Gavin Wood Reveals Polkadot JAM, moving towards a transaction-less decentralized web with 6 second block finality.

Gavin Wood Reveals Polkadot JAM: A Game-Changer in Blockchain

In an industry driven by constant innovation and the quest for scalability, Gavin Wood’s latest announcement about Polkadot JAM (Join-Accumulate Machine) represents a significant leap forward for the blockchain community. With Wood’s reputation as a co-founder of Ethereum and the visionary behind Polkadot, his efforts to address the key challenges of interoperability, scalability, and efficiency within blockchain technology have consistently garnered attention. The introduction of JAM, a new architectural model, underscores Polkadot’s commitment to advancing the Web3 landscape. By promising to enhance the way smart contracts operate and improving parallel computation, JAM is positioned as a game-changer in fostering a more interconnected and efficient blockchain ecosystem.

This article will delve into the intricacies of Polkadot’s Joint Accumulate Machine, beginning with a background on Gavin Wood and the foundational principles of Polkadot. It will examine the persistent hurdles of blockchain scalability and how JAM proposes to overcome these challenges through its innovative architecture and operational model. Readers will gain insights into the technicalities of JAM, including its computational model, consensus mechanism, and the role of parachains in facilitating a new degree of interoperability and parallel processing capacity.

This discussion will extend to the advantages JAM brings to the blockchain domain, its implications for the future of decentralized applications, and how it empowers innovation within the decentralized web, laying out a comprehensive view of what the introduction of this architecture means for the broader landscape of digital consensus and the upcoming release plans for this groundbreaking framework.

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Background on Polkadot and Gavin Wood

Gavin Wood, born in Lancaster, England, completed his education at the University of York, earning a Master of Engineering in Computer Systems and Software Engineering in 2002, followed by a PhD in 2005. His doctoral thesis focused on “Content-based visualisation to aid common navigation of musical audio”. Prior to his significant contributions to the blockchain technology, Wood was a research scientist at Microsoft. His journey into blockchain began as one of the co-founders of Ethereum, alongside figures like Vitalik Buterin and Joseph Lubin. During his time at Ethereum, Wood was instrumental in creating Solidity, a programming language for smart contracts, and conceptualized the Ethereum Virtual Machine (EVM), which executes these contracts.

After leaving Ethereum in 2016, Wood founded Parity Technologies, initially known as Ethcore, which focused on developing core infrastructure for the Ethereum network. The company’s early achievements include the release of the Parity Ethereum software client, written in Rust in 2016, under Wood’s leadership as chief web officer. This period marked a pivotal phase in his career, laying the groundwork for his next major project, Polkadot.

Polkadot, conceived by Wood and further developed by the Web3 Foundation and Parity Technologies, represents a significant evolution in blockchain technology. It operates on a proof of stake mechanism, contrasting Bitcoin’s proof of work, and introduces a novel structure of parachains—individual blockchains that operate in parallel within the Polkadot ecosystem. This design allows each parachain to have its transaction fees and block confirmation speeds, fostering a customizable and scalable multi-chain framework. The introduction of Kusama in 2019, an experimental development environment for Polkadot, further exemplifies Wood’s commitment to innovation and testing in blockchain technology.

Wood’s vision extends beyond conventional blockchain applications. His work with Polkadot and the broader concepts of Web3 aim to decentralize web technologies, promoting an interconnected blockchain ecosystem that supports a variety of industries and applications. This vision is encapsulated in the development of Substrate, a framework for building custom blockchains, and the ongoing expansion of the Polkadot network, which continues to drive forward the decentralization of the internet.

Dr. Gavin Wood’s contributions have not only shaped the foundational technologies of the blockchain industry but also inspired a new era of decentralized applications and innovations. His pioneering work with Ethereum and Polkadot has set the stage for a future where blockchain technology plays a central role in a diverse array of digital and real-world applications, emphasizing interoperability, scalability, and user empowerment.

Challenges in Blockchain Scalability

Current Limitations

Blockchain technology, despite its innovative potential, faces significant scalability challenges that hinder its widespread adoption. Traditional blockchains like Bitcoin and Ethereum struggle with inherent scalability issues due to their design choices, where every participant must validate and store all transactions. This method ensures decentralization and security but limits transaction throughput, leading to network congestion, delays in transaction confirmation, and inflated fees. For instance, Bitcoin can only process around 7 to 10 transactions per second, which is far less than traditional payment systems like Visa, capable of handling thousands of transactions per second.

The scalability or blockchain trilemma highlights a critical challenge: achieving a balance between decentralization, security, and scalability. Increasing scalability often comes at the expense of security and decentralization, requiring trade-offs that complicate the development of a perfectly decentralized, secure, and scalable blockchain.

Polkadot’s Approach

Polkadot introduces a novel solution to these scalability issues through its multi-chain blockchain protocol, which allows various blockchains to interoperate and share information in a trust-free environment. This is achieved by a central relay chain and multiple parachains, each optimized for specific use cases but unified under Polkadot’s unique framework.

The architecture of Polkadot enhances scalability by enabling parallel processing of transactions across multiple parachains. This approach not only increases throughput but also maintains the security and decentralized aspects of the blockchain. The relay chain of Polkadot coordinates cross-chain transactions and enables a consensus mechanism across the platform, which significantly reduces latency and the potential for congestion.

Moreover, Polkadot’s Nominated Proof-of-Stake (NPoS) model and its governance system contribute to a more scalable and efficient network. The NPoS model uses a fraction of the energy consumed by traditional blockchains, and the governance system allows the community to fund and support projects beneficial to the network. These features, combined with the GRANDPA consensus mechanism, ensure that Polkadot can finalize blocks nearly instantly under good conditions, or finalize large quantities of blocks at once when network conditions are less than ideal.

Through these innovations, Polkadot stands out as a beacon of scalability and interoperability in the blockchain landscape, providing a robust platform where developers can build high-performance applications without the typical constraints found in older blockchain architectures.

Introduction to Polkadot JAM (Join-Accumulate Machine)

Definition and Concept

JAM, short for Join-Accumulate Machine, is a prospective design intended to succeed the relay chain in the Polkadot network. Its conceptual foundation, CoreJAM, signifies a computation model based on the principles of Collect, Refine, Join, and Accumulate, which Gavin Wood first described in an RFC. This new model is tailored as a domain-specific chain focusing primarily on roll-ups, enhancing security and generalizing functionalities beyond the current capabilities of Polkadot’s relay chain.

The JAM chain is designed to accept outputs of roll-ups, or bits of computation conducted elsewhere, integrating these outputs into a shared state similar to the existing Polkadot Relay Chain operations. This integration ensures that the output accurately reflects the transformation it is supposed to undergo, thereby maintaining the integrity and correctness of data. Unlike traditional smart contract chains, JAM operates transactionlessly, where all actions are permissionless and undergo a preliminary Refine stage. This stage involves the pre-refinement of input data into work reports, which are then processed into work results and subsequently transferred onto the chain.

Why JAM is Introduced

The introduction of JAM addresses the longstanding dilemma in blockchain technology of balancing ultimate performance and scalability while providing the flexibility to build any use case. Historically, Web3 developers faced a choice between developing smart contracts on Layer 1 (L1) blockchains, which are quicker to write but come with limitations in efficiency, flexibility, and resource competition, or building appchains, which are custom-made for specific purposes but require more development time.

JAM offers a groundbreaking solution by bringing scalability, previously only achievable through rollups, directly to the consensus layer. This model allows developers to enjoy Layer 2 (L2) scalability without the need for separate rollup solutions, providing a rich and flexible environment that supports the development of diverse applications. Furthermore, JAM enhances the existing Polkadot architecture by allowing parachains to run atop a service compatible with the parachain protocol, thus not being limited to the relay chain. This flexibility enables anyone to add a service to the JAM Chain by defining specific entry points such as Refine and Accumulate, thereby broadening the scope and utility of the Polkadot network.

The release plan for JAM involves a detailed pathway towards ratification, conformance, and performance assessments, ensuring that any transition to this new architecture adheres to the highest standards of security and functionality. The Polkadot Fellows play a crucial role in this process, tasked with the ratification of the JAM Protocol, defining conformance and performance tests, and developing compatibility services to integrate seamlessly with the existing Polkadot systems. This structured approach underscores the commitment to a meticulous and thorough integration of JAM, promising to enhance the network’s efficiency and scalability significantly.

Architecture of Polkadot JAM (Join-Accumulate Machine)

Core Components

JAM, envisioned as a distributed computer, is structured to handle almost any task that can be expressed as a service. It significantly simplifies the traditional blockchain architecture by removing user transactions and instead focusing entirely on system services like governance and staking. This architecture is composed of four main components: Refine, Accumulate, and onTransfer, each playing a crucial role in the processing and integration of data within the network.

The Refine component preprocesses input data into work reports, which are then transformed into results during the Accumulate phase. These results are finally transferred across the network, ensuring a streamlined and efficient data handling process.

Differences from Relay Chain

Gavin Wood Reveals Polkadot Jam: A Game-Changer In Blockchain And Difference Between Pokadot Jam And Relay Chains
image courtesy: polkadot insider

JAM’s architecture represents a departure from the traditional Relay Chain used in Polkadot. While the Relay Chain incorporates various functionalities including security and governance within its framework, JAM proposes a more streamlined approach where only the consensus functionality is retained. All other aspects such as security and governance are managed by system-level services, allowing for a more flexible and scalable architecture.

One of the key architectural distinctions of JAM is its domain-specific focus, particularly on handling roll-ups. This design choice not only simplifies the architecture but also enhances its security features, making it less opinionated and more generic compared to the highly specialized Relay Chain. Additionally, JAM supports permissionless code execution and state encapsulation into distinct units called services, similar to smart contracts on a blockchain. These services can be added or modified without central approval, providing a flexible and adaptive framework for developers.

Furthermore, JAM’s design ensures full compatibility with the existing Relay Chain by running it on multiple cores within the new architecture. This guarantees that the transition to JAM will not disrupt current operations but instead enhance the system’s overall efficiency and scalability.

By focusing on fixed parameters and reducing the chain’s upgradability, JAM aims to simplify its architecture while allowing for significant optimizations in network topology and timing. This approach contrasts with the Relay Chain, where frequent upgrades can introduce complexities and hinder performance optimizations.

How Polkadot JAM (Join-Accumulate Machine) works

Gavin Wood Reveals Polkadot Jam: A Game-Changer In Blockchain, How Jam Works
image from polkadot wiki

JAM, short for Join-Accumulate Machine, revolutionizes the Polkadot network by introducing a novel computation model termed CoreJAM, which encompasses Collect, Refine, Join, and Accumulate processes. This model divides computation into two distinct layers: an off-chain layer for massively parallel computation and an on-chain layer for integrating validated results into a coherent state.

Transactionless Design

JAM operates on a transactionless design where traditional user transactions are absent, and all system logic, including governance and staking, resides within system services. This design allows JAM to function efficiently as a distributed computer capable of running almost any task expressed as a service. Services within JAM interact through predefined entry points—Refine, Accumulate, and onTransfer—each defining specific functions and workflows executed within the JAM framework. This setup not only simplifies the blockchain’s architecture by focusing on essential functionalities but also enhances its capacity to handle diverse computational tasks without the overhead of managing user transactions.

Refine and Accumulate Functions

The Refine function, the primary workhorse of JAM, handles largely stateless operations, processing up to 5 MB of data per 6-second time slot and yielding a maximum of 4 kB of compacted data. This function is crucial for the preliminary refinement of input data into work reports, which are subsequently processed into work results during the Accumulate phase. The Accumulate function, on the other hand, is stateful and integrates the output from the Refine function into the chain state. It grants access to JAM’s state, reads storage from any service, writes to its key-value store, transfers funds, and performs other functionalities, with its execution time per output typically around 10 milliseconds.

This dual-function setup allows JAM to massively increase the amount of useful computation that can be done in a decentralized, trust-less manner, spreading computation across many machines working in parallel off-chain while maintaining strong security guarantees and a coherent global state. The Collect-Refine-Join-Accumulate model thus represents a significant evolution in blockchain architecture, enhancing both functionality and scalability while maintaining the integrity and security of the network.

Advantages of Polkadot JAM Architecture

Scalability and Performance

JAM Chain’s architecture leverages Polkadot’s advanced sharding technology and relay chain framework to achieve high throughput and low latency, crucial for robust performance as network usage escalates. By implementing sharding, which divides the network into smaller partitions to process transactions in parallel, JAM Chain significantly enhances transaction throughput and network efficiency. This scalability is vital for supporting a broad spectrum of applications, ranging from finance and governance to gaming, without compromising performance. Additionally, the integration of smart contracts and customizable parachains allows developers to tailor solutions to specific application needs, fostering innovation across various sectors.

Flexibility and Security

The JAM model combines the functionality of Ethereum’s smart contracts with Polkadot’s parachain architecture, providing a framework that supports shared security and native scalability. This integration facilitates a transactionless environment where applications manage transactions independently, supporting multi-core computation for parallel processing of numerous chains and programs. Furthermore, JAM enhances functionality and scalability by natively integrating smart contracts and zero-knowledge rollups (ZK-rollups), and by supporting the UTXO model, similar to Bitcoin’s accounting framework.

Built upon Polkadot’s robust security model, JAM Chain ensures the integrity of transactions and the resilience of the network. It benefits from shared security through the Polkadot Relay Chain, which enhances protection against malicious attacks and ensures the reliability of transactions processed on the chain. This security model is crucial for maintaining trust and integrity within the ecosystem, as it allows for direct exchanges like token transfers without relying on intermediaries.

Future Implications of JAM

The introduction of JAM, a revolutionary approach in blockchain technology, is set to redefine the operational capabilities of the Polkadot network. As a decentralized, cryptoeconomic system, JAM is designed to enhance network efficiency and scalability significantly. This hypothetical upgrade, outlined in the “Gray Paper,” is still in the proposal stages but has laid out a clear path toward its ratification, conformance, and performance assessments.

The Polkadot Fellows are tasked with critical roles in this initiative, including the ratification of the JAM Protocol, defining conformance and performance tests, and developing and deploying compatibility services. These steps are crucial to ensure that JAM integrates seamlessly with the existing Polkadot Relay-chain, facilitating a smooth transition if a full implementation occurs. The proposal’s submission as a “remark call” is a strategic move to gauge community interest and approval for the JAM protocol, emphasizing the decentralized ethos at the heart of Polkadot and inviting community members to actively participate in the network’s evolution.

JAM’s architecture combines Ethereum’s smart contract functionality with Polkadot’s parachain architecture, introducing a transactionless environment where applications handle transactions independently. This setup supports multi-core computation, allowing for parallel processing of numerous chains and programs, which significantly enhances scalability and performance. Furthermore, JAM integrates smart contracts and zero-knowledge rollups (ZK-rollups) natively, supporting the UTXO model similar to Bitcoin’s accounting framework, and introduces the SAFROLE Algorithm to enhance anonymity and minimize forks.

With a target throughput of 850 mb/s, JAM is poised to outperform many existing blockchains, offering a promising future for Polkadot as a scalable and efficient blockchain platform. As development progresses, JAM could lead the path to a new era of blockchain technology, solidifying Polkadot’s position at the forefront of Web3 innovation.

In summary, the future implications of JAM are vast, with the potential to transform Polkadot into a more powerful, scalable, and efficient blockchain platform. The strategic steps outlined for its development and integration highlight a comprehensive approach to ensuring its success and adoption within the broader blockchain ecosystem.

Empowering Decentralized Innovation with JAM

JAM steps in to address limitations in blockchain technology, offering increased flexibility and ease of deployment for developers. It combines Ethereum’s smart contract functionality with Polkadot’s parachain architecture, providing shared security and native scalability. In this environment, applications handle transactions independently and support multi-core computation, allowing for parallel processing of numerous chains and programs.

Opportunities for Developers

Developers benefit from JAM’s integration of smart contracts and zero-knowledge rollups (ZK-rollups) natively, enhancing functionality and scalability. The protocol also supports the UTXO model, similar to Bitcoin’s accounting framework, which is familiar to many developers. Moreover, JAM introduces the SAFROLE Algorithm, a simplified, SNARK-based block production algorithm that enhances anonymity and minimizes forks, and supports XCMP for efficient cross-chain communication. These features are critical for maintaining manageable Proof of Validity sizes and offer developers a robust platform for innovation.

JAM shares similarities with smart contract chains by allowing permissionless code execution directly on the chain and organizing state into distinct encapsulations called services. These services encompass code, balance, and state, resembling the structure of smart contracts. Additionally, JAM introduces the onTransfer function, enabling asynchronous communication between services. Both Accumulate and onTransfer are designed to be executed in parallel, allowing simultaneous processing across different services.

If successfully implemented, JAM could enable a new generation of decentralized applications that are simply not possible on current platforms due to scalability constraints. From high-frequency decentralized exchanges to complex multi-party computations, the use cases are boundless.

Real-world Applications

Polkadot JAM aims to support around 350 cores with a 6-second execution time and 5MB input each, totaling approximately 2.3 Gbps. This results in a 3x increase of the current parachain computation. With an 850 mb/s throughput as the target, JAM positions itself significantly ahead of many other blockchains, with Ethereum processing 1.3 mb/s and Solana at 125 mb/s. After the Solana Firedancer update, the blockchain will be at 1,250 mb/s, yet JAM’s design still leads in performance.

Notably, JAM will be transactionless; all actions will be permissionless and initially undergo a Refine stage. During this stage, the service pre-refines input data, transforming it into work reports consisting of work results. Subsequently, these work results are transferred onto the chain, ensuring a streamlined and efficient process for real-world applications.


The unveiling of Polkadot’s JAM represents a pivotal advancement in blockchain technology, spearheaded by Gavin Wood’s vision for a more scalable, interoperable, and efficient framework. Throughout this article, we explored the foundational principles underlying the JAM architecture, emphasizing its capacity to transcend the current limitations encountered within the blockchain ecosystem. The JAM model, with its unique computational process encompassing Collect, Refine, Join, and Accumulate, showcases a departure toward a transactionless design that significantly enhances the performance and scalability of decentralized applications.

The strategic rollout of JAM, underscored by Polkadot Fellows’ meticulous approach towards ratification, conformance, and performance assessments, illustrates a well-orchestrated effort to integrate this new model seamlessly within the existing framework, promising an evolution in the fabric of blockchain technology.

Reflecting on the wider implications of JAM’s introduction, it’s apparent that this innovative architecture not only solidifies Polkadot’s standing in the realm of blockchain but also signals a transformative phase for decentralized technology at large. By affording developers an unprecedented degree of flexibility and scalability, JAM opens new vistas for application development that were previously constrained by the technical limitations of earlier blockchain models.

This evolution signifies a leap towards realizing the full potential of decentralized systems, underscoring the importance of continuous innovation in shaping the future of digital consensus mechanisms. As the blockchain community anticipates the deployment of JAM, it stands on the precipice of exploring new applications and functionalities that could redefine the interactions within the digital space.


What is JAM in the context of Polkadot?

JAM is designed to be an extensive and somewhat integrated blockchain platform. It aims to merge the smart contract capabilities of Ethereum with the parachain structure of Polkadot to ensure shared security. Additionally, it introduces native ZK-rollups to enhance scalability, a feature that sets it apart from Ethereum, which currently depends on external Layer 2 ZK-rollup solutions for scalability.

What motivated Gavin Wood to create Polkadot?

Gavin Wood’s vision behind Polkadot was to advance the cryptocurrency ecosystem by enabling seamless interactions among various blockchains. This, he believed, would be a significant step towards the development of a decentralized internet, showcasing the transformative potential of cryptocurrency technology for the future of online spaces.

Who founded Polkadot?

Gavin Wood is recognized as the founder of Polkadot, playing a crucial role in its development and establishment in the cryptocurrency world.

How did Gavin Wood contribute to Ethereum?

Gavin Wood, a computer scientist and entrepreneur, significantly impacted Ethereum as one of its co-founders. He was instrumental in developing Ethereum’s proof-of-concept, writing a majority of the code himself. During his time at Ethereum, he also served as the Chief Technology Officer, contributing to its foundational technology and growth.

Disclaimer: The information provided in this article is for informational purposes only and does not constitute financial advice. Investing in cryptocurrencies involves risks, and readers should conduct their own research and consult with financial advisors before making investment decisions. Hash Herald is not responsible for any profits or losses in the process.


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