I personally use a paid E-Mail service (mailbox.org) and a self hosted nextcloud.
The APP myphoneexplorer can be used to sync offline.
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UPDATE: Thanks for the comments so far. To clarify my situation:
My main use cases are: Gmail (personal): For personal contacts. Gmail (work): For professional contacts related to my role. Outlook (work): For internal and external business communication. LinkedIn: Managing professional connections. Messaging apps (WhatsApp, Messenger, etc.): Keeping in touch with a wide range of contacts.
I’ve tried syncing across these platforms using Google Contacts, vCard exports, and a few automation tools, but the results have been inconsistent. Either the syncing doesn't work as expected, or there’s a lot of manual cleanup involved—especially when contacts change roles or details across different apps.
I’m wondering if anyone has found a more seamless way to manage contacts across all these different contexts? I’d love to hear any recommendations for more advanced tools, automations, or strategies that have worked for you.
I personally use a paid E-Mail service (mailbox.org) and a self hosted nextcloud.
The APP myphoneexplorer can be used to sync offline.
I guess it won’t tell big tech who your friends are. At least until you talk with them regularly through online channels.
- phone - this is kind of ok, because phone spam is less common
- email - to prevent spam
- birthday - this one is quite critical, because here in germany it is a common way to verify authentication on phone calls by insurance companies
- job-details, contact relationships, etc.
I doubt that these are all in the public registry.