ant-design/components/float-button/demo/badge.tsx

import { QuestionCircleOutlined } from '@ant-design/icons';
import React from 'react';
import { FloatButton } from 'antd';

const App: React.FC = () => (
  <>
    <FloatButton shape="circle" badge={{ dot: true }} style={{ right: 24 + 70 + 70 }} />
    <FloatButton.Group shape="circle" style={{ right: 24 + 70 }}>
      <FloatButton tooltip={<div>custom badge color</div>} badge={{ count: 5, color: 'blue' }} />
      <FloatButton badge={{ count: 5 }} />
    </FloatButton.Group>
    <FloatButton.Group shape="circle">
      <FloatButton badge={{ count: 12 }} icon={<QuestionCircleOutlined />} />
      <FloatButton badge={{ count: 123, overflowCount: 999 }} />
      <FloatButton.BackTop visibilityHeight={0} />
    </FloatButton.Group>
  </>
);

export default App;