You can sync your contacts both ways between Follow Up Boss and Google using Real Synch. Here are the setup instructions for each direction.
Setup Instructions
1. From your Real Synch dashboard, click+ Add Integration
2. Select Google Contacts as your Source and Follow Up Boss as your Target
3. Click Instructions on the Google Contacts icon and follow along
Click Connect, and if you would like to add multiple accounts, ensure the option is enabled:
Note: This option requires Admin access in Google Contacts
5. Click Sign in with Google > Allow > Close
6. Click the Instructions link for Follow Up Boss and follow the on screen directions to retrieve your API Key
7. Then click Connect > Add API Key > Verify > Close
8. Both Source and Target connections should now display as Verified > Click Next and Activate
9. Your integration is now active! You can access and update your Integration's Source and Target Options by clicking the wrench icon next to the Source and Target on the Real Synch dashboard.
Follow Up Boss to Google Contacts Integration
Setup Instructions:
1. From your Real Synch dashboard, click + Add Integration
2. Select Follow Up Boss as your Source and Google Contacts as your Target
3. Click Instructions on the Follow Up Boss icon and follow along
4. Then click Connect > Add API Key > Verify > Close
5. Next, click the instructions on the Google Contacts icon and follow along
6. Click Connect, and if you would like to add multiple accounts, ensure the option is enabled
Note: This option requires Admin access in Google Contacts
Click Sign in with Google > Allow > Close
8. Both Source and Target connections should now display as Verified > Next > Activate
9. Your integration is now active! You can access and update your Integration's Source Options by clicking the wrench icon next to the Source on the Real Synch dashboard.
Resource: Real Synch Help Articles