Polkadot JAM by Parity Technologies / Web3 Foundation: status and timeline

Polkadot JAM

Turn Polkadot from a hub for a fixed set of chains into a shared, permissionless computer with very high data and compute capacity, while keeping the security of one large validator set.

ProtoStage 2 of 5

Pre-audit Gray Paper; clients working toward first conformance milestone. Parachains to JAM targeted 2027.

Updated 25d agoChecked 11 Oct0 updates this week

Milestones

Next · Independent clients pass the first conformance milestone (M1)

Polkadot mainnet launches26 May 2020Complete.
Parachains go liveDec 2021Complete.
JAM Gray Paper unveiled at Token2049 DubaiApr 2024Complete.
DOT holders approve JAM in a near-unanimous voteMay 2024Complete.
First full 1,023-node JAM network run on the Toaster2025Complete.
Independent clients pass the first conformance milestone (M1)Target 2026Current milestone.
Parachain functionality moves to a JAM serviceTarget 2027Not yet reached.

Most important updates

Upcoming

2026Independent clients pass the first conformance milestone (M1) (next)
2027Parachain functionality moves to a JAM service

Current obstacles

No mainnet date yetDOT holders approved the plan in 2024, but production waits on the final spec, audits and conforming independent clients; Parity targets 2027 for parachains.
Independent clients must agree exactlyAbout 43 teams announced clients in late 2025; about 15 submitted for the first milestone by January 2026. Each must match the spec byte for byte.

Physics limits

Results must stay available to be trustedAnyone must be able to re-check any result, so its data has to be stored and served. Erasure coding cuts copies, but bandwidth between validators caps throughput.
Parallel only when tasks don't collideWork splits across cores only if tasks touch separate data. Anything that needs the same state at once must queue in the shared accumulate step, as in any distributed computer.
More validators, slower agreementByzantine-fault-tolerant voting needs messages among about 1,000 validators every block. A bigger set is harder to corrupt but takes more communication per block.

How it works

4 parts

Refine

Heavy work in parallel

Work packages are spread over up to 341 cores; a small validator group runs each one in isolation and posts the result to shared data storage.

Accumulate

A short step updates the state

All validators then run only the brief 'accumulate' step that merges results into the chain's state, so the costly part never runs everywhere.

Services

Parachains become one service

Anyone can deploy a service, code that processes work on cores. Today's parachain system becomes one such service, so current chains keep running.

PolkaVM

A RISC-V virtual machine

Code compiles to RISC-V and is recompiled ahead of time into native machine code, running untrusted programs fast with predictable costs.

Spec sheet

Spec	Polkadot JAM
Data availability (design)	About 850 MB/s^R (reported)
Compute capacity (design)	About 150B gas/s^R (reported)
Maximum cores	341^R (reported)
Validators in a full network	1,023^R (reported)
Implementer prize pool	10M DOT^R (reported)

^R reported by the company

Update log

4 updates

About Parity Technologies / Web3 Foundation

The team behind Polkadot JAM

Parity Technologies / Web3 Foundation

Polkadot, JAM, PolkaVM, Polkadot SDK

Parity Technologies (London) builds the core software of Polkadot, a blockchain where many chains share one set of validators; the Swiss nonprofit Web3 Foundation funds the ecosystem. Both were founded by Ethereum co-founder Gavin Wood, who is now redesigning Polkadot as JAM.

Polkadot 2.0 is live: asynchronous backing, Agile Coretime and elastic scaling are all shipped.
JAM, a RISC-V compute layer to replace the relay chain, has client teams chasing a 10M DOT prize; parachains move onto it in 2027.
DOT supply is now capped at 2.1B; yearly issuance fell by more than half on March 14, 2026.

parity.io (opens parity.io)Company profile →

Founded: 201511 yrs
Headquarters: United KingdomSwitzerland
Status: Private
Valuation: private
Raised: $187M2 rounds
Last round: Private DOT token sale · $43MJul 2020
Works in: CryptoBlockchains (L1s)
Coverage: 1 program · 5 updateslatest 25d agochecked 11 Oct
People: Gavin WoodFounder; CEO of Parity TechnologiesRobert HabermeierPolkadot co-founder

Spec

Polkadot JAM

Data availability (design)

About 850 MB/s^R (reported)

Compute capacity (design)

About 150B gas/s^R (reported)

Maximum cores

341^R (reported)

Validators in a full network

1,023^R (reported)

Implementer prize pool

10M DOT^R (reported)

Polkadot JAM

Milestones

Most important updates

Upcoming

Current obstacles

Physics limits

How it works

Heavy work in parallel

A short step updates the state

Parachains become one service

A RISC-V virtual machine

Spec sheet

Update log

Wed 16 Sep

Tue 30 Dec 2025

May 2024

Thu 18 Apr 2024

About Parity Technologies / Web3 Foundation

Current obstacles

Physics limits

How it works

Heavy work in parallel

A short step updates the state

Parachains become one service

A RISC-V virtual machine

Spec sheet

Update log

Wed 16 Sep

Tue 30 Dec 2025

May 2024

Thu 18 Apr 2024

About Parity Technologies / Web3 Foundation