version: "1.0.1" name: roblox-server-data description: "Use when building or fixing Roblox cross-server data: OrderedDataStore leaderboards, MessagingService, MemoryStore, world state, seasons." when_to_use: "Also for global leaderboards, cross-server announcements or events, matchmaking queues, shared counters, and reviewing non-player persistence." last_reviewed: 2026-10-14 sources:

• https://create.roblox.com/docs/reference/engine/classes/MemoryStoreSortedMap
• https://create.roblox.com/docs/reference/engine/classes/OrderedDataStore
• https://create.roblox.com/docs/reference/engine/classes/MessagingService
• https://create.roblox.com/docs/reference/engine/classes/MemoryStoreService
• https://create.roblox.com/docs/reference/engine/classes/DataStoreService
• https://create.roblox.com/docs/cloud-services/data-stores/right-to-be-forgotten
• https://create.roblox.com/docs/cloud-services/data-stores/error-codes-and-limits
• original

Roblox Server & Shared Data

When to Load

Load for leaderboards, messaging, MemoryStore coordination, world state, seasons, or guilds. Player persistence: roblox-data; Open Cloud: roblox-cloud.

Quick Reference

OrderedDataStore (Leaderboards)

• Sortable DataStore: string keys (tostring(UserId)), integer sort values; GetSortedAsync → pages; BatchGetAsync multi-key read (missing keys omitted).
• Budget bursts via GetRequestBudgetForRequestType(OrderedWrite) (per server: 30 + numPlayers×5 writes/min).
• Leaderboards only, never player saves. Keep player_<UserId> a static key substring so RTBF templates match.

MessagingService (Cross-Server)

• SubscribeAsync / PublishAsync; no delivery or ordering guarantee — design for idempotency.
• Request/response: {reqId} correlation + ack + timeout; no ack ≠ not executed — replay same reqId, don't double-grant.
• Budget broadcast receives, not just sends; limits and polling trade-offs: full.md. <!-- temporal: 2026-10 -->

GlobalDataStore (Shared State)

• Persistent non-player state (guilds, seasons, counters). Use UpdateAsync; never for player session data.

MemoryStoreService (Temporary Coordination)

• Queues and sorted maps for expiring matchmaking, leases, coordination.
• Remove a read batch only after successful, idempotent processing.
• Sorted-map paging: last item's {key, sortKey} = next exclusive bound. Quotas are game-level (one shared pool): request units 1000+120×CCU/min, memory 64 KB+1.2 KB/user, value ≤32 KB, TTL 45 days; batch calls bill per item. <!-- temporal: 2026-10 -->

Cross-Server Patterns

• Register servers with expiring heartbeats; notify via MessagingService.

User Identity

• Identify users with player.User (User.Id, DomainType, DomainId); UserId stays valid. Domain IDs are per-experience: key cross-server data on UserId.

Pitfalls

• MessagingService: fire-and-forget, unordered; not for time-critical work
• GlobalDataStore: same rate limits as player DataStores
• Never store Instances; SetAsync overwrites — use UpdateAsync for shared counters

Store selection and workflows: references/full.md