Many valid transactions are not broadcastable by default in bitcoin core to avoid attacks that could harm the network. These would rarely be found in a node's mempool but could, however, be found in blocks because they don't violate any consensus rules.

What transactions fit these criteria?

  • Another one that comes to mind is a transaction with too many unconfirmed ancestors Commented Jul 13, 2020 at 2:01
  • 2
    Hi Pedro, our platform tends to work poorly for questions that preconceive the answer. You may get more interesting answers if you reduce this post to the question portion and post your suggested answer as an answer post. Self-answers are encouraged! This would give other users a better chance to write a comprehensive answer rather than responding to the answer you already preformulated in your question.
    – Murch
    Commented Jul 13, 2020 at 3:40
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    Thanks for the suggestion @Murch , I moved it that part to an answer.
    – Pedro
    Commented Jul 13, 2020 at 8:16

1 Answer 1


The following transactions are not broadcastable with the default bitcoin core configuration but could be found in new mined blocks:

  • Transactions whose fee is smaller than 1 sat/vB (and RBF bumps that increment less than 1 sat/B).
  • Transactions with size greater than 100 vkB (and smaller than ~ 1 vMB)
  • Transactions with outputs amounts smaller than 566 satoshis (dust limit)
  • Transactions that are considered non-standard (I will try to list them because this is a very broad category)
  • Transactions with scriptSigs larger than 1650 B (and smaller than 10kB)
  • Transactions with more than one OP_RETURN output or an OP_RETURN output bigger than 83 B.
  • Transactions with scriptPuKeys of bare n-of-m multisigs, where m > 3.
  • Transactions with scriptPubKeys or ScriptSigs that make the transaction malleable.

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