Polkadot is Preparing its Biggest JAM Transition Yet

Parity Technologies Sets 2027 Target for JAM Migration

Parity Technologies, a core technical contributor to Polkadot, has announced plans to migrate Parachain functionality to JAM (Join Accumulate Machine), with a production launch targeted for 2027. The move represents one of the most consequential structural changes in Polkadot's history, reshaping the way parachains operate at a fundamental level.

Parity's implementation team will share technical updates through the Polkadot Forum, giving developers and community members a direct line to progress reports as the work advances. The shift from Substrate pallets to JAM services reduces governance friction, since JAM services deploy permissionlessly, similar to smart contracts, whereas Substrate pallets require on-chain governance approval for deployment and updates. That flexibility is central to the case for migration.

From Gray Paper to Active Development

The plan follows JAM's gradual progression from concept to active engineering. In April 2024, Polkadot founder Dr. Gavin Wood released the JAM Gray Paper. Since then, the specification has moved through multiple revisions, with the JAM protocol largely stabilising over the past year.

JAM is supported by a large independent implementor community, which provides meaningful network diversity and reduces the risk of a single team's error affecting the wider network. That decentralised approach to development is a deliberate design choice, and one that distinguishes JAM from earlier Polkadot upgrades.

Developers retain Substrate SDK compatibility and can continue using FRAME for parachain services, but JAM-native services access simplified development models without pallet upgrade coordination overhead. According to the Polkadot Wiki, parachains will remain first-class citizens on JAM, with full compatibility guarantees written into the code. For teams already building on Polkadot, the transition is designed to be gradual rather than disruptive.

With the Hub Migration now complete, key elements of Polkadot's "Second Age" are unlocked, including onward migration from the Polkadot Relay-chain to the Polkadot JAM-chain. The 2027 production target for the parachain-to-JAM migration sits within that broader roadmap, as Parity works through the remaining engineering milestones ahead of a full network transition.

Sources
Parity Technologies: Polkadot Roundup 2025
Parity Technologies: Demystifying JAM
Polkadot Wiki: JAM Chain FAQ