Non-standard >80 byte op_return

Development
1

Bitcoin has two sets of rules. The consensus rules, which all blocks/transaction must comply with. And standard rules which are optional and set by default in Bitcoin Core.

The 80 byte limit for op_return is a standard rule. Node operators can disable it.

I am testing to see if I can get such a non-standard >80 byte op_return accepted by a miner.

Step 1:
Make a long broadcast message with Electrum-Counterparty/broadcast_text.html at master · Jpja/Electrum-Counterparty · GitHub. Need to comment out the line for input length (currently line #80 //print_result("Input text is too long"); return; ).

Step 2:
Create transaction with Electrum. This goes well until broadcasting the tx. The server returns an error Some of the outputs pay to a non-standard script.

Step 3:
Export → Copy to clipboard

Step 4:
Push raw tx with BlockCypher - Push Raw Bitcoin Hexadecimal Transaction | BlockCypher

Step 5:
Wait until confirmed - BTC Transaction 547d2cca830d0a1c7b8105846f192b5f165e196d9721d7e05378f5b79fdef02b | BlockCypher

The last time I tried, the transaction stayed in mempool for a few days. And then dropped out. Did not make it to a block. However, the fee I paid was very low, about 2 sat/byte.

This time I’m using 20 sat/byte. Let’s see if a higher reward convinces a miner to accept it.

2

A similar >80-byte op_return on testnet went through without a problem.

This is as expected, as testnet nodes do not enforce “standard” rules.

https://testnet.xchain.io/tx/d8efb73ebf29c6b77c72ddd2820d6b2013494602bef5c7bd07d4e355c73ca129

3

1 day passed, the tx is dropped from mempool

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To be clear, all we know is that

  1. BlockCypher does not have the tx in their mempool anymore.
  2. No miner has so far included the tx in a block.

In theory, the tx could have been relayed to other nodes which may still keep a copy. There is still a chance that a miner adds the transaction to a block.

This holds true until I spend the input in another transaction, which I won’t do for a while. The fee ratio is 20 sat/byte, significantly more than the current level of 5 sat/byte. A profit maximizing miner is incentivized to include it.