Stratum V2: which pools support it and why it matters for miners

Stratum V2 is the next-generation protocol connecting mining hardware to pools. It adds encrypted communication, a more compact data format, and one feature that changes the power dynamic between miners and pools: Job Declaration, which lets miners build their own block templates instead of hashing whatever the pool hands them. As of late September 2026, Braiins Pool and DEMAND (DMND) fully support Stratum V2 with Job Declaration. Several major pools have joined the SV2 Working Group but have not launched production support yet. This article breaks down what Stratum V2 does, which pools support it, what firmware you need, and whether it is worth switching today.

What is Stratum V2 and how is it different from V1?

Stratum V2 is a complete rewrite of the Stratum mining protocol. Stratum V1, which has been the standard for over a decade, works like this: the pool assembles a block template (chooses which transactions to include), sends it to your ASIC, and your machine searches for a valid hash. You have zero say in what goes into the block.

Stratum V2 changes three things:

1. Encrypted connection. V1 sends data in plaintext. Anyone between your miner and the pool (an ISP, a state-level observer, a compromised router) can see the traffic, modify it, or redirect your hashrate to a different pool without your knowledge. V2 encrypts the channel.
2. Compact binary format. V1 uses JSON text messages. V2 uses a binary protocol that cuts bandwidth usage and latency. On a large farm with thousands of machines, the difference adds up.
3. Job Declaration. This is the part that matters for decentralization. With Job Declaration, the miner (or their firmware) pulls transactions from their own mempool, assembles a block template, and declares it to the pool. The pool still coordinates shares and distributes rewards, but the decision about which transactions make it into the block shifts from the pool operator to the individual miner.

Without Job Declaration, Stratum V2 is still an improvement (encryption + efficiency), but it does not change the centralization equation. The pool still decides block content.

Which pools support Stratum V2 today?

As of September 2026, two pools offer confirmed, full Stratum V2 support including Job Declaration: Braiins Pool and DEMAND (DMND). In May 2026, pools representing roughly 75% of Bitcoin's hashrate joined the open SV2 Working Group (CoinDesk, 2026-05-11), but joining the group is not the same as shipping live support.

SV2 Working Group members per CoinDesk: Foundry, AntPool, F2Pool, SpiderPool, MARA, Block Inc., DMND.

Pool support status changes over time. Check each pool's documentation directly before routing hashrate.

What do I need to use Stratum V2?

Two things must both support the protocol:

1. Your pool needs to offer a Stratum V2 endpoint.
2. Your ASIC firmware needs to speak Stratum V2 on the client side.

For firmware, Braiins OS (the custom firmware from Braiins, available for Antminer S19 and S21 series and some WhatsMiner models) has built-in Stratum V2 support. Stock firmware from Bitmain and MicroBT does not support V2 as of this writing. Some third-party firmwares (such as vnish, LuxOS) may have partial support; check their release notes for your specific model.

Steps to switch:

1. Flash Braiins OS (or compatible firmware) onto your ASIC.
2. In the firmware settings, point the pool URL to the pool's Stratum V2 endpoint.
3. If the pool supports Job Declaration, enable it in the firmware settings and make sure your machine is connected to a Bitcoin full node for mempool access (or the firmware handles it internally).

If your firmware does not support V2, the ASIC will fall back to V1 automatically when connecting to a V1-only endpoint. No hashrate is lost during the switch. You can test V2 on one machine before rolling it across a farm.

Does Stratum V2 affect my earnings?

No. Stratum V2 does not change the payout scheme, the pool fee, or the block reward. Your earnings are determined by your hashrate, the pool's fee, and the payout model (FPPS, PPS+, PPLNS, etc., all listed in the POOL BTC comparison).

What V2 can improve:

• Slightly lower stale share rate due to the more compact protocol and lower latency. On a fast connection this difference is negligible; on a high-latency or bandwidth-constrained connection it can matter.
• Protection against hashrate hijacking (man-in-the-middle attacks), which is a real risk on V1 especially in shared hosting environments.

Why does Job Declaration matter for Bitcoin?

Right now, a handful of pool operators decide which transactions go into the majority of Bitcoin blocks. If a pool wanted to exclude a specific transaction or a specific address, its miners would have no technical ability to override that decision under Stratum V1.

Job Declaration flips this. When miners build their own templates, the pool cannot unilaterally censor transactions. Even if a pool operator received a court order to exclude certain transactions, miners using Job Declaration could include them anyway, because the template comes from the miner's own mempool.

This is not a theoretical concern. As Bitcoin block space becomes more valuable and regulatory attention increases in major mining jurisdictions (the US, China, Kazakhstan, Russia), the question of who controls block content becomes more practical with each passing year.

For an individual miner, Job Declaration does not change your income. For the Bitcoin network, widespread Job Declaration adoption would make transaction censorship by pools technically infeasible.

How does Stratum V2 relate to pool custody models?

Two separate dimensions of miner independence:

A pool can support Stratum V2 while still being custodial (your block template, their wallet). Or a pool can be non-custodial while using Stratum V1 (their block template, your wallet). The two features solve different trust problems.

For a deeper comparison of pool fees, payout schemes, and minimum thresholds, see the POOL BTC comparison table and miner ranking.

FAQ

Do I lose hashrate when switching to Stratum V2?

No. The protocol change does not affect your ASIC's hash rate. You may see a small reduction in stale shares due to lower latency, which slightly increases effective hashrate.

Can I use Stratum V2 with stock Bitmain firmware?

Not as of September 2026. You need Braiins OS or another firmware that supports the V2 client. Check your firmware vendor's documentation.

Is Stratum V2 the same as Stratum V2 Reference Implementation (SRI)?

SRI is the open-source reference implementation of the Stratum V2 protocol, maintained by a community working group. Pools and firmware vendors can implement V2 using SRI or build their own implementation. The protocol spec is the same either way.

Does POOL BTC support Stratum V2?

POOL BTC is a comparison site, not a mining pool. We do not operate mining infrastructure. We track and report which pools support which features. See the table above for current Stratum V2 support status.

Will Stratum V2 become mandatory?

There is no mechanism to force pools to adopt V2. Adoption is driven by miner demand and competitive pressure. If miners increasingly choose V2-supporting pools, other pools will follow. If miners do not care, adoption will stay slow.

Where can I learn more about the Stratum V2 protocol specification?

The full specification is maintained at stratumprotocol.org. The SRI code is on GitHub under the stratum-mining organization.

This article contains referral links to mining pools (marked as sponsored). We may receive a reward if you register through them. This does not change the figures or the order of rows in the tables: the terms are taken from the pools' official pages.