sqlite-sync-core 0.5.0

Universal SQLite Synchronization Core - A dependency-grade, local-first, offline-first SQLite synchronization primitive

sqlite-sync-core

A production-grade, turn-key synchronization system for SQLite.

sqlite-sync-core provides a powerful, local-first synchronization engine that works seamlessly across multi-peer networks. It handles the "hard parts" of sync (vector clocks, causality, delta bundles, and conflict resolution) while providing a simple, turn-key interface for developers.

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🚀 Turn-Key Synchronization

You can launch a full synchronization node in one command. No infrastructure required.

16-Second Setup (CLI)

# Install the package
pip install sqlite-sync-core

# Start a node and sync the 'tasks' table automatically
sqlite-sync start --db app.db --name Device-A --tables tasks

Automatic Multi-Peer Sync

Nodes automatically discover each other on the local network (P2P) and synchronize state in the background without any manual peer configuration.

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🏗️ Enterprise Features

• Multi-Peer Orchestration: Automatically scales sync across N devices.
• P2P Discovery: Zero-config peer-to-peer discovery on LAN.
• Automatic Resolution: Configurable strategies like Last-Write-Wins and Field-Level Merge.
• Schema Evolution: Built-in migrations that sync across the network.
• Transport Agnostic: Works over HTTP, WebSockets, or file transfer.

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Technical Usage (Library)

Initialize a Node in Code

from sqlite_sync import SyncNode

node = SyncNode(
    db_path="app.db",
    device_name="MobileApp",
    sync_interval=10  # Sync every 10 seconds
)

await node.start()
node.enable_sync_for_table("users")

Safe Schema Migrations

# Safely add a column that will sync to all other peers
sqlite-sync migrate --db app.db --table tasks --add-column priority --type INTEGER

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Core Invariants

#	Invariant	Description
1	Causal consistency	Vector clocks ensure the correct order of operations.
2	Deterministic Replay	Identical sets of operations always result in identical state.
3	Conflict Tolerance	Detects and resolves conflicts explicitly and safely.
4	Offline-First	Entirely local-first design; works without cloud or internet.

2. Generate a Delta Bundle

# To be sent to Peer B
bundle_path = engine.generate_bundle(
    peer_device_id=peer_b_id,
    output_path="delta.db"
)

3. Import and Detect Conflicts

# On Peer B
result = engine.import_bundle("delta.db")

print(f"Ops Applied: {result.applied_count}")
print(f"Conflicts Detected: {result.conflict_count}")

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Core Invariants

#	Invariant	Description
1	Append-only	Operation history is immutable.
2	Causal consistency	Hybrid Logical Clocks (HLC) ensure correct partial ordering and wall-clock correlation.
3	Deterministic	Replay results are identical across all replicas.
4	Field-Level Merge	"Smart" LWW resolution merges concurrent non-conflicting field updates.

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Architecture

┌─────────────────────────────────┐
│     Your Sync System / App      │
└───────────────┬─────────────────┘
                │ Uses
┌───────────────▼─────────────────┐
│       sqlite-sync-core          │
│  (Logging, Bundling, Clocks)    │
└───────────────┬─────────────────┘
                │ Persists to
┌───────────────▼─────────────────┐
│         SQLite Database         │
└─────────────────────────────────┘

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License

AGPL-3.0 for Open Source. Contact [e-mail] for commercial licensing.

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Built for developers who need a reliable sync foundation.