Overview
Amaru is free, open-source software that lets a computer join the Cardano network as a node, one of the many machines that check new blocks of transactions and pass them on to each other. Stake pool operators, who run the machines that keep the network going, and developers building network tools are its main audience. Amaru is designed to run on modest hardware1.
Amaru is a second, independent version of Cardano's node software, written in the Rust programming language to work side by side with the original Cardano node, which is written in another language, Haskell. Having more than one version is meant to make the network more resilient, so that it does not depend on a single codebase2. Development happens under PRAGMA, a not-for-profit open-source association launched by the Cardano Foundation, Sundae Labs, TxPipe, and other Cardano builders3. Now in beta, Amaru runs on Cardano's main network as a relay, a node that checks and forwards blocks without creating new ones, while block production is still in development4.
Key Features
- Runs on modest hardware. Amaru is built to use little memory and runs on both standard x86_64 processors and ARM-based aarch64 chips1.
- An independent second implementation. Amaru rebuilds the core parts of a Cardano node from scratch: networking, consensus (the rules nodes follow to agree on the next block), and the ledger (the record of who owns what)2.
- See what the node is doing. Amaru reports traces, logs, and metrics through OpenTelemetry, a widely used monitoring standard, so operators can watch node health with monitoring tools such as Grafana and Prometheus1.
- Checked against the original node. Amaru's developers compare its behavior with the Haskell node through conformance tests, and add deterministic simulations, which repeat the same test scenarios with identical results, and property-based testing, which runs the code against many generated inputs1.
- Reusable building blocks. Each part of Amaru, from networking to storage, also ships as a separate Rust library, so developers can reuse pieces in their own software2. Parts such as the ledger can also run on WebAssembly, a format that runs code inside web browsers1.
What to Expect
For stake pool operators and infrastructure teams, Amaru is a command-line program with no graphical interface. The project offers ready-made downloads for Linux, macOS, and Windows, plus installs through Docker, Homebrew, Nix, and Debian or RPM packages that set Amaru up as a background service5. Setup starts with a bootstrap step that loads a snapshot of the chain instead of replaying its full history. After that, the node runs, prints its progress in the terminal, and picks up where it left off after a restart6.
For developers, the source code lives on GitHub under the Apache 2.0 license5, a permissive license that allows commercial use and changes. The team records its major technical choices in public Engineering Decision Records on the Amaru website7, and holds regular public demos on Discord2.
For people curious about how Cardano pays for its infrastructure, Amaru is funded through Cardano's on-chain treasury, with community approval through governance votes8. The project's treasury page splits the budget into areas such as consensus and ledger work, each with its own owner. Spending runs through an on-chain smart contract, a program on the blockchain that enforces rules on its own, and one owner's withdrawal needs another owner's approval9.
