Flexible BFT Consensus Engine in Rust
State-of-the-art implementation of Tendermint

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About

Malachite is a Byzantine-fault tolerant (BFT) consensus engine implemented in Rust.

The Malachite team from Informal Systems has officially joined Circle, bringing their expertise and IP to help build Arc, an open Layer-1 blockchain purpose-built for stablecoin finance. Visit arcnetwork.xyz for more information.

Malachite /ˈmæl.ə.kaɪt/ is pronounced as follows: "Mala" (like in Malaysia) + "kite" (like the flying toy).

Important

Malachite is alpha software and under heavy development. The software is provided "as is" and has not been externally audited; use at your own risk.

Goals

Malachite aims to empower developers building decentralized systems—including sequencers, social networks, and Layer-1 blockchains—by offering a flexible, reliable, and high-performance BFT consensus engine. It now serves as the consensus foundation for Arc, a new purpose-built blockchain developed by Circle.

Features

Tendermint as a Library

Bundled with Malachite comes a state-of-the-art implementation of the Tendermint BFT consensus algorithm. Tendermint is an optimistically responsive consensus algorithm, and therefore exhibits high-performance, and has found adoption in many decentralized systems through its implementation in Go as part of CometBFT.

Design

Key design decisions in Malachite are heavily inspired by lessons and experiences of maintaining CometBFT throughout the years. Malachite addresses numerous points of technical debt in the design of consensus engines, resulting in a lean, flexible, and reliable solution that performs at the highest level.

Reliability and Performance

Parts of Malachite were co-designed with their formal specification and model checking, notably for the Tendermint algorithm, which improved the confidence and reliability of this core library.

Early experiments with Malachite show an average finalization latency of 780 ms at a scale of 100 validators with 1MB blocks. Depending on the setup, Malachite can clear up to 2.5 blocks per second or finalize up to 13.5 MB/s (around 50,000 transactions per second).

Future performance benchmarks will be maintained and published as part of Arc’s open-source documentation at a future date.

Overview

Repository

The repository is split into three areas, each covering one of the important aspects of this project:

1. code: Contains the Rust implementation of the Tendermint consensus algorithm, split across multiple Rust crates.
2. docs: Contains Architectural Decision Records (ADRs) and other documentation, such as the 2018 paper describing the core consensus algorithm.
3. specs: Contains English and Quint specifications.

Crates and Status

Note

The actual name of each crate is prefixed with informalsystems-malachitebft-. For instance, the crate denoted by core-consensus below can be found on crates.io as informalsystems-malachitebft-core-consensus.

Core consensus algorithm

Crate name	Crate	Docs
core-consensus
core-driver
core-state-machine
core-types
core-votekeeper

Consensus engine

Crate name	Crate	Docs
app-channel
app
codec
config
discovery
engine
metrics
network
peer
proto
sync
wal

Building with Malachite

As a guiding point to understand how to use Malachite, please read ARCHITECTURE.md.

You can also check out the examples for a more in-depth experience.

Contributing

If you would like to contribute to the Malachite open-source codebase, please see CONTRIBUTING.md. We invite all contributors.

Requirements

• Rust v1.82+ (rustup.rs)
• Quint v0.22+ (github.com)

Acknowledgements

Malachite would not have been possible without the kind support of the Starknet ecosystem. We are grateful to StarkWare Industries for prompting the initial discussions of building Tendermint in Rust, to Starknet Foundation for funding and fostering a collaborative environment, and to both of these organizations plus numerous others in the ecosystem for their constructive feedback on earlier designs of Malachite.

We are also thankful for the collaboration with Farcaster. This led to further refinements and maturing of the Malachite codebase, and their approach to building complex systems and shipping valuable products is an inspiration for us.

These collaborations reflect work completed prior to the Malachite team joining Circle.

License

Copyright © 2025 Circle Internet Group, Inc. All rights reserved.

Licensed under the Apache License, Version 2.0 (the "License"); you may not use the files in this repository except in compliance with the License. You may obtain a copy of the License at

https://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.