curl -X POST "https://server.smartlead.ai/api/v1/crm/leads/tags?api_key=YOUR_KEY" \
  -H "Content-Type: application/json" \
  -d '{"leadId": 123, "tagIds": [1, 2, 3]}'

{
  "ok": true,
  "message": "Tags added to lead successfully"
}

{
  "message": "Invalid API Key"
}