From a Single Chain to a Sharded Architecture: How Harmony Uses State Sharding to Solve the Scalability Challenge of Blockchains?

The blockchain network scaling dilemma has, over the past few years, become a core bottleneck restricting the large-scale adoption of decentralized applications. At Ethereum mainnet’s peak, the Gas fee for a single transaction once exceeded $50. High-performance Layer 1s like Solana have repeatedly gone down due to network congestion. The root cause behind these phenomena points to the same issue: traditional single-chain architectures require all nodes to process all transactions. When network demand exceeds a single chain’s capacity limit, slower speeds and higher costs become inevitable.

Sharding offers a different scaling path—splitting the network into multiple parallel processing regions so that transactions can be executed in a distributed manner. Harmony is one of the earlier Layer 1 projects to achieve engineering implementation along this path. Since its mainnet went live in 2019, it has continued running, using a random state sharding architecture that shards network nodes, transaction processing, and blockchain state at the same time. Starting from the limitations of single-chain architectures, the system lays out the core logic of sharding technology, then delves into Harmony’s technical implementation path, and provides an objective evaluation combined with its market performance data.

The boundary of single-chain architecture: why it’s unsustainable for all nodes to process all transactions

In the traditional blockchain architectures represented by Bitcoin and Ethereum 1.0, every full node in the network must download, verify, and store all transaction data on the entire blockchain. The advantage of this design is extremely high security and decentralization—failure of any single node will not affect the network’s overall operation, and tampering with historical data requires controlling more than 50% of the computing power or staked amount at the same time.

However, this “all nodes process all transactions” model has a natural ceiling. Ethereum mainnet’s transactions per second have long remained around 15–30. Visa’s processing capacity is about 24,000 transactions per second. When network demand exceeds its carrying capacity, traders need to compete for limited block space by raising Gas fees. The result is network congestion and a sharp spike in usage costs.

The essence of this contradiction is: security and decentralization require as many nodes as possible to participate in validation, while scalability requires handling transactions as fast as possible—the three together form the classic “impossible trilemma” in blockchain. Under a single-chain architecture, increasing throughput typically means raising the hardware threshold or concentrating validation, which conflicts with the core demand for decentralization.

Therefore, the most core technical proposition for Layer 1 public chains is to improve throughput without sacrificing security and decentralization. Sharding technology is the systematic response to this proposition.

Core logic of sharding technology: from serial to parallel

The concept of sharding originates in traditional database systems. It refers to dividing a large dataset into smaller, more manageable units to improve processing efficiency. In blockchain contexts, sharding means dividing network nodes into multiple subsets (shards). Each shard independently processes the transactions and smart contracts it is responsible for, enabling parallel transaction processing.

Sharding technology can be understood across three dimensions:

Network sharding: Assign all nodes across different shards. Each node only needs to maintain the data and state of its own shard, not all data of the entire chain. This reduces the storage and computation burden of a single node.

Transaction sharding: Route transactions to specific shards based on certain rules (such as the hash of the sending address). Transactions among different shards do not interfere with each other, enabling parallel processing.

State sharding: Split the blockchain’s global state (account balances, smart contract storage, etc.) into multiple subsets. Each shard maintains only its corresponding portion of state. This is the hardest to implement, but it is also the most significant scaling path.

The benefits brought by sharding are linear—theoretically, as the number of shards increases, the network’s total throughput grows approximately linearly. At the same time, because each node needs to process only 1/N of the network’s transaction volume (N being the number of shards), the hardware threshold for nodes can be kept at a relatively low level, thereby protecting the network’s decentralization properties.

But sharding also introduces new technical challenges: How to ensure transaction security and data consistency across shards? How to prevent attackers from concentrating their resources to compromise a particular shard? How to implement cross-shard smart contract calls? These issues form the core difficulties in engineering a sharded public chain.

Harmony’s sharded architecture: engineering implementation of random state sharding

Harmony went live on its mainnet in June 2019 and is one of the earlier Layer 1 blockchains to achieve engineering implementation of state sharding. Its core design philosophy can be summarized as: not only sharding the network nodes, but also sharding the blockchain state—achieving linear expansion across three dimensions: machines, transactions, and storage.

Randomness and security: preventing single-shard attacks

One key security risk for sharded networks is this: if an attacker can concentrate control over a majority of the nodes within a particular shard, they could launch a 51% attack on that shard. Harmony addresses this risk through two mechanisms.

First, each shard is configured with a sufficient number of nodes (currently 250 nodes/shard) to increase the cost for an attacker to control a single shard. Second, Harmony uses a distributed random generation (DRG) process based on a verifiable random function (VRF) that periodically reshards nodes. A node’s shard assignment is unpredictable and cannot be manipulated. This means that even if an attacker controls a shard within a given epoch, they cannot continue maintaining control over that shard in the next reshuffling round.

Consensus mechanism: FBFT and EPoS

Harmony’s consensus layer uses a fast Byzantine fault tolerance (FBFT) mechanism, combined with effective proof of stake (EPoS) for validator selection. FBFT’s core advantage lies in transaction finality—once a block is confirmed, there is no additional confirmation waiting time, which is notably different from other probabilistic-finality consensus mechanisms (such as Bitcoin’s PoW).

EPoS introduces penalty mechanisms and reward allocation optimization on top of the traditional PoS foundation. Validators must stake ONE tokens to participate in block production and validation. EPoS encourages decentralization through fair reward distribution, while penalizing improper behaviors such as double-signing or going offline to maintain network security.

In the v2026.0.0 version of the mainnet, the Harmony team further optimized consensus parameters, aiming to achieve consistent 1-second transaction finality.

Cross-shard communication: atomicity and efficiency

A sharded architecture must solve the consistency problem of cross-shard transactions—when a transaction involves multiple shards, how can it be ensured that all involved shards’ state updates either all succeed or all fail?

Harmony uses an atomic locking mechanism to ensure consistency for cross-shard transactions. At the routing layer, Harmony uses the Kademlia routing protocol for direct communication between shards. Its communication overhead grows logarithmically with the number of shards, rather than linearly. This means that even if the number of shards increases significantly, the efficiency of cross-shard communication will not drop sharply.

Under the four-shard configuration of the mainnet, Harmony’s block generation time is 5 seconds, and cross-shard transactions can be completed within two block times.

Market performance: Harmony (ONE) from a data perspective

As of July 23, 2026, according to Gate market data, Harmony (ONE)’s real-time transaction price is $0.001324. The 24-hour trading volume is $228.9 thousand, the total supply is about 228.9k tokens, the market cap is about $19.6882 million, and its current market cap ranking is approximately #800.

In terms of price performance:

• Past 7 days: ONE price rose from a low of $0.001098 to a high of $0.001753, up +19.60%.
• Past 30 days: Price range is $0.001098 to $0.001753, up +0.45%.
• Past 90 days: Price range is $0.001098 to $0.002684, down -43.48%.
• Past 1 year: Price range is $0.001098 to $0.012476, down -88.57%.

Current market sentiment is neutral, with a -1.12% price change over the past 24 hours.

It should be noted that the above price data points to the trading pair “onetokenburn (ONE)”. Its price differs from the commonly quoted price of Harmony’s native token ONE, which may be due to different exchanges, different trading pairs, or different token standards. Investors should distinguish the data source and token type when referencing related data.

Harmony reached an all-time high of about $0.38 in October 2021, and its market cap once exceeded $5 billion. In June 2022, Harmony’s Horizon cross-chain bridge suffered an attack of about $100 million, delivering a significant blow to ecosystem liquidity, the developer base, and market confidence. Since then, the ONE price has remained in a low-range consolidation for a long time.

Challenges and outlook

Harmony’s technical architecture is quite complete and mature in terms of the sharding roadmap, but its current main challenges are not coming from the technical layer.

Difficulty in ecosystem recovery: The cross-chain bridge attack in 2022 led many DeFi protocols to migrate out of the Harmony ecosystem, causing a major drop in liquidity and developer activity. In a fiercely competitive Layer 1 race, rebuilding ecosystem trust and attracting developers back requires sustained technical investment and community operations.

Competition from the Layer 2 network: Within the Ethereum ecosystem, Rollup solutions (such as Arbitrum, Optimism, Base) have become the mainstream path for scaling. These solutions rely on Ethereum mainnet’s security and liquidity, creating significant competitive pressure on independent Layer 1 public chains.

Reconfirmation of market positioning: In 2026, the Harmony team proposed explorations that integrate with new narrative directions such as decentralized AI infrastructure and DeFi tools (like Autoswap v2). Whether it can find a differentiated market positioning while maintaining the core advantages of sharding technology will be a key variable for its long-term development.

Conclusion

The exploration of blockchain scaling has gone through an evolution path—from theory to engineering, and from simple to complex. As an early practitioner of the state sharding approach, Harmony has continued iterating at the technical level even after nearly seven years of mainnet operation—the release of the v2026.0.0 version is an example.

Sharding technology itself is not obsolete. Even under Ethereum’s scaling narrative dominated by Rollups, the “parallel processing” logic represented by sharding remains one of the fundamental design paradigms for blockchain systems. Harmony’s engineering experience—including random sharding, FBFT consensus, and cross-shard atomic transactions—provides verifiable technical reference samples for the broader industry.

For investors and observers, the value assessment of Harmony needs to distinguish between two layers: the reasonableness of the technical architecture and the sustainability of the ecosystem. The former has already received fairly solid engineering validation in Harmony’s case; the latter still needs further testing in future market competition.

With market sentiment neutral and the price currently in a historical low range, there is a significant gap between Harmony’s technical narrative and its market performance. Whether this gap is a value trough or a value trap depends on the actual progress of ecosystem recovery—which is, itself, an open question that needs to be validated over time.

FAQ

Q: How is Harmony’s sharding technology different from Ethereum 2.0’s sharding solution?

Harmony’s mainnet launched in 2019 and uses a state sharding architecture—not only sharding the network and transactions, but also sharding the blockchain state itself. Ethereum’s scaling roadmap is more inclined toward Rollup-centric solutions, using data sharding (such as Danksharding) to provide data availability for Layer 2, rather than performing state sharding at the Layer 1 level.

Q: How does Harmony ensure security and data consistency across shards?

Harmony ensures sharding security through two core mechanisms: first, a distributed random generation (DRG) process based on a verifiable random function (VRF), enabling unpredictable node shard assignments and periodic resharding; second, an atomic locking mechanism ensures consistency for cross-shard transactions, where all involved shards either update state simultaneously or all roll back.

Q: What are the main uses of the ONE token?

ONE is Harmony’s native utility token. Its main uses include: validator staking to participate in network consensus and block production, paying network transaction fees (Gas Fee), and participating in network governance. Harmony adopts a controlled token issuance mechanism of about 3% annually, and it is paired with a fee-burning mechanism to offset inflation.

Q: What impact did the 2022 Horizon cross-chain bridge attack have on Harmony?

In June 2022, Harmony’s Horizon cross-chain bridge suffered an attack of about $100 million, resulting in a large amount of assets being stolen. After that, many DeFi protocols migrated out of the Harmony ecosystem, causing a significant decline in liquidity and developer activity. The Harmony team then released an asset recovery proposal that does not mint additional ONE, and it has continued upgrading mainnet technology.

Q: What main directions is Harmony currently competing against?

Harmony faces dual competitive pressure: first, from other high-performance chains within the same Layer 1 category (such as Solana, Aptos, Sui, etc.); second, from Layer 2 Rollup solutions within the Ethereum ecosystem (Arbitrum, Optimism, Base, etc.). These solutions rely on Ethereum mainnet’s security and liquidity, posing a significant challenge to the attractiveness of an independent Layer 1 ecosystem.