Stratum V1 vs Stratum V2: What Changes for Bitcoin Miners

Stratum is how miners receive work from a pool and submit shares. Learn how Stratum V1 works today, what Stratum V2 changes, and why V2 is not simply “V1 with encryption.”

Category: Mining and the Network · Published 2026-06-30

Technically reviewed and sourced on 2026-07-05

Your miner doesn’t talk to Bitcoin directly

When you point a miner at a pool, it does not connect to the Bitcoin network directly, and it does not download the blockchain. Instead it holds a single conversation with the pool over a mining protocol, and that protocol is almost always called Stratum.⁶

Stratum is the channel that carries the work the pool wants you to try and the results you send back. Understanding it makes the rest of mining easier to read: why your miner has a username and password field, what a “share” is, why difficulty adjusts, what the TLS option protects, and what newer protocol work like Stratum V2 is trying to change.

This article explains what Stratum is, how Stratum V1 works today, what Stratum V2 changes, and what all of it means for a home miner running a Bitaxe, a small ASIC, or any solo setup.

What is Stratum?

Stratum is the communication protocol between Bitcoin mining hardware and a mining pool.⁶ It handles a handful of specific jobs: the miner subscribes to the pool, authorizes with a username (on SoloLuck, your Bitcoin address) and a password, the pool sends mining jobs, and the miner submits shares back. Along the way the pool sets a per-connection share difficulty and pushes fresh jobs whenever the network moves on.⁶

It helps to be clear about what Stratum is not. It does not change Bitcoin’s proof-of-work rules, and it does not change your solo-mining odds. It is also not the same thing as Bitcoin’s peer-to-peer network: your miner speaks Stratum to the pool, while the pool and the Bitcoin node behind it handle block templates and actually submitting a found block to the network.⁷

A simple way to picture it: Bitcoin mining is repeatedly making guesses against a target. Stratum is the work-order channel. The pool says “try work based on this block template,” and the miner answers “here are the results I found.” The pool builds that template from a Bitcoin node⁷ and checks whether any returned result is good enough to be a real block.

What Stratum V1 does

Stratum V1 is the version in near-universal use today, and existing ASICs and miner firmware support it widely.⁶ A normal session runs in a predictable order:

• the miner opens a connection to the pool and subscribes;
• it authorizes with an address / worker name;
• the pool sends mining jobs describing the work to attempt;
• the miner works and submits shares;
• the pool validates each share; and
• if a submitted result meets Bitcoin’s network difficulty, it can become a valid block.⁶

One point trips up almost every new miner: a share is not a block. A share only proves you did work at the pool’s assigned share difficulty; it is a steady progress signal, not a payout. Pool share difficulty and Bitcoin’s network difficulty are two different numbers, and network difficulty is vastly higher.⁶ In solo mining you are paid only when a share happens to also clear the full network target.

What Stratum V1 doesn’t solve well

V1 works, but it was designed years ago and leaves several things to the pool and the transport layer:

• No built-in encryption. Plain V1 travels in the clear unless it is wrapped in TLS.⁶ TLS can protect the miner-to-pool link from passive observers and tampering, but it does not change the Stratum protocol itself.
• The pool usually builds the block template. In a typical V1 setup the pool decides which transactions go into the block; the miner just hashes what it is given.⁷
• Limited job negotiation. V1 has no standard way for a miner to declare its own work or its own template.
• Text-based messages. V1 uses JSON-RPC framing, which is easy to read but less efficient than a compact binary design.⁶
• Security depends on setup. How protected a V1 connection is depends partly on transport configuration (TLS or not) and on the pool’s implementation.

None of this means V1 is “unsafe.” A plaintext V1 connection on a network you fully control is perfectly normal, and TLS closes the main transport gap. It just means V1 leaves template choice and efficiency on the table — and that TLS alone does not turn V1 into V2.

What Stratum V2 changes

Stratum V2 is a redesign, not a patch.¹ Its specification changes the protocol at a structural level. The main differences:

• Binary protocol. Messages use a compact binary encoding instead of text JSON, which is more efficient on the wire.²
• Built-in encryption and authentication. Security is part of the protocol design rather than an optional TLS wrapper.²
• Separation into sub-protocols, each with a defined role: the Mining Protocol for distributing work and shares,³ the Job Declaration Protocol for negotiating what work is mined,⁴ and the Template Distribution Protocol for moving block templates between a node and the mining infrastructure.⁵
• Miner-selected templates. Through the job declaration flow, a miner or a mining proxy can take part in choosing the block’s transactions instead of always taking the pool’s template.⁴
• Less trust placed in the pool for transaction selection when the job declaration and template flows are fully implemented.⁴

Stratum V2 is not just “V1 with encryption”

This is the most common misread, so it is worth stating plainly. Adding TLS to V1 protects the transport: the bytes between your miner and the pool become private and tamper-evident.⁶ That is genuinely useful, but it is a wrapper around the same protocol.

Stratum V2 changes the protocol structure and the roles themselves.¹ Encryption is only one part of it.² The larger change is how work, templates, and job negotiation are organised, split across the mining,³ job declaration,⁴ and template distribution⁵ sub-protocols. Put simply: TLS-over-V1 seals the envelope; V2 rewrites what is inside it and who gets to decide.

Why miner transaction selection matters

In many V1 pool setups the pool builds the block template, which means the pool effectively decides which transactions a large amount of hashrate will confirm.⁷ Concentrating that choice in a handful of large pools is a recognised centralisation concern for Bitcoin.

Stratum V2’s template and job declaration design lets miners or mining proxies participate more directly in choosing the template,⁴ supported by a template distribution flow from a node.⁵ Done well, that spreads transaction-selection influence back toward individual miners and eases one point of centralisation pressure.

One honest caveat: “V2 supports miner-chosen templates” does not mean every V2 deployment automatically gives every individual miner full, independent control of its own block template. It depends on how the pool, the firmware, and any proxy in between are configured.⁴

What this means for home miners

The practical reality for a home setup today:

• Most miners still connect with V1-compatible pool settings, and that is completely normal.
• Whether you can use V2 depends on ecosystem support: your miner firmware, the pool, and any proxy in between all have to speak it.¹
• If your device only supports V1, you are not missing out on better odds — your odds never depended on the protocol.
• If your firmware supports TLS, TLS is still worth using for V1 privacy on networks you do not fully control.⁶
• For SoloLuck specifically, the setup page is the source of truth for which endpoints are currently offered.

V1, V1 over TLS, and V2 at a glance

A factual side-by-side. “V1 over TLS” is still Stratum V1, just carried inside an encrypted tunnel.

Common misunderstandings

A few myths worth clearing up:

• “Stratum V2 is just encrypted Stratum V1.” No. Encryption is one piece; V2 also changes the message format, the roles, and template/job negotiation.¹²
• “TLS and Stratum V2 are the same thing.” No. TLS is transport encryption you can put around V1; V2 is a different protocol.²
• “V2 automatically means every miner builds their own block.” Not necessarily. V2 enables miner participation in template selection, but the outcome depends on the deployment.⁴
• “A pool that uses V1 is automatically dishonest.” No. V1 is the current standard; using it is normal and says nothing about a pool’s honesty.
• “Changing Stratum version changes solo-mining odds.” No. The protocol version has no effect on proof-of-work probability.⁶

The core point: your Stratum version does not change Bitcoin’s underlying proof-of-work probability. Solo-mining odds are set by your hashrate compared with Bitcoin’s network difficulty⁶ — nothing about V1 versus V2 moves that number.

Where SoloLuck fits

To keep this specific and honest:

• SoloLuck’s current documented endpoints live on its setup page, which is the source of truth for what is offered right now.
• SoloLuck supports plaintext Stratum and, where documented, a TLS Stratum endpoint that protects the miner-to-pool connection.⁶
• SoloLuck’s odds are determined by your hashrate versus network difficulty, not by whether your connection is V1 or V2.⁶

SoloLuck currently documents Stratum V1 endpoints. Stratum V2 is included here as protocol education, not as a claim that SoloLuck supports V2 today.

FAQ

Key takeaways

• Stratum is the protocol your miner uses to get work from a pool and submit shares; it does not change Bitcoin's proof-of-work rules.
• Stratum V1 is the near-universal standard today; a share proves work at the pool's difficulty and is not itself a block.
• Stratum V2 is a redesign: a binary format, built-in encryption, and sub-protocols for mining, job declaration, and template distribution.
• V2's bigger change is letting miners help choose the block template, which can reduce centralisation — but the exact behaviour depends on the deployment.
• Your Stratum version never changes your solo-mining odds; only your hashrate versus network difficulty does.

Sources

1. Stratum V2 specification — stratumprotocol.org
2. Stratum V2 specification — Protocol Overview — stratumprotocol.org
3. Stratum V2 specification — Mining Protocol — stratumprotocol.org
4. Stratum V2 specification — Job Declaration Protocol — stratumprotocol.org
5. Stratum V2 specification — Template Distribution Protocol — stratumprotocol.org
6. Stratum mining protocol (V1): subscribe, authorize, submit, and pool-assigned share targets — Bitcoin Wiki
7. getblocktemplate: how a node builds a block template for mining — Bitcoin Developer Reference

Related educational reading

• Stratum Encryption: What Mining Over TLS Protects
• Mining Pool Latency and Stale Work Explained
• How Mining Pool Hashrate Estimates Work