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instagibbs / op_return.md
Last active September 24, 2025 13:10

Caveat Emptor

I (instagibbs) was asked to draft a statement, I feel this is a fair summation of the project's direction. I might be wrong

Retiring the 80-Byte OP_RETURN Limit

Bitcoin Core’s next release will, by default, relay and mine transactions whose OP_RETURN outputs exceed 80 bytes and allow any number of these outputs. The long-standing cap, originally a gentle signal that block space should be used sparingly for non-payment proof of publication data, has outlived its utility.

Ecash mints funded with Spillman channels: The ultimate nodeless Lightning wallet

Overview

This proposal introduces a self-custodial credit system that sits in front of an existing ecash mint. The users balance is held in a trustless credit contract that can be instantly swapped for ecash tokens offchain at the time of payment. Custodial risk only exists while payments are in flight, which is usually seconds, and only for the amount currently being transacted. The balance is always self-custodial and if the mint disappears or is uncooperative the user can unilaterally exit and reclaim their credits onchain.

The protocol works on Bitcoin today and does not require a soft fork or any new opcodes. Infact it doesn't require any opcodes at all. The protocol is almost entirely off chain, every possible way to execute the trustless credit contract results in a MuSig2 taproot key path spend onchain, no Bitcoin Script required.

The problem