OP_RETURN

Also: nulldata, OP_RETURN output

An output whose script begins with OP_RETURN (0x6a), which makes it provably unspendable; Bitcoin Core never adds it to the UTXO set. Its bytes are non-witness, so each costs one vbyte. Consensus has never limited its size; the limits are relay policy, and Bitcoin Core 30.0 raised the default to 100,000 bytes and allowed several such outputs per transaction. The data-types reference lists Runes, alkanes protostones, small Counterparty messages, Omni Class C, Pipe and Charms among its users. BTI attributes the whole output serialization: 8 value bytes, the script length and the script.

Used by: block.space

Used on #

• Charms
• CoinSpark
• Colu
• Counterparty
• Mezcal
• OP-20
• Open Assets
• Pipe
• SPOOL
• Blockspace expansion policy
• The envelope taxonomy
• Policy observatory
• The witness discount, by protocol
• Timeline

Sources #

1. block.space docs: data types · block.space/docs/datatypes