True solo mining: how a block reward is paid straight from the coinbase

On a true-solo pool, the reward for a block you find is written to your own address in that block's coinbase transaction, so the pool never holds it. This explainer covers how that works, why the coinbase normally has other outputs too, such as a pool's fee and the SegWit witness commitment, and how to check a payout yourself.

Category: Mining and the Network · Published 2026-10-28

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What "true solo" means (and what custodial "solo" doesn't)

Solo mining means that when you find a block, the block reward is yours, instead of being shared out in small, steady payouts with thousands of other miners. But the word "solo" gets stretched. A pool can be solo in how it shares rewards and still custodial in how it pays: if the blocks it finds pay an address the operator controls, the operator then has to forward your share, and you are trusting a third party to do it. Ordinary pooled mining works that way too: the block reward goes to the pool, which then pays its miners.1

A true-solo pool removes that step. There is no shared operator wallet for the reward. Your Stratum username is your own Bitcoin payout address, with or without a worker name after a dot (bc1q…yourAddress.rig1); the text after the dot is only a label for your own tracking.2 When any of your workers finds a block, the reward is written to your address inside the block itself. The pool coordinates work and checks shares; it never takes ownership of the coins it pays you.

How the coinbase pays your address directly

Every Bitcoin block begins with one special transaction called the coinbase transaction, also called the "generation transaction". It has no ordinary inputs: it creates the new coins the block is allowed to issue, collects the fees of the block's other transactions, and pays them to whatever addresses the block's builder chose. This is how all freshly issued bitcoin enters circulation.3

When your miner on a true-solo pool finds a block, the pool has already built that block's coinbase to pay your address: the block subsidy plus the block's transaction fees, less any fee the pool charges. The subsidy has been 3.125 BTC since the April 2024 halving.4 The pool's Bitcoin node then broadcasts the block to the network.1 Because the payout is baked into the block's own coinbase, there is no separate payout step, no balance threshold to reach and no withdrawal request. Once the block is accepted, the reward is assigned to your address on-chain, though it can't be spent for 100 blocks (more on that below). The real source of truth is the block itself, which anyone can look up.

Pool fees and the other outputs in the coinbase

A true-solo pool can't deduct a fee from a balance, because it holds none. If it charges one, the fee has to come out of the block you find, written into the same coinbase as a separate output that pays the pool. Fees vary from pool to pool, so read the one a pool publishes.

Your payout is not the only other output, either. A block that contains SegWit transactions must also carry a witness commitment in its coinbase: an output whose script begins with OP_RETURN, so it can never be spent.5 Put together, a true-solo coinbase pays your address, may pay the pool its fee, and normally carries the commitment, all in one transaction.

Here is a real one. Block 973,413 was mined on 27 October 2026 through a solo pool that publishes a 2% fee.62 Its coinbase has three outputs: 3.07689054 BTC to the finder's address, 0.06279368 BTC (exactly 2% of the total, worked out by us) to the pool, and a zero-value witness commitment. Together they come to 3.13968422 BTC, the 3.125 BTC subsidy plus 0.01468422 BTC of fees.6 The pool never held the finder's share: the split was fixed in the block before it was found.

Don't trust, verify: the coinbase is on-chain

The strongest thing about true-solo payouts is that you do not have to take anyone's word for them. A custodial pool can show you a dashboard number, but from the outside you cannot confirm that it will pay, or that it paid the right amount. With a true-solo payout, the payment is a public Bitcoin transaction.

You can check it yourself in any block explorer:

  • Open the block the pool lists as found and look at its first transaction, the coinbase.
  • Find the output that pays your address (the same one you mined under) and check its amount.
  • Expect other outputs too: the zero-value witness commitment and, if the pool charges a fee, an output paying the pool.
  • Check that the outputs add up to no more than the subsidy plus the block's transaction fees. A block whose coinbase claims more is invalid, so no valid block can overpay anyone.7

Nothing here depends on trusting the pool's word, its database or its uptime. The block is the receipt. This is the "don't trust, verify" principle Bitcoin is built on, applied to mining payouts; how to verify cryptocurrency claims applies it more widely.

Custodial pooled mining vs non-custodial solo

It helps to see the trade clearly, because solo is not "better" for everyone; it is a different bet.

  • Pooled mining (PPLNS / FPPS) pays small, frequent amounts for your shares and smooths out luck. It is usually custodial: the block reward goes to the pool, which then pays miners their portions.1 It suits you if you want a steadier payout.
  • True solo pays nothing until one of your workers finds a whole block; then the reward, less any pool fee, lands at your own address. The variance is huge (see how solo-mining probability works), but it is self-custodial, and the block is yours.

One rule to remember: coinbase coins can't be spent until 100 blocks have passed, about 17 hours at the ten-minute average.3 Until then the reward is immature: it is on-chain and assigned to you, but not yet spendable. That is a network rule that applies to every miner, not a pool hold.8 Solo suits miners who accept the lottery, value self-custody, or have enough hashrate to stomach the swings.

FAQ

Does a true-solo pool ever hold my bitcoin?

Not if it pays in the coinbase. The reward from a block you find is written straight to your own address inside that block, so the pool never controls or stores it. A pool that pays found blocks to its own wallet and forwards your share later is custodial, so check which kind you are using.

Do solo pools charge a fee?

Some do, and the amount varies, so read the fee a pool publishes. On a pool that pays in the coinbase, a fee taken from the block appears as a separate output of that coinbase paying the pool, so you can see exactly what it took in a block explorer.

How do I verify a payout actually went to me?

Open the found block in any block explorer and read its coinbase transaction, the first one in the block. Find the output paying your address and check the amount. Expect other outputs too: a zero-value witness commitment and, if the pool charges a fee, an output paying the pool. The block itself is the proof, so you don't have to trust a dashboard.

Why can't I spend my block reward right away?

Coinbase outputs can't be spent until 100 blocks have passed, about 17 hours at the ten-minute average. The rule stops anyone spending a reward from a block that later turns out to be stale. It applies to every miner; it is not a pool hold.

Is custodial "solo" a scam?

Not necessarily, but it is custodial: the block pays the operator's address and you trust them to forward your share. True solo removes that trust by paying your own address directly in the block's coinbase.

Key takeaways

  • A true-solo pool writes your address into the coinbase transaction of the block you find, so the reward never passes through a pool wallet.
  • A coinbase transaction normally has more than one output: besides your payout it may pay the pool's fee, and it carries the SegWit witness commitment.
  • Its outputs can add up to no more than the block subsidy (3.125 BTC since the April 2024 halving) plus the block's transaction fees.
  • Coinbase coins cannot be spent until 100 blocks have passed, a network rule rather than a pool hold.
  • You can check any payout yourself in a block explorer: the block is the receipt.

Sources

  1. Bitcoin Developer Guide, Mining: solo mining (large payments, higher variance) versus pooled mining (small payments, lower variance); shares against an easier pool target; the block reward paid to the pool, which pays miners per share; getblocktemplate and Stratum, where the pool supplies the coinbase — Bitcoin Project (developer.bitcoin.org)
  2. A solo pool's own setup page: set your username to your Bitcoin address, with or without a worker extension; no pool operator wallets; a published 2% fee (read 28 Oct 2026) — solo.ckpool.org
  3. Bitcoin Developer Guide, Block Chain: the first transaction must be the coinbase (generation) transaction collecting the subsidy plus fees; its outputs cannot be spent for 100 blocks; stale blocks and forks; the merkle root in the header; outputs worth more than inputs are rejected; the two-week (1,209,600-second) retarget — Bitcoin Project (developer.bitcoin.org)
  4. Controlled supply: the subsidy halves every 210,000 blocks, total supply slightly less than 21 million, block 840,000 reached on 2024-04-20 with a 3.125 BTC subsidy, miners paid by fees alone once issuance ends — Bitcoin Wiki
  5. BIP141, Segregated Witness (consensus layer): the witness commitment recorded in an OP_RETURN scriptPubKey (an output) of the coinbase transaction, required when a block contains witness data — Bitcoin Improvement Proposals (GitHub)
  6. Block 973,413 (27 Oct 2026, mined through a solo pool): coinbase with one null input and three outputs, 3.07689054 BTC and 0.06279368 BTC to two addresses plus a zero-value witness commitment, totalling the 3.125 BTC subsidy and 0.01468422 BTC of fees — mempool.space
  7. Bitcoin Core source, validation.cpp: the first transaction must be the coinbase and no other may be (bad-cb-missing, bad-cb-multiple); GetBlockSubsidy halves the 50 BTC subsidy every 210,000 blocks; a coinbase paying more than subsidy plus fees makes the block invalid (bad-cb-amount) — Bitcoin Core project (GitHub)
  8. Bitcoin Core source, consensus.h: COINBASE_MATURITY = 100 (coinbase outputs can only be spent after this number of new blocks, a network rule) — Bitcoin Core project (GitHub)

Some specific claims in this article are scheduled for further source review; citations may be expanded (see our editorial policy).

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