There's been lots of debate about Core v30 removing the OP_RETURN size/count policy defaults, so I ran the numbers for the latest mempool research report:

mempool research

OP_RETURN Report

A data driven analysis of OP_RETURN usage on bitcoin, revealing that the overwhelming majority of OP_RETURNs are standard, nonstandard usage has no...

There were three big waves of OP_RETURN usage: 2019, 2024, 2025. Nearly all standard transactions. The nonstandard ones are so rare you can hardly see them on the chart. The 2019 Veriblock wave actually put more data on-chain than anything since. People talk about recent OP_RETURN usage like it's unprecedented, but surprisingly it isn't. The important thing is that the spikes in nonstandard OP_RETURNs were in Mar 2024, May 2025, Aug 2025. All before v30 shipped in November 2025. The rate hasn't gone up since. At all. In fact it's come down Runes transactions were standard under the old rules and would even still be standard for #BIP110 (the proposal that's supposedly aims to curb data embedding). If these guys are serious about stopping data they should block runes. TL;DR: v30 recognised what was already occasionally happening on-chain. Nonstandard OP_RETURNs are vanishingly rare, haven't increased post-v30, and the current wave is already cooling off. The data doesn't support the panic. Read the full report linked below 👇

mempool research

OP_RETURN Report

A data driven analysis of OP_RETURN usage on bitcoin, revealing that the overwhelming majority of OP_RETURNs are standard, nonstandard usage has no...

It’s great to see so many people learning the difference between - Bitcoin consensus vs policy - UTXOs in RAM vs disk - Hard vs Soft fork (& chain split)

Instead of copying long invoice strings, let’s use payment method cards

Bitcoin Payment Method Cards

The article by orangesurf proposes that secure messengers like Signal render Bitcoin payment URIs as visual "Payment Method Cards" rather than disp...

Seeing a few comments asking what can be done about data embedding with unspendable UTXOs (an issue which has been around for a long time). This is a bit long, but hopefully it will be useful as a reference to the more general question of whether you can address protocol level “problems” at the miner / policy level. Realistically, short of a soft fork there is very little that can be done technically, and even that would have serious limitations & fallout (that’s the whole point of this gross protocol design). The obvious first reaction is ask miners to stop mining things like this. There are a few ways, but one would be to increase their -dustrelayfee By default it’s 0.00003 BTC/kB (3 sat/vB) resulting in a dust output limit of 330 sats for P2WSH. For this transaction with 1859 such outputs the total locked in unspendable outputs is 1859*330‎ = 613,470 sats ($736 @$120k/BTC) Lets say you successfully lobby the vast majority (95%) of miners to 10x this config value, the sender would have to choose between paying 6.1M sats ($7k) or sending as is and waiting until the small proportion of miners (5%) using the old default. They would probably do the latter because that’s enough hashrate to find 7 blocks/day on average, and what’s the rush? Having failed to stop this at the miner level you may now be tempted to lobby node runners to change their default and/or change the default in core v31. Say you were successful, and core v31 contains a higher default. The sender can just preferentially peer to try and reach miners in protocol. So you double down and you spoof preferential peering such that it’s not sufficiently reliable. The sender now has no choice but to pay a miner OOB - if they are to do this they might as well make each output be 0 sats. This could actually be mutually financially beneficial for the sender and miner, because instead of sats being burned as fees they would flow to the miner / be saved by the sender. Now to be fair it would take effort to establish these direct rails to miners who are exclusively financially motivated, but this is a fixed cost, and I have no doubt it would be done, and then integrated via API to centralized minting services. Thus, the problem would likely end up being worse than the situation we have today.

Everyone can agree that we need more decentralized block template construction. Core sees private tx broadcast as a threat to that (which is fair imo), which is part of why they are widening default policy rules. Most filter proponents are vocal ocean supporters. Ocean have already materially increased the number of entities (who are actually finding blocks) doing template construction with DATUM, currently I imagine most of these individuals are using knots, and interestingly many don’t filter out all “spam”. Knots has (iiuc) a single individual who decides what gets merged, and no doubt eventually there will be something he does / doesn’t do that will be perceived as an artificial restriction on user choice. Ultimately, the only way miners will have sufficient choice without restriction will be if they can construct their own policy (with ease) and we have already seen an example of this (Knots Lua Pull) and a more recent BIP draft to do the same in Core (see mailing list, not received well) The (perceived) threat with anything like this, is that “actual censorship” is as easy as mandating the inclusion of a filter file, and template construction is sufficiently centralized currently that IMO this is a reasonable concern. Which brings us back to the point on which we have unanimous agreement: there is a pressing need to decentralize block template production. Any action to decentralize block template production should be celebrated. Knots Lua Implementation

GitHub

Draft: Add support for Lua-based TX filtering by jasonfoura · Pull Request #119 · bitcoinknots/bitcoin

JS BIP Draft

GitHub

bips/bip-mempool-policy-scripts.md at mempool-policy-scripts · dr-bonez/bips

Bitcoin Improvement Proposals. Contribute to dr-bonez/bips development by creating an account on GitHub.

We must stop people putting data on Bitcoin, it’s a payment network Meanwhile: every lightning commitment transaction encodes a 48-bit commitment number across nLockTime & nSequence

1 sat/vB is clearing but someone just made a consolidation at 102 sat/vB 🫥

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Sense check Despite a dip in activity there are still 267k “legit” transactions per day. (Average non OP_RETURN related/Inscription over the past 90 days)

Over the past 1000 blocks, more than 30% of transactions have been below the longstanding1 sat/vB default min tx relay fee limit. If we plot the actual data, we see spikes around round feerates (1,2,3,4 sat/vB) and a (surprisingly ?) large spike in the sub 1 sat/vB fee rates on the right hand side. We can animate this graph with a 1000 block sliding window for the month of August. There is a wide range in the proportion of blocks which are < 1 sat/vB, but the 144 block rolling average has been on an uptrend in recent months (shown here is data since June, block 900000)

grid.orange.surf

> it only takes one determined spammer to make a tool to allow the less determined to spam. - @Nicolas Dorier This is the asymmetry that many filter proponents seem to miss. Most of the kind of transactions they wish to filter out are created using dedicated software (services / tools / platforms). Developers of such software can rapidly bypass any restriction using open source software like libre relay, which will get their transactions to miners. We already see this, with some platforms offering the ability to select broadcast method from a drop down, including direct broadcast to some miners.

Did you use the bitcoin core wallet in the last year?

@softsimon and I are arriving early for @BTC Prague. Get in touch if you are around from the 14th and want to meet up!

Which filter do you think core will drop / change the default for next? - Max Transaction Size - Minimum Relay Fee - Minimum Output Size

What do I do? Research: I publish chart filled data-driven reports on technical Bitcoin topics. Read at

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So many based bitcoiners at bcc8333 unconference. If you are in Barcelona check out their meetup

Meetup

Bitcoin Barcelona (BBO) | Meetup

**CAT:** Som el punt de trobada a la ciutat dedicat exclusivament a Bitcoin. Ens reunim per aprofundir en el protocol, la innovació, la cultura ci...

Block 900,000, had room to spare despite a celebratory meme inscription.

Unbelievable lack of use

41.65% of the UTXO set is dust amounts precisely at the implied default core policy dust limits for various script types. note: p2tr is the most popular 546 sat script type (68% of all 546 sat outputs). I guess degen wallets don't compute the actual dust limit?

Surprising facts from my new report on Bitcoin's UTXO set: - 49% of UTXOs are sub 1000 sats - 30% of UTXOs are inscriptions related - 100k+ 10-year-old counterparty UTXOs store arbitrary data with fake multisig pub keys Read it in full here:

mempool research

UTXO Set Report

A data driven analysis of Bitcoin's unspent transaction output (UTXO) set revealing that almost half of all UTXOs are < 1000 sats, 30% of UTXOs are...