JAM stands for Join-Accumulate Machine, a next-generation protocol for Polkadot.
Polkadot JAM, short for Join-Accumulate Machine, is a new design being developed to eventually replace the current Polkadot relay chain. Its name comes from a larger concept called CoreJAM, which stands for “Collect, Refine, Join, Accumulate.” With JAM, the “Collect” and “Refine” processes happen off-chain (outside the blockchain), and only the “Join” and “Accumulate” steps are performed directly on-chain. This setup keeps the chain efficient without losing its flexibility and computing power.
The existing Polkadot system works by using a central relay chain that connects and secures many smaller blockchains called parachains. This setup has been effective so far, but it can slow things down, especially when trying to introduce new features or make technical changes. That’s because most upgrades require approval from the whole network and coordinated updates across all parts, which takes time and effort to complete.
To solve this, JAM brings in a new approach: a permissionless and modular system. Anyone can build and launch new apps, services, or even entire blockchains on Polkadot without waiting for approval.
JAM is designed to do everything the relay chain does, but in a more flexible and developer-friendly way. It still provides Polkadot’s shared security and decentralization, but it removes the rigid structure that tends to slow development down. With JAM, the network becomes more like a permissionless computing platform where you can build, launch, and manage services independently without needing changes to the core protocol.
One of JAM’s most important upgrades is how it supports rollups directly at the protocol level.
Rollups, like optimistic rollups and zero-knowledge proofs, handle lots of computations outside the main blockchain and then send the final result back to the chain for validation. In most blockchains, rollups need extra infrastructure, but JAM builds rollup support right into the network itself. This lets you scale your apps without needing to set up external tools.
Even with all these new features, JAM stays true to Polkadot’s commitment to strong security. JAM still uses validators and cryptographic proofs to ensure that every piece of computation is correct. Additionally, because of how well-integrated everything in the network is, JAM saves you from having to set up additional tools, which may be easily targeted by security breaches. This makes the system not just simpler, but also safer.
In the current Polkadot system, major changes often require on-chain governance and system-wide upgrades. This slows things down and creates bottlenecks. With JAM, you can make changes to individual services whenever you want without needing to upgrade the whole network.
JAM’s architecture is also built for parallel execution. It can handle many services running at once without slowing down. Through what is called a coretime system, JAM lets your services scale up or down based on how much computing power they need. This means that heavier apps can get more resources when needed, while lighter apps can run without wasting energy or space.
Instead of updating the system in parts, JAM will be launched as one big, unified upgrade that improves performance and scalability across the entire Polkadot network.
Overall, JAM combines the best parts of Polkadot with a new architecture that’s more open, more scalable, and easier to use. It introduces a more streamlined way for you to build blockchain apps, removes the need for constant upgrades, and gives you more power and flexibility. It turns Polkadot’s vision for the future into reality: a platform that’s faster, more streamlined, and built to power the next generation of Web3.
