Cloud Sync & REST Webhooks

Synchronize player progression across mobile and PC backends with HMAC-SHA256 signatures, conflict resolution, and offline queuing.

Table of Contents

1. ☁️ Supported Backend Architectures
2. 🔒 HMAC-SHA256 Tamper Verification
3. 📶 CloudOfflineQueue Resilience
4. 🔀 Conflict Resolution Strategies (CloudMergeStrategy)

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☁️ Supported Backend Architectures

ACHIEVE PRO connects seamlessly to any backend:

• PlayFab (Title Data / Player Statistics)
• Firebase / Firestore
• Supabase / PostgreSQL
• Custom Node.js / Python / Go REST Webhooks

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🔒 HMAC-SHA256 Tamper Verification

All cloud payloads dispatched by CloudSyncAdapter include an X-Achievement-Signature header calculated via HMAC-SHA256 using your private server secret. This prevents packet interception and unauthorized score spoofing.

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📶 CloudOfflineQueue Resilience

When players play offline (airplane mode, subway, network loss):

• Unlocks and progress steps are appended to a persistent local queue on disk.
• When network connectivity is restored, the queue automatically drains in chronological order without losing player progress.

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🔀 Conflict Resolution Strategies (CloudMergeStrategy)

When syncing between multiple devices:

Strategy	Behavior
HighestProgressAndLatestTimestamp	Takes the highest progress value per achievement and the most recent unlock timestamps (Union merge).
UnionUnlocks	Merges unlocked sets from both client and cloud; never revokes an earned achievement.
ServerWins	Overwrites local client state with the authoritative server payload.
ClientWins	Pushes local client state as authoritative to the server.