---
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: 2026-10-02
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
---

# 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. Keys are strings (`tostring(UserId)`); values are integers used for sorting.
- `GetSortedAsync(ascending, pageSize, minValue, maxValue)` → sorted pages
- `BatchGetAsync(keys)`: multi-key read, ordered stores only; missing keys are omitted
- Budget: poll `GetRequestBudgetForRequestType(OrderedWrite)` before bursts (per server: 30 + numPlayers x 5 writes/min)
- For leaderboards only, never for player saves
- Keep the user ID a static substring in keys (`player_<UserId>`) so RTBF templates match; hashed keys make erasure manual

### MessagingService (Cross-Server)
- `SubscribeAsync` / `PublishAsync`; no delivery or ordering guarantee, so design for idempotency.
- Request/response: `{reqId}` correlation, ack on the topic, timeout. No ack ≠ not executed — replay the same reqId, don't double-grant.

### 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.

### Cross-Server Patterns
- Register servers with expiring heartbeats; use MessagingService for notifications.

### User Identity
- New code identifies users with `player.User` (`User.Id`, `DomainType`, `DomainId`); `UserId` stays valid. Domain IDs are per-experience, so keep cross-server keys on `UserId` and never mix the two.

### Pitfalls
- MessagingService: fire-and-forget, unordered, cross-server latency; not for time-critical work
- GlobalDataStore: same rate limits as player DataStores
- Never store Instances; serialize to primitives first; `SetAsync` overwrites — use `UpdateAsync` for shared counters

> Store selection and workflows: [references/full.md](references/full.md)