What is
RGB Protocol on Bitcoin?
RGB Protocol on Bitcoin is the client-side validation layer for issuing digital assets on Bitcoin — natively integrated with the Lightning Network. This page explains what it is, why it was built, and how it works, from first principles.
RGB Protocol on Bitcoin lets you issue and transfer any digital asset on Bitcoin — keeping all contract data private, off-chain, and transferable at Lightning speed.
RGB Protocol on Bitcoin,
defined.
◎ Technical definitions on this page are based on official RGB documentation at docs.rgb.info ↗
Official definition — docs.rgb.info
RGB is a protocol for issuing and transferring digital assets and rights on Bitcoin through customizable off-chain contracts, using client-side validation to keep transaction data off-chain while relying on the Bitcoin blockchain as a commitment layer to prevent double spending. This approach ensures greater scalability, enhanced privacy, and flexibility.
In plain language: RGB lets you create and move any kind of digital asset — a token, a stablecoin, an NFT, a digital identity, a DAO right — directly on Bitcoin, without creating a new blockchain, without validators, and without publishing anything sensitive on-chain.
The key insight is that most of the data in a digital asset transaction doesn’t need to be public. The only thing that needs to be on the Bitcoin blockchain is a small cryptographic proof that says “a valid transaction happened here.” Everything else — who owns what, how much, under what conditions — stays private between the parties involved.
Analogy
Think of a signed check. The check is valid because you signed it and the other party holds it — not because the bank published the full transaction details in a public newspaper. RGB works the same way: contracts are valid because the parties hold the data and can prove its history, not because everyone on the network stores a copy.
Why existing approaches
don’t work on Bitcoin.
Bitcoin was designed to be a permissionless, censorship-resistant monetary network. It was not designed to store arbitrary contract data on-chain — and for good reason. On-chain storage creates three fundamental problems.
Every node stores everything
– All contract data is public by default
– Every node re-executes every contract
– Scalability limited by block size
– Privacy impossible by design
– Requires a separate blockchain
Each party validates only their own data
– Contract data stays private between parties
– Each user validates only their own history
– Unlimited horizontal scalability
– Privacy by design, not by exception
– Runs natively on Bitcoin
As documented in docs.rgb.info, the core insight behind RGB is that the logic of validation can be reversed: instead of every node validating everything, each participant validates only their own relevant slice of history — while Bitcoin stores only a compact cryptographic commitment that prevents double-spending.
Three ideas that make
RGB possible.
RGB Protocol on Bitcoin is built on three cryptographic building blocks that work together. You don’t need to understand the details to use RGB — but knowing the concepts helps.
Client-side validation
Each user validates only the history of state transitions that are relevant to their own assets — from the contract’s first creation (genesis) to the asset they currently hold. This private “shard” of history is exchanged directly between sender and receiver at transfer time. Nothing is broadcast to the network except a tiny cryptographic commitment.
Single-use seals
Every RGB operation is bound to a Bitcoin UTXO — an unspent transaction output. Spending that UTXO “closes the seal” and makes the associated state transition final and tamper-proof. Just like a Bitcoin UTXO can only be spent once, an RGB seal can only be closed once. This is what prevents double-spending of RGB assets
Schema-based contracts
RGB contracts are defined by a Schema — a formal template that specifies the contract’s state structure and the rules governing how that state can change. Schemas are composable: you can build fungible tokens, NFTs, identity systems, or any custom contract type using the same underlying system.
How it fits together
The Schema defines what the contract is. Client-side validation ensures only the relevant parties see the data. Single-use seals ensure the transition is final and unique. Bitcoin provides the timestamp and the anti-double-spend guarantee.
RGB is a layer on top of
Bitcoin and Lightning.
As described in the official RGB documentation, RGB is part of the broader ecosystem of Bitcoin distributed computing — a layer that sits above Bitcoin’s base layer and, optionally, above the Lightning Network.
Assets, contracts, and digital rights
Fungible tokens, NFTs, stablecoins, identity systems, DAO rights. All contract data off-chain, validated by client-side validation, anchored to Bitcoin or Lightning.
Instant settlement, near-zero fees
RGB assets flow through typed Lightning channels natively. The RGB state transition is embedded in the Lightning commitment transaction — the same channel, the same security, RGB assets moving at Lightning speed.
More than tokens —
any digital right on Bitcoin.
Because the Schema system supports arbitrary state structures, RGB is not limited to simple token transfers. Here are the most common use cases, all running on Bitcoin mainnet as of v0.11.1.
Fungible tokens
Issue fixed or inflatable supply tokens. Ticker, name, precision, and supply defined at genesis. Transferable on-chain or over Lightning.
Stablecoins on Lightning
Issue stablecoins that transfer natively over the Lightning Network — instant, private, no bridge, no custodian. Tether has announced USDt on RGB.
NFTs and collectibles
Unique digital assets with embedded media or external attachments. Ownership history stays fully private between parties.
Decentralized identity
Bind verifiable credentials to Bitcoin UTXOs. Self-sovereign identity with no registry, no custodian, no on-chain trace of personal data.
Real-world assets
Tokenize real estate, commodities, and financial instruments. Settled on Bitcoin, enforced by cryptography and contract logic.
Proof of publication
Record the existence of documents or agreements at a specific point in time — Bitcoin-level immutability, no third-party notary required.
From concept to
Bitcoin mainnet.
Single-use seals proposed
Peter Todd proposes single-use seals — the cryptographic primitive that makes client-side validation tamper-proof on Bitcoin.
RGB concept originated
Giacomo Zucco and Peter Todd conceptualize RGB as a protocol for client-side validated assets on Bitcoin, building on single-use seals.
Protocol development
Active development of the RGB protocol specification, client-side validation libraries, and the Schema system. Multiple testnet releases validate the architecture. Active development continues at github.com/rgb-protocol.
RGB v0.11.1 launches on Bitcoin mainnet
The most significant protocol release to date goes live on mainnet — enabling production-grade issuance and transfer of digital assets on Bitcoin and Lightning.
Ready to learn
more?
Full protocol documentation
Complete technical specification from the RGB Protocol team.
RGB & Lightning Network
How RGB assets move through Lightning channels natively.
Client-side validation
The cryptographic model behind RGB — explained step by step.
Build on RGB — GitHub
Active development repositories, SDK, and protocol source code.
Wallets & ecosystem
Start using RGB Protocol on Bitcoin today with compatible wallets.
RGB Protocol on Bitcoin AI Assistant
Ask questions about client-side validation and RGB.
Ready to go further
with RGB Protocol on Bitcoin?
Choose your path — learn the protocol, use it, or build on it.