The debate between Core and Knots is sweeping the Bitcoin community, as node operators weigh the stability of Core against the advanced anti-spam features of Knots.
If you’re new to Bitcoin, or the only sats you hold are in an ETF or a centralized exchange, you’d be forgiven for not knowing about the Core vs. Knots debate and the entire OP_RETURN saga. But if you have been through a few cycles, have HODLed like a champ, and are still confused, it’s time to pay attention. The 2025 “spam wars” are showing all the signs of the block size wars from almost a decade ago, and the situation is quickly getting ugly.
Just like the block size wars, the spam wars are also said to be a fundamental ideological clash over Bitcoin’s core principles. This includes the debate of scaling versus decentralization and whether network capacity and ease of use should be prioritized over a simpler, permissionless protocol.
Supporters of Bitcoin Core, the long-standing reference implementation, and Bitcoin Knots, an increasingly popular alternative maintained by developer and CTO at Ocean Mining, Luke Dashjr, are at odds. It appears that the conflict is escalating.
Core vs. Knots: What’s Happening?
The core of the controversy is Bitcoin Core’s planned removal of the 80-byte limit on OP_RETURN data. This change is scheduled for its upcoming v30 release in October 2025.
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This technical change, which is intended to increase flexibility and unlock new use cases for embedding data on Bitcoin’s blockchain, is strongly opposed by Knots backers. They argue that it transforms the main network into a place for non-financial transactions and spam.
Core developers, such as Peter Todd and Jameson Lopp, claim the change supports broader innovation, like digital art and document verification. They support the right of everyone to use the Bitcoin blockchain as they see fit, without having governance or morals imposed on them. Lopp posted:
“I truly detest politics. Thus I have little patience for those who try to impose traditional governance models onto Bitcoin. If you don’t like anarchy, you’re free to leave.”
Knots supporters such as Samson Mow and Luke Dashjr warn that the upgrade risks bloating the blockchain, undermining Bitcoin’s neutrality, and weakening its monetary purpose.
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“What do you think will happen now that Core is opening the floodgates to spam, and essentially endorsing it? (No matter what they say, that’s how spammers will take it.) Any chance we have of making Bitcoin a success will go out the window – unless the community takes a clear stand and rejects the change.”
Dashjr warned:
Network Philosophy and Neutrality
The Core vs. Knots dispute highlights deeper ideological rifts about the function of Bitcoin. A key question is whether Bitcoin should remain a strictly monetary settlement layer or if it can be allowed to evolve to serve more experimental on-chain data needs, as long as fees are paid.
Core’s apparent policy shift is seen by some as a relinquishment of its gatekeeping role, which would allow any use case as long as the user pays. Knots supporters, however, emphasize control with features like anti-spam protection and argue that the removal of data caps could centralize power and threaten scalability.
Miners and relay service operators play a key role, determining which transaction types end up in blocks and how the network responds to different software preferences. Node operators have increasingly moved to Knots; its share of the network doubled over a six-week period in May-June 2025 and has now reached about 17% of all Bitcoin nodes. This is a sign of growing protest and potential fragmentation ahead of Core’s v30 launch.
Heading toward What?
Although a hard fork has not yet occurred, mounting tensions and the possibility of blocks or transactions being rejected by different software clients are bringing back memories of the 2017 SegWit split.
The Core vs. Knots scenario also brings up another fundamental issue regarding the true decentralization of the Bitcoin network: how many of Bitcoin’s supporters run their own node? A post was made by Dashjr:
“Bitcoin’s greatest threat to survival is that far too few people are using a full node. For Bitcoin to work, at least 85% of economic activity needs to do so.”
With technical, political, and philosophical stakes involved, October’s Core v30 release may define the next era of Bitcoin development and decentralized consensus. This will determine whether software diversity serves to strengthen Bitcoin’s resilience or results in an outright chain split.
