curl -X POST 'https://api.example.com/memberships' \
  -H 'Authorization: Bearer YOUR_TOKEN' \
  -H 'Content-Type: application/json' \
  -d '{
    "subjectId": "sub_123",
    "scopeId": "scope_456"
  }'

const axios = require('axios');

const { data } = await axios.post('https://api.example.com/memberships', {
  subjectId: 'sub_123',
  scopeId: 'scope_456',
}, {
  headers: { 'Authorization': 'Bearer YOUR_TOKEN' },
});

{
  "id": "mem_789",
  "subjectId": "sub_123",
  "scopeId": "scope_456"
}