SpendableStore: A UTXO-based Decentralized Data Store

2026-07-02

AI Summary

Existing blockchain databases struggle to simultaneously achieve decentralization, scalability, and practicality: permissioned chains compromise decentralization, while account-based public chains face performance bottlenecks. This work proposes SpendableStore—a UTXO-based hybrid on-chain/off-chain database that pioneers the use of the UTXO model for general-purpose data storage. By embedding atomic data units, it introduces “spendable data objects” supporting full CRUD operations and incorporates a novel Future-Now Snapshot Isolation mechanism for transaction concurrency control. The design ensures data integrity and ownership directly through blockchain nodes while strictly limiting administrator privileges, thereby achieving genuine decentralization. Experimental evaluation on mainstream mainnets demonstrates up to a 16× throughput improvement over the current state-of-the-art blockchain databases.

Abstract

The literature on blockchain-based databases is divided into permissioned blockchains and permissionless account-based blockchains. However, the former is not fully decentralized, and the latter suffers from challenges in scalability and practicality. We propose SpendableStore, a hybrid on/off-chain database that operates on top of permissionless UTXO-based blockchains as a novel approach to the problem of data decentralization. Our design integrates atomic data units into individual UTXOs to create a new blockchain concept called Spendable Data Objects that perform traditional CRUD operations. The integrity, immutability, and ownership of these Spendable Data Objects are safeguarded directly by the blockchain peer nodes, thus constraining the power of database administrators to achieve true data decentralization. We further support database transactions and propose an isolation mechanism called Future Now Snapshot Isolation to reason about transactional correctness in SpendableStore. We performed experiments on a major blockchain's Mainnet and observed up to 16x better throughput compared to a state-of-the-art blockchain-based database.

Problem

• blockchain-based databases
• decentralization
• UTXO
• scalability
• data integrity

Innovation

• UTXO-based blockchain
• Spendable Data Objects
• decentralized database
• snapshot isolation
• hybrid on/off-chain