Selective Read-only sync – A first for CardDAV Contact management

“Why deploy 10,000 contacts to every phone when only 100 matter?”

If you’re managing a mobile team — whether it’s ambulance crews, fire operations, construction teams, or field sales reps — you know the pain of bloated contact lists. Most CardDAV setups force you to sync everything to everyone. It’s messy, insecure, and inefficient.

Contactzilla’s new Selective Read-Only Sync is the first of its kind: a feature that lets you push only the contacts your users need — and lock them as read-only. Furthermore it’s very simple to do.

See how labels and group labels work in Contactzilla, including filtering, bulk updates, and how label structure supports selective CardDAV sync.

Deploy Labels not Lists

Old-school CardDAV systems force you to build separate contact lists or groups for every department, shift, or team. But with Contactzilla, labels become deployment logic.

You can:

• Apply single or multiple labels to segment contacts (e.g. department:publicworks, shift:night, team:dispatch role:driver)
• Create CardDAV connections that sync only the contacts matching those labels
• Set those connections as read-only, so users can’t edit, delete, or break the list

This approach transforms your address book into a modular system, delivering:

• Enhanced productivity by providing users with only the contacts they need
• Improved control over contact distribution and access
• Faster synchronization due to reduced data loads
• A simplified user experience that minimizes confusion and errors

Share read-only contact lists across 100’s of devices

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Real Teams, Real Problems — How we solve it

We’ve spoken with several emergency services teams — now Contactzilla customers — who all pointed to the same issue. Not everyone needs the same contacts.

From battalion chiefs to medics, from rig crews to admin staff — the contact needs vary massively. One team explained how their vehicles needed hospital and dispatch numbers, while office staff needed access to internal leadership and station directories. With Contactzilla’s label-based selective sync, each group now gets only what they need — no more, no less.

In another case two neighboring fire departments working together on joint operations needed to securely share a small subset of contacts across agencies — without exposing their full directory. With Selective Read-Only Sync, they simply applied a label and deployed it to the right teams.

Of course, that wasn’t the only headache. Some departments were still loading contact files manually to each phone with vCards. Updates were missed, contacts got stale, and in one case, personal numbers made their way into the shared list.

Selective Read-Only Sync fixes all of it — segmenting contacts, locking them as read-only, and syncing them to only the right devices.

Built for Shared Devices

Selective Read-Only Sync was built with shared iPhones and shift-based crews in mind. Think medical teams, parks departments, construction crews, and utilities — where phones are handed down from shift to shift and no one logs in.

In these environments, syncing contacts at the device level is essential. There’s no user account to tie the sync to — the contact list needs to follow the phone, not the person.

That’s exactly where Selective Read-Only Sync shines. It pushes just the right contacts to each device — no clutter, no risk — and locks them in place. Users can’t accidentally alter or delete anything. And because the sync is tied to the device connection, not a login, it fits seamlessly into shift-based workflows.

Traditional solutions like Google or third-party CardDAV servers often fall short. End users can accidentally edit or delete shared contacts, and the result is messy, unreliable data that’s impossible to control at scale.

The goal for these organizations is simple:

• Push the right contact list to each device
• Make it read-only, so users can’t tamper with it
• Keep it up to date, centrally managed
• Deploy at scale — 10 phones or 1,000 — without logging in to each one

And crucially: they don’t want to touch each phone. Admins need a system that lets them make updates once, in a central portal, and have those changes cascade silently out to the field. Contactzilla makes that seamless. Whether it’s medical crews rotating shifts, parks departments sharing iPhones, or utility teams syncing on rugged Android devices, Selective Read-Only Sync gives you locked-down lists that update automatically — without any manual fuss or vCard juggling.

Security – CardDAV, reimagined for modern IT

“Management wants me to find a way for all contacts to be constantly accurate and up to date across all phones, so people don’t have to add new starters, or delete leavers.” — Reddit

We hear this kind of thing all the time — especially from teams with sensitive contact data or high staff turnover.

With Selective Read-Only Sync, you can:

• Instantly revoke access by removing the connection
• Keep every contact list centrally managed
• Sleep easy knowing only the right people have the right data

all from a clean visual interface. For organizations with compliance, confidentiality, or operational security needs, it’s a simple but powerful step forward.

“It’s a small but very cool feature — and people love it.” — Tom, Contactzilla Founder

Tip 💡: For non-MDM setups — like BYOD sales teams — we’ve also just launched Wipe-On-Next-Connect. If someone leaves your org, the next time their phone connects, the contact list is wiped. No chasing. No awkward conversations. Just clean exits, built in.Watch the Wipe-On-Next-Connect video

Frequently Asked Questions

Can I import contacts into Contactzilla from Sharepoint?

Yes, you can. We’ve recently released a simple walkthrough showing how to sync SharePoint contacts into Contactzilla using our import process. Watch the SharePoint contact import video to see exactly how it works.

What is Read-only selective sync for contact management?

Selective sync lets you deploy only the contacts a user needs — not the entire address book. It’s especially useful for shared or shift-based devices, where different teams need different contact lists. Contactzilla takes it further by making those contacts read-only, so they can’t be edited or deleted on the device.

Can I send different contact lists to different teams?

Yes. With Contactzilla, you can use labels to create filtered contact groups — such as by department, role, or location — and deploy only the relevant contacts to each team’s devices. As an alternative you can create separate address books for each team or department and sync those.