Bitcoin Core Developers Plan to Remove the 80-byte Size Limit on OP_RETURN Outputs

Bitcoin Core developers plan to remove the long-standing 80-byte size limit on OP_RETURN outputs in an upcoming software release, a move that has sparked disagreement within the development community.

Bitcoin Core developers are planning to remove the size limit on OP_RETURN outputs in an upcoming software release, a move that has sparked disagreement within the development community.

OP_RETURN allows small amounts of data to be included in Bitcoin transactions with an unspendable output (UTXO). The concept has grown in popularity during the recent ordinoals and inscription boom.

According to Bitcoin Core contributor Greg Sanders, the new update would completely eliminate the current 80-byte size limit and “allow any number of these outputs." In a May 5 GitHub post, Sanders said that the restriction had outlived its purpose and lifting the cap would encourage less harmful onchain behavior.

“The cap merely channels them into more large-data inscriptions, other participants that bypass the 80-byte threshold. When the polite avenue is blocked, determined users turn to impolite ones. Some use 'bare multisig' or craft 'fake output public keys' that do enter the UTXO set, exactly the outcome OP_RETURN was invented to avoid."

Developers considered three options: keep the cap, raise it, or remove it entirely. The first two were deemed arbitrary and ineffective, while the third option garnered broad — though not unanimous — support, according to the GitHub discussion.

Sanders argued that lifting the cap would help maintain a cleaner UTXO set, reduce transaction burdens, and reaffirm simple, transparent rules within Bitcoin’s protocol.

However, not everyone agrees. Critics including JAN3 CEO Samson Mow called the removal an “undesirable change for a number of reasons.”