The Universal Protocol

The best protocol is the one we build together — block by block.

What is Universal Protocol?

An evolution of BRC-20, built on a prunable, efficient, and Satoshi-faithful OP_RETURN foundation for Bitcoin's long-term health.

Introduction

BRC-20's radical simplicity sparked a revolution. The Universal Protocol honors that spirit by resolving its foundational flaws. We migrate logic from witness data to prunable OP_RETURN outputs—a deliberate choice for Bitcoin's long-term health and decentralization.

This is not a replacement, but a profound extension. It maintains backward compatibility while establishing the most robust accountability system for a token protocol on Bitcoin.

Satoshi-Faithful Design

The Universal Protocol uses prunable OP_RETURN outputs, ensuring efficient blockchain storage while maintaining Bitcoin's core principles of decentralization and long-term sustainability.

Fundamental Concepts

Understanding the Universal Protocol requires familiarity with four core concepts that define how transactions are structured and processed.

Inputs (UTXOs)

Standard Bitcoin UTXOs authorize the transaction and provide network fees. These inputs follow Bitcoin's standard UTXO model.

OP_RETURN Output

The core of the protocol. A compact JSON payload (≤ 80 bytes) defines the operation. This is where the magic happens.

{
  "p": "brc-20",
  "op": "transfer",
  "tick": "OPQT",
  "amt": "100"
}

Recipient Output

The first valid output after an OP_RETURN receives the tokens. Explicit and clear—no ambiguity about where tokens are going.

Account-Based Model

Balances are tied to addresses, not fragile UTXOs. Your tokens are safe from accidental burns—you can't accidentally destroy tokens by spending the wrong UTXO.

Operation Specifications

The Universal Protocol supports three core operations: Deploy, Mint, and Transfer. Each operation has a specific structure and purpose.

Deploy Operation

Registers a new BRC-20 token and its properties. This must be the first output in the transaction.

JSON Payload

{
  "p": "brc-20",
  "op": "deploy",
  "tick": "OPQT",
  "max": "21000000",
  "lim": "1000"
}

Transaction Structure

Component	Description
Input(s)	Standard UTXO(s) for fees
Output 0 (OP_RETURN)	The deploy JSON payload
Output 1 (Dummy)	Structurally required recipient, often the sender's change address

Atomic Multi-Operation Transactions

A core feature of the Universal Protocol is batching multiple operations into a single, atomic Bitcoin transaction. This leads to massive fee savings and enables powerful, trust-minimized functionalities.

Powerful Primitives

This atomicity is the key to building DeFi on Bitcoin's base layer without complex L2s.

Multi-Transfer

Send different tokens to multiple people in one go. Alice gets OPQT, Bob gets ORDI.

→ OP_RETURN: transfer OPQT to Alice

→ Recipient: Alice's Address

→ OP_RETURN: transfer ORDI to Bob

→ Recipient: Bob's Address

→ Change Output

Atomic Deploy & Full-Supply Mint

Launch a new token and secure the entire supply in a treasury address instantly. 100% front-run-proof.

→ OP_RETURN: deploy 'NEW' token

→ OP_RETURN: mint entire supply of 'NEW'

→ Recipient: Treasury Address

→ Change Output

Two-Party Atomic Swap (PSBT)

Alice and Bob trustlessly trade tokens. The transaction is only valid with both their signatures.

→ OP_RETURN: Alice sends OPQT

→ Recipient: Bob's Address

→ OP_RETURN: Bob sends ORDI

→ Recipient: Alice's Address

Operation Proposal Improvements (OPIs)

The protocol evolves through a transparent, community-driven governance process inspired by Bitcoin's BIPs. OPIs provide a formal framework for adding new features.

OPI-000: no_return

A standardized one-way bridge to migrate tokens from the Ordinals inscription standard. Burn an Ordinal transfer inscription to Satoshi's Genesis address, and the Simplicity Indexer credits the equivalent amount to your Universal balance.

Input #0: UTXO with Ordinal inscription

Output #0: OP_RETURN with 'no_return'

Output #1: Burn to Genesis Address

Suggest an OPI

Have an idea for a new Universal Protocol operation or improvement? Propose it to the community via the official GitHub organization.

Propose on GitHub →

Comparative Analysis

Understanding how the Universal Protocol differs from the Ordinals inscription standard helps clarify its advantages.

Criterion	Universal Protocol (OP_RETURN)	Ordinals Inscription Standard
Data Location	Compact JSON in OP_RETURN outputs	Data inscribed in SegWit witness
On-chain Footprint	Prunable; extremely efficient	Larger due to witness data
Transaction Cost	Significantly lower, especially for batch ops	Higher
Multi-Recipient	Native support via sequenced outputs	Complex; requires separate transfers
Logic	Explicit: operation & destination linked	Implicit: logic tied to the satoshi

Security & Best Practices

Security Considerations

Critical Output Ordering

The destination of a transfer depends ENTIRELY on correct output ordering. Wallets and users must rigorously validate this before signing.

Indexer Reliance: System integrity relies on correct and consistent Simplicity-compliant indexers.

Irreversible Operations: All confirmed operations are final. Double-check addresses and amounts.

Best Practices

Protection Against Burns: You CANNOT accidentally destroy tokens. Balances are tied to addresses, not UTXOs. A specific transfer is always required.
Leverage Batching: Use multi-operation transactions for airdrops or exchange withdrawals to save massively on fees.
Validate Before Signing: Always use a tool to decode and inspect the raw transaction before signing to verify payloads and ordering.

The Simplicity Indexer

The production-ready reference implementation of the Universal protocol. Designed for developers, exchanges, and infrastructure providers who demand robust, verifiable state.

Production-Ready Implementation

The Simplicity Indexer is the official reference implementation, providing robust indexing and state management for the Universal Protocol.

View on GitHub →