Bitcoin Core developers have approved a change that removes the 83-byte default cap on OP_RETURN data. The update will take effect with the v30 release, expected in October.
Under the new policy, a 100,000-byte limit will replace the previous 83-byte rule. In practice, the amount of data users can include in a transaction will now be constrained by the standard transaction size (around 400 KB) or the block weight limit (4 MB).
Although nodes can still impose a lower limit using the “-datacarriersize” option, this setting is now deprecated, and there is no timeline for its removal.
Reference Implementation and Network Impact
Bitcoin Core serves as the reference implementation for the Bitcoin protocol. Its codebase is maintained by a large open-source community, and most full nodes on the network run it.
Changes to Bitcoin Core tend to have far-reaching effects, as they influence which transactions nodes will relay and validate.
Lifting the OP_RETURN limit marks a move toward a more permissive relay policy, allowing more data to flow through the network without forcing node operators to accept larger OP_RETURN fields if they choose not to.
Rising Debate Over Data-Intensive Use Cases
In recent months, discussions around data-heavy applications like Ordinals have focused on OP_RETURN, the Bitcoin opcode used to attach extra data to transactions.
Since 2014, Bitcoin Core has enforced a strict cap on how much data could be embedded this way. In May, developers signalled that the 80-byte limit would be dropped.
A recent editorial by the Core team explained that transaction acceptance rules have historically discouraged inefficient use of block space.
By removing the limit, Bitcoin Core aims to align default relay rules with actual miner behaviour, which is that miners already accept larger OP_RETURN data when it is sent directly to them.
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Many community members have voiced concerns. Some argue that allowing larger OP_RETURN fields will lead to more network congestion, driving up fees for everyday users.
One critic wrote that Bitcoin might be turned into a “generic crypto” able to serve many non-monetary purposes at the expense of volunteers who run nodes.
Proponents counter that removing the default cap will reduce incentives for users to bypass the mempool and negotiate directly with miners, a practice that could centralise transaction inclusion and harm decentralisation.
Developer Rationale and Community Input
Core developers considered three options that is to keep the existing limit, raise it, or drop it entirely. They found the first two choices arbitrary and ineffective.
Removing the cap won broad support on the project’s GitHub discussion boards, though it was not without opposition. Gloria Zhao, a Bitcoin Core developer at Chaincode Labs who merged the pull request, explained that the change fixes a mismatch between the cost of storing data and the rules governing standard transactions.
Bitcoin’s Price Actions
At press time, Bitcoin was trading at $109,588.39, up 1.67% over the past 24 hours. The global market capitalisation for Bitcoin stood at $2.17 trillion, and trading volume in the same period had risen by 27.19%.
As Bitcoin Core moves to remove its long-standing OP_RETURN limit, the network prepares for a more open data policy. Supporters believe this change brings Bitcoin closer to how miners already operate, while critics worry about possible fee increases and congestion.