Definition
Stratum V2 (SV2) is a ground-up redesign of the protocol that connects mining hardware to pools. Where the original Stratum sent unencrypted JSON-RPC text, SV2 uses a compact binary message format wrapped in AEAD encryption based on the Noise protocol framework. The result is lower bandwidth, faster share submission, and protection against the hashrate hijacking and man-in-the-middle attacks that plague plaintext mining traffic.
A modular set of sub-protocols
SV2 is not a single channel but a family of sub-protocols. The Mining Protocol carries jobs and shares between hardware and pool. The optional Job Declaration Protocol lets a miner construct and declare its own block template, and the Template Distribution Protocol feeds that template from a local Bitcoin node. Operators can deploy only the Mining Protocol for a drop-in upgrade, or add the others to reclaim control over transaction selection.
Why it matters for decentralization
Under the old protocol, the pool alone decided which transactions entered every block its miners produced. SV2's declaration path returns that choice to the individual miner, distributing block-construction power across thousands of operators instead of a handful of pools. Combined with header-only mining that slashes the data each device must process, SV2 is one of the most consequential infrastructure upgrades in modern Bitcoin mining.
For the protocol SV2 replaces, see our entry on Stratum V1, and to understand the miner-side template path, read about the Job Declaration Protocol.
In Simple Terms
Stratum V2 (SV2) is a ground-up redesign of the protocol that connects mining hardware to pools. Where the original Stratum sent unencrypted JSON-RPC text, SV2…