Lifting Bitcoin's OP_RETURN Cap Sparks Debate Over Its Role as a Data Carrier

Bitcoin (BTC) developers have removed the default 80-byte limit on OP_RETURN outputs in an upcoming release of Bitcoin Core, enabling the insertion of larger data payloads and multiple OP_RETURN entries within a single transaction.

The change follows a prolonged debate within the Bitcoin community over whether the existing cap, introduced in 2014, has outlived its usefulness.

As of May 12, 2025, Bitcoin Core had not merged any pull requests related to altering OP_RETURN limits and proposals remain open for review.

What Is OP_RETURN?

OP_RETURN is a script opcode that allows users to append up to 80 bytes of arbitrary information—such as text, hashes, or protocol indicators—to transactions. Unlike spendable outputs, which are stored in the unspent transaction output (UTXO) set, OP_RETURN outputs are provably unspendable, allowing nodes to prune them without loss of funds.

This capability supports nonpayment applications, including timestamping ownership proofs, embedding metadata for layer-two (L2) protocols or intentionally burning coins in targeted use cases.output