Thanks for confirming, Paul.

I considered Messaging, but I saw 'bulk messaging' to all users was still in the works. Even if we could msg all players, for something like a "maintenance apology gift", pushing a single Global Entity versus iterating through every profile ID to send a msg seemed like the better option--BUT, I'm still learning, so I could be wrong.

I didn't see an in-game mailbox referenced in the docs, but it seems this is achievable by using Global Entities to push messages from the system via API Hooks (like a "welcome gift" that is sent after a first-time authentication, or a tournament prize after a tournament concludes), and a User Entity to track if a message was read or the Item Bundle was claimed.

It seems Custom Entities are an even better fit for this, since then, we can search for players that are, say > level 20, and push a special mail message to them, right?

Is this the most best way to approach an in-game mailbox in brainCloud, and what hurdles might I run into by handling it this way? Would this let me safely bypass the limitations around awarding Items for milestones/quests?

Here is my code for a "GetMailbox" cloud script, for reference:

"use strict";

function main() {
    var entityProxy = bridge.getEntityServiceProxy();       // for user entities (tracker)
    var globalProxy = bridge.getGlobalEntityServiceProxy(); // for global entities (server mail)
    
    // fetch global mail manifest using global proxy
    var globalMails =[];
    var globalRes = globalProxy.getList({ "entityType": "globalMail" }, {}, 50);
    if (globalRes.data.entityList) {
        for (var i = 0; i < globalRes.data.entityList.length; i++) {
            globalMails.push(globalRes.data.entityList[i].data);
        }
    }

    // fetch user's personal mailbox tracker
    var userRes = entityProxy.getList({ "entityType": "mailbox" }, {}, 1);
    var mailboxEntity;
    
    if (userRes.data.entityList && userRes.data.entityList.length > 0) {
        mailboxEntity = userRes.data.entityList[0].data;
        
        // safety: ensure arrays exist if entity was somehow corrupted
        if (!mailboxEntity.claimedGlobalIds) mailboxEntity.claimedGlobalIds =[];
        if (!mailboxEntity.personalMail) mailboxEntity.personalMail =[];
    } else {
        // create if it doesn't exist
        mailboxEntity = { claimedGlobalIds: [], personalMail:[] };
        entityProxy.createEntity("mailbox", mailboxEntity, null);
    }

    // merge/format for client
    var mergedInbox =[];

    // global mail
    for (var g = 0; g < globalMails.length; g++) {
        var gMail = globalMails[g];
        // if msg ID is in claimed list, mark as read/claimed
        gMail.isClaimed = (mailboxEntity.claimedGlobalIds.indexOf(gMail.messageId) !== -1);
        gMail.isRead = gMail.isClaimed; 
        gMail.type = "GLOBAL";
        mergedInbox.push(gMail);
    }

    // personal mail
    for (var p = 0; p < mailboxEntity.personalMail.length; p++) {
        var pMail = mailboxEntity.personalMail[p];
        pMail.type = "PERSONAL";
        mergedInbox.push(pMail);
    }

    return { messages: mergedInbox };
}

main();