Runes Protocol

💡 The Plain-English Definition

Runes is a fungible-token protocol on Bitcoin — a way to create and transfer custom tokens (interchangeable units, like coins of one kind) directly on the Bitcoin blockchain, using Bitcoin’s own UTXO model. It launched at the April 2024 halving and is designed to be more efficient and more Bitcoin-compatible than earlier token standards.

🤔 But Why Though?

Before Runes, the dominant fungible-token standard on Bitcoin was BRC-20, which worked by inscribing JSON data (a text format) into Bitcoin’s witness section using the Ordinals protocol. BRC-20 was popular but technically messy: it created enormous numbers of tiny junk UTXOs — Unspent Transaction Outputs, the discrete chunks of bitcoin that every full node has to store — which bloated the UTXO set and made running a node more expensive for everyone.

Casey Rodarmor, who created Ordinals, designed Runes as a “harm reduction” alternative. His reasoning: if people are going to create tokens on Bitcoin regardless, they should at least do it in a way that doesn’t burden the network with garbage. Runes stores its token data in OP_RETURN outputs — a Bitcoin script feature that marks an output as unspendable so nodes can drop it from the UTXO set. Token balances are tracked in ordinary UTXOs, using Bitcoin’s own accounting rather than a separate indexer, which makes Runes fit Bitcoin’s existing infrastructure far better.

Here’s roughly how it works. Creating a new Rune is called “etching” — you define its name (1–26 uppercase letters, A–Z only), how divisible it is, and its minting terms. All of that is encoded in a Runestone, a small data structure inside the transaction’s OP_RETURN output. Minting then produces tokens according to those terms, and transfers use “edicts” — instructions in the Runestone that direct how Runes move across a transaction’s outputs. There’s a neat safety feature called the cenotaph: if a Runestone is malformed, all the input Runes are simply burned (destroyed) rather than creating an invalid state, so errors fail cleanly.

Rodarmor is candid about the space, describing it as roughly “99.9% scams and memes” — he built the protocol as harm reduction while staying personally sceptical of most token use cases. Even so, as of early 2026 Runes fee revenue has settled at around 15% of total miner income during active periods, a meaningful contribution to Bitcoin’s long-term security budget.

🌍 The Real-World Analogy

Think of Runes like a more efficient system of cloakroom tickets at a venue. The old system (BRC-20) needed a separate physical stub for every token — stubs piling up everywhere, clogging the works. Runes uses the venue’s existing numbered coat hooks (the UTXOs) to track ownership, with a small printed slip (the OP_RETURN output) recording what’s assigned where. Same result — tokens tracked and transferable — but using existing infrastructure instead of creating new clutter.