference error in jsdom.
+// Reached transitively via exploreStore → spaceStore → chatStore → useWebSocket → voiceStore.
+vi.mock('../../audio/AudioManager', () => ({
+  AudioManager: {
+    getInstance: vi.fn().mockReturnValue({
+      setOutputDevice: vi.fn(),
+      setVolume: vi.fn(),
+    }),
+  },
+}));
+
+import { ExploreSpacePreviewCard } from './ExploreSpacePreviewCard';
+import { useExploreStore, type TaggedExploreSpace } from '../../stores/exploreStore';
+
+function makeSpace(overrides: Partial<TaggedExploreSpace> = {}): TaggedExploreSpace {
+  return {
+    id: 's1', name: 'Design Guild', icon: null, banner: null, avatarColor: null,
+    description: null, visibility: 'public', memberCount: 5, createdAt: 0,
+    joined: false, _instanceOrigin: '', ...overrides,
+  };
+}
+
+beforeEach(() => {
+  useExploreStore.setState({
+    myRequests: [],
+    publicJoin: vi.fn().mockResolvedValue({ id: 's1', name: 'Design Guild' }),
+    requestJoin: vi.fn().mockResolvedValue({ id: 'r1', spaceId: 's1', status: 'pending' }),
+  });
+});
+
+describe('ExploreSpacePreviewCard', () => {
+  it('renders name, member count and a Join button for public spaces', () => {
+    render(<ExploreSpacePreviewCard space={makeSpace()} onJoinSuccess={vi.fn()} />);
+    expect(screen.getByText('Design Guild')).toBeInTheDocument();
+    expect(screen.getByText(/5 members/)).toBeInTheDocument();
+    expect(screen.getByRole('button', { name: /join/i })).toBeInTheDocument();
+  });
+
+  it('joins a public space and reports success', async () => {
+    const user = userEvent.setup();
+    const onJoinSuccess = vi.fn();
+    render(<ExploreSpacePreviewCard space={makeSpace()} onJoinSuccess={onJoinSuccess} />);
+    await user.click(screen.getByRole('button', { name: /join/i }));
+    await waitFor(() => expect(onJoinSuccess).toHaveBeenCalledWith('s1'));
+  });
+
+  it('shows Request for request-visibility spaces', () => {
+    render(<ExploreSpacePreviewCard space={makeSpace({ visibility: 'request' })} onJoinSuccess={vi.fn()} />);
+    expect(screen.getByRole('button', { name: /request/i })).toBeInTheDocument();
+  });
+});
diff --git a/packages/web/src/components/modals/ExploreSpacePreviewCard.tsx b/packages/web/src/components/modals/ExploreSpacePreviewCard.tsx
new file mode 100644
index 00000000..4422a216
--- /dev/null
+++ b/packages/web/src/components/modals/ExploreSpacePreviewCard.tsx
@@ -0,0 +1,124 @@
+import { useState } from 'react';
+import { useSpaceJoin } from '../../hooks/useSpaceJoin';
+import { getSpaceGradient } from '../../utils/gradients';
+import type { TaggedExploreSpace } from '../../stores/exploreStore';
+
+export function ExploreSpacePreviewCard({
+  space,
+  onJoinSuccess,
+}: {
+  space: TaggedExploreSpace;
+  onJoinSuccess: (spaceId: string) => void;
+}) {
+  const {
+    isPublic,
+    isPending,
+    joining,
+    joinError,
+    showRequestForm,
+    requestMessage,
+    setRequestMessage,
+    openRequestForm,
+    cancelRequestForm,
+    join,
+    sendRequest,
+  } = useSpaceJoin(space);
+
+  const [expanded, setExpanded] = useState(false);
+
+  const fallbackGradient = getSpaceGradient(space.id, space.name, space.avatarColor).gradient;
+  const iconUrl = space.icon
+    ? (space.icon.startsWith('http') || space.icon.startsWith('/') ? space.icon : `/api/uploads/${space.icon}`)
+    : null;
+  const originLabel = space._instanceOrigin
+    ? (() => { try { return new URL(space._instanceOrigin).host; } catch { return space._instanceOrigin; } })()
+    : null;
+
+  const handleJoin = async () => {
+    const full = await join();
+    if (full) onJoinSuccess(full.id);
+  };
+
+  return (
+    <div className="rounded-lg bg-surface-channel border border-border-soft hover:border-border-hard transition-colors px-3 py-2.5">
+      <div className="flex items-center gap-3">
+        {/* Icon */}
+        {iconUrl ? (
+          <img src={iconUrl} alt={space.name} className="w-10 h-10 rounded-lg object-cover flex-shrink-0" />
+        ) : (
+          <div
+            className="w-10 h-10 rounded-lg flex-shrink-0 flex items-center justify-center text-sm font-bold text-white/90"
+            style={{ background: fallbackGradient }}
+          >
+            {space.name.charAt(0).toUpperCase()}
+          </div>
+        )}
+
+        {/* Name + meta */}
+        <div className="min-w-0 flex-1">
+          <div className="text-sm font-semibold text-txt-primary truncate">{space.name}</div>
+          <div className="flex items-center gap-2 text-[12px] text-txt-tertiary">
+            <span>{space.memberCount} {space.memberCount === 1 ? 'member' : 'members'}</span>
+            {originLabel && <span className="truncate text-txt-tertiary/70">· {originLabel}</span>}
+          </div>
+        </div>
+
+        {/* Action */}
+        <div className="flex-shrink-0">
+          {isPublic ? (
+            <button
+              type="button"
+              onClick={handleJoin}
+              disabled={joining}
+              className="px-3 py-1.5 bg-accent-primary hover:bg-accent-primary-hover text-white text-xs font-medium rounded-full transition-colors disabled:opacity-50"
+            >
+              {joining ? 'Joining…' : 'Join'}
+            </button>
+          ) : isPending ? (
+            <span className="px-3 py-1.5 text-xs font-medium text-txt-tertiary">Pending</span>
+          ) : (
+            <button
+              type="button"
+              onClick={() => { openRequestForm(); setExpanded(true); }}
+              className="px-3 py-1.5 bg-accent-amber/20 hover:bg-accent-amber/30 text-accent-amber text-xs font-medium rounded-full transition-colors"
+            >
+              Request
+            </button>
+          )}
+        </div>
+      </div>
+
+      {/* Inline request form */}
+      {showRequestForm && expanded && (
+        <div className="mt-2.5 space-y-2">
+          <textarea
+            value={requestMessage}
+            onChange={(e) => setRequestMessage(e.target.value.slice(0, 200))}
+            placeholder="Why do you want to join? (optional)"
+            rows={2}
+            className="input-standard w-full resize-none text-sm"
+          />
+          <div className="flex gap-2">
+            <button
+              type="button"
+              onClick={sendRequest}
+              disabled={joining}
+              className="flex-1 py-1.5 bg-accent-amber hover:bg-accent-amber/80 text-[#13131a] text-xs font-medium rounded transition-colors disabled:opacity-50"
+            >
+              {joining ? 'Sending…' : 'Send Request'}
+            </button>
+            <button
+              type="button"
+              onClick={() => { cancelRequestForm(); setExpanded(false); }}
+              className="px-3 py-1.5 text-xs text-txt-tertiary hover:text-txt-secondary transition-colors"
+            >
+              Cancel
+            </button>
+          </div>
+        </div>
+      )}
+
+      {joinError && <div className="mt-2 text-[12px] text-txt-danger">{joinError}</div>}
+    </div>
+  );
+}