CRM tool for a Tech Startup: Any suggestions?

Hello,

I am looking for a CRM tool for a tech startup that can:

• Track Opportunity stages
  • Opportunity Stages preferably need to be customisable
• Assign contacts within accounts to different people than the account holder
  • Assign commercial contacts to sales, tech contacts to support, etc
• Forecast / Track revenue
  • API and SDK based products
• Track API consumption of users
• Log interaction with an account
  • Both commercially and technically.
  • These need to be separated from each other
• Preferably allow for Slack integration for both Internal and External communication

What are your recommendations? I'm looking around and am not sure which one is most compatible.