Alternativas ao Tars para Facebook Messenger com licença de código aberto

• Facebook Messenger
  Todas as plataformas Windows Android iPhone iPad Android Tablet Web Self-Hosted Software as a Service (SaaS) Facebook Slack Facebook Messenger Gmail Twitter MailChimp Trello Salesforce.com HubSpot Google Drive - Sheets Intercom Autopilot Wit.ai Watson Conversation Api.ai
• Licença Open Source
  Qualquer licença Licença gratuita Licença Open Source Licença comercial