- Release Candidates
- Getting Started
- Known Issues
- Future Work
Zebra is the Zcash Foundation's independent, consensus-compatible implementation of a Zcash node, currently under development. It can be used to join the Zcash peer-to-peer network, which helps keeping Zcash working by validating and broadcasting transactions, and maintaining the Zcash blockchain state in a distributed manner.
Zcash is a cryptocurrency designed to preserve the user's privacy. If you just want to send and receive Zcash then you don't need to use Zebra directly. You can download a Zcash wallet application which will handle that for you.
Please join us on Discord if you'd like to find out more or get involved!
You would want to run Zebra if you want to contribute to the Zcash network: the more nodes are run, the more reliable the network will be in terms of speed and resistance to denial of service attacks, for example.
Zebra aims to be faster, more secure, and more easily extensible than other Zcash implementations.
Every few weeks, we release a new Zebra version.
Zebra's network stack is interoperable with
and Zebra implements all the features required to reach Zcash network consensus.
Currently, Zebra validates all of the Zcash consensus rules for the NU5 network upgrade.
Zebra validates blocks and transactions, but needs extra software to generate them:
- to generate transactions, configure
zebrad's JSON-RPC port, and use a light wallet with
- to generate blocks, compile
getblocktemplate-rpcsfeature, configure the JSON-RPC port, and use a mining pool or miner with Zebra's mining JSON-RPCs. Mining support is currently incomplete, experimental, and off by default.
You can run Zebra using our Docker image. This command will run our latest release, and sync it to the tip:
docker run zfnd/zebra:1.0.0-rc.6
For more information, read our Docker documentation.
Building Zebra requires Rust, libclang, pkg-config, and a C++ compiler.
Zebra is tested with the latest
stable Rust version. Earlier versions are not
supported or tested. Note that Zebra's code currently uses features introduced
in Rust 1.65, or any later stable release.
Below are quick summaries for installing the dependencies on your machine.
General instructions for installing dependencies
Install Zebra's build dependencies:
- libclang is a library that might have different names depending on your
package manager. Typical names are
- clang or another C++ compiler:
g++(all platforms) or
- libclang is a library that might have different names depending on your package manager. Typical names are
Dependencies on Arch
sudo pacman -S rust clang pkgconf
Note that the package
libclang as well as the C++ compiler.
Once the dependencies are in place, you can build Zebra
cargo install --locked --git https://github.com/ZcashFoundation/zebra --tag v1.0.0-rc.6 zebrad
You can start Zebra by
See the Running Zebra section in the book for more details.
You can also build Zebra with the following Cargo features:
sentryfor Sentry monitoring;
filter-reloadfor dynamic tracing
flamegraphfor generating flamegraphs.
prometheusfor Prometheus metrics.
getblocktemplate-rpcsfor mining support.
You can arbitrarily combine the features by listing them as parameters of the
cargo install --features="<feature1> <feature2> ..." ...
The features are also described in the API documentation. The debugging and monitoring features are disabled in release builds to increase performance.
Configuring JSON-RPC for lightwalletd
zebrad as a
lightwalletd backend, give it this
[rpc] # listen for RPC queries on localhost listen_addr = '127.0.0.1:8232' # automatically use multiple CPU threads parallel_cpu_threads = 0
WARNING: This config allows multiple Zebra instances to share the same RPC port. See the RPC config documentation for details.
lightwalletd also requires a
It is recommended to use adityapk00/lightwalletd because that is used in testing.
lightwalletd forks have limited support, see the detailed
The recommended requirements for compiling and running
- 4 CPU cores
- 16 GB RAM
- 300 GB available disk space for building binaries and storing cached chain state
- 100 Mbps network connection, with 300 GB of uploads and downloads per month
We continuously test that our builds and tests pass on:
The latest GitHub Runners for:
- Debian Bullseye
Zebra's tests can take over an hour, depending on your machine. We're working on making them faster.
zebrad might build and run fine on smaller and slower systems - we haven't
tested its exact limits yet.
For more detailed requirements, refer to the documentation.
If Zebra's build runs out of RAM, try setting:
If Zebra's tests timeout or run out of RAM, try running:
cargo test -- --test-threads=2
(cargo uses all the processor cores on your machine by default.)
macOS Test Troubleshooting
Some of Zebra's tests deliberately cause errors that make Zebra panic. macOS records these panics as crash reports.
If you are seeing "Crash Reporter" dialogs during Zebra tests, you can disable them using this Terminal.app command:
defaults write com.apple.CrashReporter DialogType none
Network Ports and Data Usage
Zebra uses the following inbound and outbound TCP ports:
- 8233 on Mainnet
- 18233 on Testnet
Outbound connections are required to sync, inbound connections are optional. Zebra also needs access to the Zcash DNS seeders, via the OS DNS resolver (usually port 53).
Zebra needs some peers which have a round-trip latency of 2 seconds or less. If this is a problem for you, please open a ticket.
zebrad's typical mainnet network usage is:
- Initial sync: 100 GB download, we expect the initial download to grow to hundreds of gigabytes over time
- Ongoing updates: 10 MB - 10 GB upload and download per day, depending on user-created transaction size and peer requests
Zebra performs an initial sync every time its internal database version changes, so some version upgrades might require a full download of the whole chain.
For more detailed information, refer to the documentation.
Some of Zebra's tests download Zcash blocks, so they might be unreliable depending on your network connection.
You can set
ZEBRA_SKIP_NETWORK_TESTS=1 to skip the network tests.
Zebra may be unreliable on Testnet, and under less-than-perfect network conditions. See our roadmap for details.
Zebra uses around 200 GB of space for cached mainnet data, and 10 GB of space for cached testnet data. We expect disk usage to grow over time, so we recommend reserving at least 300 GB for mainnet nodes.
Zebra's database cleans up outdated data periodically, and when Zebra is shut down and restarted.
Zebra's state commits changes using RocksDB database transactions.
If you forcibly terminate Zebra, or it panics, any incomplete changes will be rolled back the next time it starts.
So Zebra's state should always be valid, unless your OS or disk hardware is corrupting data.
There are a few bugs in Zebra that we're still working on fixing:
If Zebra fails downloading the Zcash parameters, use the Zcash parameters download script instead.
Block download and verification sometimes times out during Zebra's initial sync #5709. The full sync still finishes reasonably quickly.
No Windows support #3801. We used to test with Windows Server 2019, but not any more; see the issue for details.
Experimental Tor support is disabled until Zebra upgrades to the latest
arti-client. This happened due to a Rust dependency conflict, which could only be resolved by
artiupgrading to a version of
x25519-dalekwith the dependency fix.
Orchard proofs fail to verify when Zebra is compiled with Rust 1.69 (nightly Rust). This will be resolved in the next Orchard release after 0.3.0.
--helpflag, and usage of invalid commands or options are inconsistent #5502. See the issue for details.
Performance and Reliability:
- Reliable syncing under poor network conditions
- Additional batch verification
- Performance tuning
Currently, the following features are out of scope:
- Optional Zcash network protocol messages
- Consensus rules removed before Canopy activation (Zebra checkpoints on Canopy activation)
The Zebra website contains user documentation, such as how to run or configure Zebra, set up metrics integrations, etc., as well as developer documentation, such as design documents. We also render API documentation for the external API of our crates, as well as internal documentation for private APIs.
Zebra has a responsible disclosure policy, which we encourage security researchers to follow.
Zebra is distributed under the terms of both the MIT license and the Apache License (Version 2.0).
See LICENSE-APACHE and LICENSE-MIT.