Aptos brings a paradigm shift to Web3 through better technology and user experience. As the lowest-latency, highest-throughout blockchain in the market, we’re empowering developers to build efficiently and create the best applications.
Let’s be clear - the biggest ‘why’ in Why Aptos is all of you! The Aptos Community. Our network thrives because of the dedication of our builders and creators.
Along with the community, powerful technology is another Aptos superpower. This post outlines the innovations driving Aptos to redefine Web3 for more meaningful use. These innovations work together for a seamless experience for developers and users. Whether you are easily developing with the Move language or benefiting from tech-backed user safeguards, a smooth experience is what Aptos delivers.
1. The Move Language for Better Building
Move on Aptos creates a better developer experience for scalable, future-proof applications. Move, along with the Aptos framework, improves builder efficiency by intentionally removing unnecessary complexity that often limits developer accessibility.
Move is an expressive and accessible programming language emphasizing security and designed for safe asset management. Move brings to Web3 what Rust brought to infrastructure development – a safe, fast, and expressive method for mapping interactions.
The Aptos blockchain natively integrates the Move language. Aptos and Move share many of the same core design principles to make Aptos the home for efficient, enjoyable Move development. Move was initially designed for the predecessor of the Aptos blockchain. This relationship ensures existing Move developers can seamlessly build on Aptos and new Move developers benefit from the documentation, guides, and examples that predate Aptos.
Aptos has improved the Move ecosystem substantially by adding multiple features at both the language and the framework levels. Namely refined security architecture, detailed and configurable gas metering, code upgradability, large-scale tables, resource accounts, and more. Beyond that, the Move Prover, a formal verifier for Move smart contracts, provides additional safeguards for contract invariants and is actively extended at Aptos.
Many of the original researchers and developers of the Move language continue to build within the Aptos ecosystem, enhancing the language and the Move community. The Move language has been tested and proven over four years to be secure and production-ready.
2. Block-STM for More Programming Freedom
Block-STM is a new parallel execution engine for smart contracts built around the principles of software transactional memory and optimistic concurrency control for Aptos. This novel approach to transaction parallelism allows for faster transaction processing without impacting the developer experience.
Unlike parallel execution engines that break transaction atomicity by requiring upfront knowledge of the data to be read/written, Block-STM enables developers to code without limits and achieve higher throughput and lower latency for real-world use cases.
Developers can easily build highly parallelized applications using Block-STM. Block-STM supports richer atomicity than other parallel execution environments that often need to split operations into multiple transactions (breaking logical atomicity). This enhances the user experience through lower latency and better cost efficiency.
3. On-chain Governance and Decentralization
To support a truly decentralized and permissionless Layer 1, Aptos has built-in on-chain governance that enables seamless network and VM configuration changes. Aptos Incentivized Testnet 3 and Mainnet demonstrate this.
On Mainnet, this improved the network’s reliability by lowering the "voting power increase limit.” Set to a more aggressive threshold allowed a fast bootstrap of the network. Over 52% of token owners voted on this proposal to help secure our network.
Since genesis, the Aptos community has been able to create and vote on proposals that impact the behavior of the Aptos blockchain. Governance proposals can make changes spanning the epoch duration, or the minimum required and maximum allowed validator stake; modifying flags that result in taking advantage of software upgrades for core blockchain code; as well as upgrades to the Aptos framework modules, a set of core libraries for Move developers, for fixing bugs or enhancing the Aptos blockchain functionality.
4. AptosBFTv4 Consensus for Efficiency
AptosBFTv4 is the first production Blockchain BFT protocol with rigorous correctness proofs. The protocol is optimistically responsive, allowing it to provide low latency and high throughput, taking full advantage of the underlying network. Improving on Hotstuff, Aptosv4BFT reduces the commit latency from 3 to 2 steps, reducing latency by 33% without sacrificing communication complexity (a result published in Jolteon).
AptosBFTv4 is pipelined, similar to a processor, to ensure maximum utilization of resources at each step. As a result, a single node may participate in many aspects of consensus, from choosing which transactions to include in a block, executing another set of transactions, writing the output of another set to storage, and certifying the output of yet another set of transactions. Making the throughput only bounded by the slowest stage (instead of all of them sequentially combined).
The graph above is the Aptos transaction processing life cycle. All stages are completely independent and individually parallelizable.
Implemented with security rigor and upgradeability in mind, the implementation cleanly separates invariants for isolation and effective auditing that enforces a no-forks mentality. The same software stack has been through 4 upgrades and tested on live networks demonstrating the thoughtfulness and robustness of its development process. On its fourth iteration, AptosBFTv4 is the fastest, production-ready Byzantine fault-tolerant consensus protocol.
Aptos ensures overall network uptime even through the downtime of individuals. This is maintained by an on-chain reputation system. The reputation system considers past availability and performance as indicators for the future, which automatically minimizes the negative impact of unresponsive and underperforming validators.
5. Enhanced Safeguards for Consumer Confidence
Aptos accounts support flexible key management, which includes support for features like key rotation, crypto-agility, and hybrid custody models. Key rotation is generally good hygiene and important to prevent long-range attacks that can compromise even multi-party accounts. On other blockchains, rotation is only available by migrating all assets to a new account. The method of decoupling the account from the key enables Aptos to seamlessly add new digital signature algorithms to support public and private key types. The hybrid custody model enables advanced recovery solutions and account management to help bridge the gap between Web2 and Web3.
Wallets can use transaction pre-execution to explain to users the transaction’s outcome before a user signs it. Evaluating transactions before signing mitigates security risks, such as phishing attacks, which have become increasingly common in Web3. To further harden the user experience, the Aptos blockchain constrains the viability of every transaction and protects the signer from unbounded validity through three areas of protection - sequence numbers, expiration time, and chain ID to prevent mistakes/attacks.
Aptos consensus protocol and authenticated storage enable seamless and practical support for light-client protocols enabling a safer and more trustworthy user experience. The Aptos network openly welcomes anyone to connect a fullnode to gain direct access to authenticated data. This emphasizes the Web3 mantra of “don’t trust, verify.” To do this, Aptos builds upon an efficient multicast tree structure to offer a high-throughput, low-latency network for disseminating blockchain state to participants. Participants can process all transactions since genesis or skip the blockchain history entirely and synchronize only the latest blockchain state using waypoints. Light clients can synchronize partial blockchain states, e.g., specific accounts or data values, and enable verified state reads, e.g., verified account balance fetching with BFT timestamps.
6. Modular Architecture for a Future-Ready Network
Aptos has a history of upgradeability. From the ground up, each area within the system was designed with the mentality of modularity and flexibility. This enables the Aptos architecture to support frequent upgrades, which in turn means that the blockchain can quickly adopt the latest technology advancements and provide first-class support for new and emerging use cases.
The Aptos modular architecture design creates client flexibility and optimizes for frequent upgrades with zero downtime - functionality demonstrated in previous mainnet iterations, Testnet, and many internal stress tests. The Aptos blockchain includes embedded on-chain change management protocols to rapidly deploy new technology innovations and support new Web3 use cases.
7. Proposal-Based Reward System
In the Aptos Incentivized Testnet 3, we leveraged voting-based rewards systems for node operators. In this model, once two-thirds of the votes reach the proposer node, consensus under BFT is achieved. This means that one-third of the later votes are not included, and their associated validators are not rewarded.
This can lead to latency competition, and validators closer to the main node cluster tend to be rewarded more. In these circumstances, node operators will move their nodes closer to the main cluster to improve latency and thus increase their staking rewards. This hurts decentralization and geographical distribution as it incentivizes co-location.
We’ve now implemented rewards based on proposal performance as our staking rewards system to promote greater decentralization.
Proposal-based systems have a higher timeout than voting and are arguably less sensitive to cross-region latency. This improves the reward rate of nodes in more remote regions and dampens the effect of geo-distribution, e.g., validators receive less reward if they’re not physically located in the biggest node cluster. Our reward model continues to account for voting behavior, as good voting performance influences proposer election probability.
8. High-Performance Sparse Merkle Tree
Aptos uses the Jellyfish Merkle Tree (JMT) design, which leverages the monotonically increasing version-based key schema to optimize for write amplification on LSM-tree-based (or log-structured merge-tree) underlying storage engines such as RocksDB. JMT reaches a practical sweet spot on the tradeoff between CPU, I/O, and storage footprint, ensuring satisfactory performance without the intractable size of bloated state data on disk.
In addition to JMT as the persisted format of Aptos state, it also has another in-memory, lock-free sparse Merkle tree implementation. This is tailored specifically for caching and parallelization, working with Block-STM to facilitate high-performance global state updates.