Today’s quiet mempool isn’t a danger—the subsidy still secures the chain—but the new unlimited-blob rule is permanent and will let the subsequent spam wave stuff blocks, driving up disk, RAM, and bandwidth costs until only datacentres can afford to run nodes. Meanwhile fast off-chain payment networks are on track to reach global scale within a couple of years, so real payment traffic—not chain-bloating uploads—will feed the fee market once the subsidy is gone; if we don’t keep block weight in check now, we’ll end up with Ethereum-style centralised validation just as those fees finally arrive.
Discussion
Why unlimited OP_RETURNs will weaken #Bitcoin
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That’s simply not true because a block can not be larger than 4mb and we have a block time of ten minutes. This rule is written in stone!
When we say “the cap is X,” we’re talking about the consensus block-size limit—nothing else. Un-capping OP_RETURN makes it normal for every block to slam into that limit with random data, and once that feels routine, the most “logical” follow-up from Core is to raise the block size again. Meanwhile, the most “logical” move from alternative node software will be to clap back by filtering off-curve fake pub-key blobs—because if we’re playing Whac-A-Mole, we might as well bring a bigger mallet.
You cannot raise the block size because it would require a hard fork.
My understanding is that we have 4mb max block size and if 1 transaction is 4mb they will have to pay massive fees because the bigger the transaction the more fees they have to pay.
There is a huge cost to spam.
I am not worried about this
Fees are set by price-per-byte, not by “big transaction = big fee.”
When blocks aren’t full, the price floor is tiny, so a blob that fills an entire block can ride in for that same low rate—cheap for the sender, but every node must download and keep those extra megabytes forever.
It's sat/ vb and if op return size is bigger, it's more vb. Right ?
Exactly—they pay a one-off fee in the low hundreds to a few thousand dollars, then that blob sits rent-free on every full node’s disk forever.
