Definition: BRC-20 is an experimental convention for representing fungible-token balances with JSON text stored in Bitcoin Ordinals inscriptions. Introduced by the pseudonymous developer Domo in 2023, it uses Bitcoin transactions to record token operations, while compatible indexers interpret those inscriptions and calculate balances. Bitcoin itself does not execute BRC-20 token contracts or maintain a native BRC-20 account ledger.
How the original BRC-20 format works
A BRC-20 inscription identifies the protocol with a field such as "p":"brc-20" and describes an operation. The original format centers on three operations:
- Deploy: records a token ticker and rules such as a maximum supply and, optionally, a limit for each mint.
- Mint: records a request to claim some of the deployed token, subject to the supply and mint rules recognized by the indexer.
- Transfer: creates a transfer inscription for an amount. To send the balance, the user then moves the UTXO carrying that inscription to the recipient. A transfer inscription is generally used once; it is not a smart-contract call that updates an account balance on Bitcoin.
These JSON records are embedded as Ordinals inscriptions on Bitcoin. Bitcoin stores and orders the transactions, but the BRC-20 rules are applied by software that reads the chain. A wallet or marketplace may show a balance only if its indexer recognizes the relevant inscriptions and applies compatible rules.
Why indexers matter
Classic BRC-20 creates a token ledger by interpreting Bitcoin data rather than by deploying a Bitcoin smart contract. Indexers identify valid deployments, mints, and transfers, then reconstruct balances from their rules and the transaction history. The inscriptions remain on Bitcoin even if a service goes offline, but a wallet’s displayed balance or a marketplace’s support can depend on its indexer and software.
If indexers apply different rules to an edge case, they can calculate different BRC-20 states from the same Bitcoin history. That makes consistent, documented rules and compatible implementations important. Domo’s original description calls BRC-20 an experiment and explicitly says it should not be treated as the definitive standard for fungible assets on Bitcoin.
Governance and later proposals
BRC-20 is not the only way to describe tokens or applications on Bitcoin. In a 2024 letter, Domo said protocol governance would move toward a maintainer model led by Best in Slot and UniSat, with input from other ecosystem participants. The Layer 1 Foundation currently identifies Best in Slot and UniSat as BRC-20 lead maintainers. That describes stewardship of the convention; it does not mean Bitcoin miners execute BRC-20 rules as part of Bitcoin consensus.
Proposals such as BRC-20 modules and the “Programmable Module” sometimes called BRC2.0 aim to add capabilities beyond the original deploy, mint, and transfer format. They are separate extensions with their own software and indexer requirements. A proposal or test implementation does not mean every BRC-20 token supports smart contracts or that an extension is live on Bitcoin mainnet; verify current status with its maintainers before using it.
Costs and practical limits
Creating and moving BRC-20 inscriptions uses Bitcoin transactions and competes for block space with other Bitcoin activity. Fees therefore change with network demand. The token’s apparent price or balance does not guarantee that a wallet, exchange, or marketplace will support deposits and withdrawals, and a ticker alone is not proof that two assets are the same token.
- It is not ERC-20: ERC-20 rules are enforced by Ethereum smart contracts; classic BRC-20 balances are reconstructed by indexers from inscriptions and Bitcoin transactions.
- It is not a Bitcoin-native account balance: Bitcoin nodes validate Bitcoin transactions, not the BRC-20 token ledger shown by a wallet.
- It does not promise cheap transactions: Inscription and transfer fees depend on Bitcoin block-space demand.
- It is experimental: The original creator cautioned users against relying on the experiment for financial decisions.
Social Media Sentiment
A discussion on the Layer 1 Foundation forum about UniSat’s modular proposal shows a technical debate rather than a simple consensus: some participants saw modules as a way to add uses while keeping basic BRC-20 balances consistent, while others questioned how indexer agreement, module approval, and governance would work. This is a historical contributor discussion from 2023, not a poll of BRC-20 users or evidence of current adoption.
Last updated: 2026-10
Related Terms
See Also
- What Happens to Bitcoin When All 21 Million Are Mined?
- NFTs and Digital Game Ownership: What Actually Changes (And What Doesn’t)
- Why Calling It a ‘Wallet’ May Have Been Crypto’s Biggest Mistake
- Swap crypto with ChangeNOW
Sources
- Domo’s original BRC-20 experiment document — Defines the experimental purpose, inscribed JSON operations, and the creator’s warning not to treat it as a definitive fungibility standard or investment basis.
- Ordinal Theory Handbook — Inscriptions — Explains how inscription content is attached to satoshis and stored in Bitcoin transactions and UTXOs.
- BRC-20 protocol reference repository — Provides protocol documentation, indexer reference material, test vectors, and payload validation resources.
- Domo’s letter on BRC-20 governance — Describes the announced transition toward a maintainer model led by Best in Slot and UniSat, with wider stakeholder input.
- Layer 1 Foundation — BRC-20 maintainers — Lists Best in Slot and UniSat as lead maintainers of the BRC-20 protocol.
- Layer 1 Foundation forum — BRC2.0 Programmable Module proposal — Describes a separate proposal for indexer-executed modules and includes a dated warning that it was not enabled on Bitcoin mainnet when posted.