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- Bitcoin Core removes the 80-byte OP_RETURN limit, allowing larger and multiple data outputs in transactions.
- The change aims to reduce UTXO bloat. It also seeks to streamline data handling on the network.
- The team will include the update in the next major release. However, adoption depends on whether node operators and miners support it.
Bitcoin Core developers have announced the removal of a long-standing limit on OP_RETURN transaction data, paving the way for more efficient and transparent handling of non-financial data on the Bitcoin blockchain. The update is expected to be part of the next Bitcoin Core release. It will allow transactions with OP_RETURN outputs exceeding 80 bytes and will support multiple such outputs by default.
This development was confirmed in a GitHub post on May 5 by Bitcoin developer Greg Sanders. The proposal known as PR #32359 was initiated by Bitcoin pioneer Peter Todd at the request of Chaincode Labs. The developers implemented the original 80-byte cap as a subtle nudge to discourage non-payment data storage. However, Sanders argued that the restriction has outlived its purpose and now serves more as a hindrance than a safeguard.
Sanders noted that large-data inscriptions are happening regardless and can be done in more or less abusive ways. He explained that the cap merely channels them into more opaque forms, which cause damage to the network.
Bitcoin’s OP_RETURN and Decentralized Data
OP_RETURN is a special Bitcoin script opcode that allows users to embed small pieces of arbitrary data into transactions. These outputs are provably unspendable, meaning they do not add to the unspent transaction output (UTXO) set, Bitcoin’s internal database of spendable coins. As a result, many consider them a cleaner method of storing metadata on-chain. This approach avoids bloating the system.
The feature gained renewed interest during the Ordinals and inscriptions boom of early 2024, where users began using Bitcoin to inscribe NFTs, art, and messages directly onto satoshis. However, the 80-byte cap on OP_RETURN data limited the scope of such applications, leading users to find workarounds that sometimes proved more harmful to network health.
According to Sanders, removing the OP_RETURN cap will reduce reliance on inefficient methods like fake output addresses, which contribute to UTXO bloat and increase node load. He also highlighted that some miners have already been processing larger OP_RETURN transactions, effectively rendering the cap obsolete.
Supporters cite benefits such as a more consistent transaction validation process and a cleaner, leaner UTXO set. They also emphasize improved alignment with how Bitcoin is currently used—not just as a digital currency, but as a decentralized platform supporting various data-driven use cases.
OP_RETURN Cap Removal Sparks Bitcoin Community Debate
Despite the technical rationale, the decision has stirred controversy among prominent members of the Bitcoin community. Critics argue that lawmakers introduced the change without adequate community consultation and without securing consensus.
“I think one thing is pretty clear: there is no consensus at the moment on this OP_RETURN issue,” said Marty Bent, managing partner at the Ten31 Fund.
Prominent Bitcoiner Samson Mow also voiced opposition, stating on X (formerly Twitter) that the change is “undesirable” and suggesting users could opt to remain on Bitcoin Core version 29.0 or use alternative implementations that reject the update.
Some critics have raised broader concerns, arguing that increased support for arbitrary data storage risks undermining Bitcoin’s core value proposition as a financial tool. Others have questioned whether developer affiliations with research groups and corporate sponsors are influencing protocol changes behind the scenes.
Developers reportedly considered three options: keeping the 80-byte limit, increasing the cap, or removing it entirely. After discussions within the developer community, the decision to eliminate the cap won “broad, though not perhaps unanimous, support,” according to Sanders.
Developers have scheduled the upgrade for inclusion in the next major Bitcoin Core release, but its adoption will depend on whether node operators and miners choose to run the updated software.
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