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What is the simplest way to send bitcoin without fee (fee=0)? It seems that many wallets (including Bitcoin Core 24.0.1) do not permit users to set 0 fee for a transaction.

Greg Tonoski
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    Does this answer your question? [How can I avoid paying transaction fees?](https://bitcoin.stackexchange.com/questions/67057/how-can-i-avoid-paying-transaction-fees) – RedGrittyBrick Jan 23 '23 at 13:13
  • Mine a block or [have a friend mine the block](https://b10c.me/blog/007-spending-p2tr-pre-activation/). – Mercedes Jan 23 '23 at 17:08
  • For what purpose would a 0 fee be practical? If you are the one mining the block setting a higher fee would actually benefit your mempool fee reward theoretically, also you wouldn't easily be able to permit access to these fees as they would be abused by anyone trying to lower their fee. So its some kind of a permission-ed setup that is not easily automate-able and lowers your block reward if used at scale. – Poseidon Feb 08 '23 at 17:57

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Full nodes do not propagate transactions that offer less than the minimum relay transaction fee. By default, this setting is 1 sat/vB. If you were to create a transaction with a lower feerate and submitted it on the open network, it would probably not reach the miners.

You would need to convince a miner that they should include your transaction and give it to them directly. This is extra work for the miner and you're not providing any monetary incentive as the fees are set to zero. There is little reason for a miner to acquiesce to such a request.

The simplest way would probably be to try and build a public movement that convinces one or multiple miners that they should generally set their minimum feerate to zero. People have tried that a few times already, it does not seem to have a lot of support.

To build a transaction with zero fee, you would first configure your own node to permit a feerate of zero (to allow your own node to propagate it). I don't think your wallet will ever build a zero-fee transaction, so you'd probably have to build it manually with createrawtransaction. There may be other libraries that make this easier, but I'm not sure anyone has bothered because such transactions are usually not processed by miners today.

Murch
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I found that the simplest way to send bitcoin without fee (fee=0) is offered in GUI in Electrum. The createrawtransaction RPC in Bitcoin Core is more complex due to manually assembling hex string of a transaction.

Greg Tonoski
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  • And did you ever see any of these transactions confirm? – Murch Feb 09 '23 at 02:08
  • Yes, there is an example of the recent 0 fee transaction on the Bitcon mainnet: https://mempool.space/tx/be62f5622efdb92c1a6c2d74dca5f65f54ca913d5291234b5fc23ea4490d6734 – Greg Tonoski Feb 09 '23 at 08:36
  • I hadn’t seen this one, but the exceptionality of transaction with 0-fee getting confirmed even sparks debates on social media. What I meant to ask was whether you have seen any of _your_ transactions get included without fees, or expect that to work. I’ve looked at the mempool and blockchain multiple times in the past years and there always are megabytes of txs waiting, but even empty blocks never pick these up (except when it looks like the miner did it for themselves or as part of a gag). – Murch Feb 09 '23 at 12:05
  • Your transaction actually underscores my perception: on 22nd of December [over 60 MvB of transactions bidding less than 1 ṩ/vB](https://jochen-hoenicke.de/queue/#BTC,3m,weight,0) were waiting for confirmation, yet even this block that included a 0-fee transaction did not fill up the rest of the block with other transactions paying 0-fee.—It stands to reason that the miner manually greenlighted this single transaction. – Murch Feb 09 '23 at 12:11
  • There has been my own 0 fee transaction finalized (included in blockchain) in the Testnet. I haven't attempted the same on the mainnet. – Greg Tonoski Feb 09 '23 at 13:41
  • Another example: tx 1a31c1359f408ce65f9b305d3ebd5c0ef32bc8a62c257ecf4cd537982375bafd – Greg Tonoski Feb 21 '23 at 09:01
  • Testnet has a much more lenient mempool policy. I'm not sure what you're trying to show with your examples. They're so seldom that it fits well with miners occasionally manually including one or another. – Murch Feb 21 '23 at 12:45