I have created a transaction with high miner's fee and it is now in mempool (in testnet):


However, it doesn't seem to be confirming. It's already missed two opportunities to confirm. Transactions with much lower miner's fees are going through instead.

Is Bitcoin this random or am I missing something?

  • Another possible cause is that your transaction has an output which is dust, as do several of its ancestors (which are also still unconfirmed). But I am not sure whether the dust rule is enforced by testnet nodes by default. Aug 31, 2018 at 4:50
  • It's confirmed now. Aug 31, 2018 at 13:41

2 Answers 2


Decoding your transaction shows an output:

"vout": [
      "value": 0.00000000,
      "n": 0,
      "scriptPubKey": {
        "asm": "OP_RETURN 68656c6c6f5f776f726c64",
        "hex": "6a0b68656c6c6f5f776f726c64",
        "type": "nulldata"
    }, ...

This might be the reason the miners won't touch it as it may be flagged as non-standard on older nodes. Notice the warning on blockcypher:


Maybe someone can comment on exactly why, as these null_data transactions were made standard on Bitcoin-core 0.9.0, see https://bitcoin.org/en/developer-guide#null-data

  • I wondered about this possibility, but I thought the "standard" checks were disabled on testnet. Also, what with the segwit soft fork, I don't think there could possibly be any miners running 0.9.0 or earlier. Aug 31, 2018 at 4:25
  • Yeah that's what I was thinking as well, it's curious. blockcypher states it is in 71 mempools at the moment, seems low to me.
    – JBaczuk
    Aug 31, 2018 at 4:31

I'm also having problems with testnet which I have not seen before. I'm thinking I may have changed something in my scripts but cannot see what it could be. I'm using multi-sigs for most of the destination addresses

https://tchain.btc.com/2N16FGLa4YpTnCuby9xZT2T2q3rkAxfcX6Y https://tchain.btc.com/5cd81ee81ca48500edb78956aefa6f9f06074a7a7a234579313e5e40cb01b022

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