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Primary protocol specifications

The foundational BRC-20 documentation exists across two authoritative sources: Domo’s original specification and the Layer1 Foundation’s updated protocol documentation.

Original BRC-20 whitepaper

  • URL: https://domo-2.gitbook.io/brc-20-experiment
  • Type: Original protocol specification
  • Source: Official/Primary (authored by @domodata, BRC-20 creator)
  • Description: The “definitive brc-20 white paper” containing the three core operations (deploy, mint, transfer), JSON inscription format specifications, balance state rules, and technical constraints including uint128 standard with max 18 decimals. Explicitly designated as unalterable.

Layer1 Foundation protocol documentation

  • URL: https://layer1.gitbook.io/layer1-foundation/protocols/brc-20/documentation
  • Type: Updated protocol documentation
  • Source: Official/Primary (Layer1 Foundation)
  • Description: Current official documentation incorporating all protocol updates: block 816,000 ord version freeze (v0.90), Jubilee upgrade (ord 0.14), and block 837,090 additions including self-mint functionality, 5-byte tickers, and burn mechanism via OP_RETURN.

Layer1 Foundation governance portal

  • URL: https://layer1.foundation/brc20
  • Type: Governance and organization portal
  • Source: Official/Primary
  • Description: Official non-profit organization page listing governance structure (President: Domo; Vice President: Isabel Foxen Duke), lead maintainers (Best in Slot, UniSat), and partner organizations. Links to official forum at https://l1f.discourse.group/.

Protocol improvement proposals

BRC2.0 technical documentation

BRC2.0 introduces EVM smart contract execution to Bitcoin’s Layer 1 without bridges or Layer 2 solutions. Gas costs are handled at the indexer level—users pay only Bitcoin transaction fees.

BRC2.0 programmable module repository

  • URL: https://github.com/bestinslot-xyz/brc20-programmable-module
  • Type: Core implementation repository
  • Source: Official/Primary (Best in Slot)
  • Description: Rust implementation using revm (Rust EVM) execution engine. Provides JSON-RPC 2.0 server supporting standard eth_* methods plus custom brc20_* methods.

Layer1 Foundation BRC2.0 proposal

  • URL: https://l1f.discourse.group/t/brc2-0-programmable-module-proposal/766
  • Type: Protocol specification/technical whitepaper
  • Source: Official/Primary (published March 31, 2025)
  • Description: Complete architectural specification detailing EVM execution engine, address translation formula, smart contract deployment via inscriptions, and custom Bitcoin precompiles at addresses 0x…ff through 0x…fb.

BRC2.0 proposals repository

  • URL: https://github.com/bestinslot-xyz/brc20-proposals
  • Type: Protocol improvement proposals
  • Source: Official/Primary
  • Description: Formal BRC improvement proposals including:
    • 000: Programmable Module specification
    • 001: 6-byte ticker namespace
    • 002: BRC20 precompile removal
    • 003: EVM upgrade to Prague
    • 004: Bitcoin transaction ID precompile

BRC2.0 explorer

Ordinals protocol documentation

BRC-20 operates as a layer built on Ordinals. Understanding the underlying ordinal theory is essential for protocol development.

Ordinal Theory Handbook

  • URL: https://docs.ordinals.com/
  • Type: Official protocol documentation
  • Source: Official/Primary (Casey Rodarmor, Raph Japh)
  • Description: Definitive guide covering ordinal numbering scheme, five notation systems (Integer, Decimal, Degree, Percentile, Name), rarity classification, inscriptions documentation, and Runes specification. Available in 14 languages.

ord GitHub repository

  • URL: https://github.com/ordinals/ord
  • Type: Reference implementation
  • Source: Official/Primary
  • Stars: 3,900+
  • Description: Index, block explorer, and command-line wallet. Current release v0.24.2 (November 2025).

Ordinals BIP (draft)

  • URL: https://github.com/ordinals/ord/blob/master/bip.mediawiki
  • Type: Technical specification
  • Source: Official/Primary (Casey Rodarmor)
  • Description: 15-line algorithm specification for ordinal assignment, Python pseudocode for subsidy calculation, satpoint notation, and compatibility analysis for covenants and Lightning Network.

Casey Rodarmor’s technical writings

GitHub repositories and implementations

Best in Slot Open Protocol Indexer (OPI)

  • URL: https://github.com/bestinslot-xyz/OPI
  • Type: Reference indexer implementation
  • Source: Official/Primary (Lead Maintainer)
  • Stars: 220+
  • Description: Open-source indexing client using fork of ord 0.23.2. Modules for BRC-20, Bitmap, SNS, and Runes. PostgreSQL backend with reorg protection and block hash verification.

BRC-20 indexer rules documentation

  • URL: https://docs.bestinslot.xyz/brc-20-indexer-rules
  • Type: Implementation specification
  • Source: Official/Primary
  • Description: Critical indexer rules: MIME type must be “text/plain” or “application/json”; ALL JSON fields must be strings (not numbers); use byte count for UTF-8 emoji tickers; reorg handling requirements.

Additional repositories

RepositoryURLType
BRC-20 Devs Orghttps://github.com/brc20-devsDevelopment organization
UniSat BRC-20 Indexerhttps://github.com/unisat-wallet/libbrc20-indexerGo indexer library
OKX BRC20 Indexerhttps://github.com/okx/ordProtocol implementation
Next-DAO Indexerhttps://github.com/Next-DAO/brc20_indexerNode.js indexer

Indexer API documentation

Four major indexers provide developer APIs for BRC-20 data access.

Best in Slot API

UniSat API

OKX API

Hiro Ordinals API

Wallet SDK and integration documentation

Sats Connect (Xverse)

  • URL: https://docs.xverse.app/sats-connect
  • npm: sats-connect (~2M downloads)
  • Type: Official SDK
  • Languages: JavaScript/TypeScript
  • Description: Primary library for Bitcoin wallet connections. Supports wallet_connect, signPsbt, ord_getInscriptions, createInscription. Compatible with Xverse, Leather, and other Bitcoin wallets.

UniSat wallet integration

Leather/Hiro Connect

Core Bitcoin libraries

LibraryURLPurpose
bitcoinjs-libhttps://github.com/bitcoinjs/bitcoinjs-libCore Bitcoin transactions, PSBT (BIP-174), Taproot
micro-ordinalshttps://github.com/paulmillr/micro-ordinalsMinimal inscriptions library
@scure/btc-signerhttps://www.npmjs.com/package/@scure/btc-signerAudited PSBT/Taproot signing
msignerhttps://github.com/me-foundation/msignerPSBT signer for Ordinals marketplaces

Relevant Bitcoin Improvement Proposals

BRC-20 and Ordinals depend on Taproot (activated block 709,632, November 2021) and PSBT for marketplace transactions.

Taproot BIPs (foundation for inscriptions)

BIPTitleURLRelevance
BIP-340Schnorr Signatureshttps://github.com/bitcoin/bips/blob/master/bip-0340.mediawiki64-byte signatures, batch verification
BIP-341Taproothttps://github.com/bitcoin/bips/blob/master/bip-0341.mediawiki4MB witness limit enables inscriptions
BIP-342Tapscripthttps://github.com/bitcoin/bips/blob/master/bip-0342.mediawikiScript execution for Taproot

PSBT BIPs (marketplace transactions)

BIPTitleURLRelevance
BIP-174PSBT Formathttps://github.com/bitcoin/bips/blob/master/bip-0174.mediawikiCore format for BRC-20 atomic swaps
BIP-370PSBT Version 2https://github.com/bitcoin/bips/blob/master/bip-0370.mediawikiEnhanced transaction construction
BIP-371Taproot PSBT Fieldshttps://github.com/bitcoin/bips/blob/master/bip-0371.mediawikiRequired for inscription transactions

Technical comparisons to other Bitcoin token standards

ProtocolData StorageState ValidationLightningSmart Contracts
BRC-20Witness (4MB)Off-chain indexersLimitedNone
BRC2.0Witness + OP_RETURNOff-chain indexers + EVMLimitedYes (full EVM)
RunesOP_RETURN (<80 bytes)UTXO-nativeNativeNone
RGBCommitments onlyClient-sideNativeYes (AluVM)
Taproot AssetsMerkle rootsUniverse serversNativeLimited
Key architectural difference: BRC-20 stores all data on-chain but token balances depend entirely on correct indexer interpretation, introducing centralization risks absent in UTXO-native protocols like Runes. Casey Rodarmor designed Runes specifically to reduce UTXO proliferation caused by BRC-20.

Security analysis resources

CertiK risk analysis

Cyberscope audit services