Bitcoin Runes is a protocol for creating fungible tokens on Bitcoin, launched in April 2024 by Casey Rodarmor (creator of Ordinals). Runes uses Bitcoin's existing UTXO model more efficiently than the earlier BRC-20 standard, making it the dominant fungible token protocol on Bitcoin.
Why Runes Exists
Before Runes, the main way to create fungible tokens on Bitcoin was BRC-20 — a standard that used Ordinal inscriptions to store token state. BRC-20 worked but had significant inefficiencies: it required multiple transactions per transfer and bloated Bitcoin's UTXO set with unnecessary data.
Runes was designed from the ground up to be UTXO-native and minimal. It leaves no "junk" UTXOs and requires fewer transactions for the same operations.
How Runes Works
OP_RETURN encoding: Rune protocol data is stored in Bitcoin's OP_RETURN output — a standard Bitcoin output that stores up to 80 bytes of arbitrary data and is provably unspendable. No new opcodes, no soft fork required.
Etching: Creating a Rune is called "etching." The etcher defines: the Rune's name (in uppercase letters, e.g., DOGGOTOTHEMOON), symbol, divisibility (decimal places), supply, and minting rules.
Minting: After etching, tokens can be minted according to the rules set at etching. Open mints allow anyone to claim tokens; premined mints allocate supply at etching.
Transferring: Rune balances are assigned to UTXOs. When you spend a UTXO holding Runes, the protocol rules define which output receives which Rune balance. Standard Bitcoin transactions carry Rune transfers automatically.
Runes vs BRC-20 vs Ordinals
| Feature | Runes | BRC-20 | Ordinals | |---------|-------|--------|---------| | Type | Fungible tokens | Fungible tokens | NFTs (non-fungible) | | Storage | OP_RETURN | Witness data | Witness data (inscriptions) | | UTXO efficiency | High | Low | Medium | | Complexity | Lower | Higher | Medium | | Ecosystem | Growing fast | Established | Established |
Runes are fungible (like ERC-20). Ordinals are non-fungible (like ERC-721). BRC-20 is the earlier fungible token attempt that Runes largely supersedes.
The Halving Launch Effect
Runes launched on block 840,000 — the Bitcoin halving block in April 2024. The first Rune etched at halving was UNCOMMON•GOODS (created by Rodarmor as an open mint). The launch drove massive Bitcoin transaction volume and fee spikes as users competed to etch and mint early Runes.
This timing was strategic: high demand for Rune minting generated substantial fees for Bitcoin miners, partially offsetting the halving reward reduction.
Bitcoin DeFi and Runes
Runes have enabled a primitive Bitcoin token ecosystem:
- Major meme tokens (RSIC•GENESIS•RUNE, DOG•GO•TO•THE•MOON) launched as Runes
- DEXes for Runes trading have emerged on Bitcoin sidechains (Stacks, Merlin) and via off-chain order books
- Runes can be wrapped and bridged to EVM chains for use in DeFi
The infrastructure for Runes DeFi is still early compared to Ethereum, but Bitcoin's TVL in DeFi is growing via Runes, Ordinals, and Bitcoin L2s (Stacks, BOB, Merlin).
Trading Runes
Major Runes marketplaces:
- Magic Eden: Supports Runes trading via Bitcoin wallet integration (Unisat, Xverse)
- OKX Web3: Built-in Runes marketplace in the OKX wallet
- Unisat: Bitcoin-native wallet and marketplace with strong Runes support
To trade Runes, you need a Bitcoin wallet that supports the Runes standard (Unisat or Xverse) and BTC for transaction fees.