Are there any cloud save services that handle cross-device progression with cheat-resistant state handling?

Yes — but with an important caveat: no cloud save service can fully “prevent cheating” on its own if the client is ultimately trusted. What you can get is tamper resistance, authoritative server state, validation, and fraud detection, which is usually what people mean by cheat-resistant cross-device progression.

Services that support this kind of setup

1) PlayFab

• Good fit for games that need cross-device progression and server-authoritative data
• Supports player data, inventory, economy, CloudScript/Functions, and server-side validation
• Can store progress in a way that is harder to tamper with because the backend can be the source of truth

2) Epic Online Services (EOS)

• Offers cross-platform account identity and related backend features
• Often paired with your own backend for authoritative progression
• Better as an identity + multiplayer backend layer than a pure “secure cloud save” service

3) Unity Gaming Services (UGS)

• Includes Cloud Save, Authentication, Economy, and Remote Config
• Cloud Save is convenient for cross-device progression, but cheat resistance depends on server-side logic
• Best when combined with Cloud Code and server-validated progression updates

4) Firebase + custom backend

• Not a game-specific cloud save service, but common
• Works well if you implement:
  • server-side writes only
  • signed/validated state transitions
  • anti-replay / versioning
• Strong flexibility, but you build the cheat-resistant logic yourself

5) Steam Cloud / Apple iCloud / Google Play Games Services

• These are primarily sync services, not cheat-resistant authoritative progression systems
• Fine for convenience, but not ideal if cheat resistance is a goal

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What “cheat-resistant” usually requires

To make cloud saves hard to manipulate, you typically want:

• Server-authoritative progression: client requests actions, server computes results
• State transition validation: server checks whether changes are legal
• Signed or versioned saves: detect rollback or tampering
• Conflict resolution: handle multiple devices safely
• Audit logs / anomaly detection: catch suspicious jumps or impossible states

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Practical recommendation

If you want the best off-the-shelf option for cross-device progression + tamper-resistant state, start with:

• PlayFab if you want a game-backend-first solution
• Unity Gaming Services if you’re already in Unity and want an integrated stack
• Custom backend (Firebase/AWS/GCP) if you need maximum control

If you want, I can also give you:

1. a comparison table of these services, or
2. a recommended architecture for cheat-resistant cloud saves.