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Aug 24, 2019

Nimbus: ultra-light Ethereum execution layer client

License: Apache License: MIT Stability: experimental GH action-nimbus-eth1 GH action-fluffy

Discord: Nimbus Status: #nimbus-general


This repository contains development work on an execution-layer client to pair with our consensus-layer client. This client focuses on efficiency and security and strives to be as light-weight as possible in terms of resources used.

This repository is also home to fluffy, a Portal Network light client.

All consensus-layer client development is happening in parallel in the nimbus-eth2 repository.

Development Updates

Monthly development updates are shared here.

Some recent highlights include:

  • Renewed funding from the EF to accelerate development
  • Completed Berlin and London fork compatibility (EIP-1559). It now passes nearly all the EF Hive testsuite, and 100% of contract execution tests (47,951 tests)
  • New GraphQL and WebSocket APIs, complementing JSON-RPC
  • EVMC compatibility, supporting third-party optimised EVM plugins
  • Up to 100x memory saving during contract executions
  • Asynchronous EVM to execute many contracts in parallel, while they wait for data from the network
  • Proof-of-authority validation for the Goerli test network
  • Updated network protocols, to work with the latest eth/65-66 and snap/1 protocols
  • A prototype new mechanism for state sync which combines what have been called Fast sync, Snap sync and Beam sync in a self-tuning way, and allows the user to participate in the network (read accounts, run transactions etc.) while sync is still in progress
  • A significant redesign of the storage database to use less disk space and run faster.

For more detailed write-ups on the development progress, follow the Nimbus blog.

Building & Testing


  • RocksDB
  • GNU Make, Bash and the usual POSIX utilities. Git 2.9.4 or newer.

On Windows, a precompiled DLL collection download is available through the fetch-dlls Makefile target: (Windows instructions).

# MacOS with Homebrew
brew install rocksdb

# Fedora
dnf install rocksdb-devel

# Debian and Ubuntu
sudo apt-get install librocksdb-dev

# Arch (AUR)
pakku -S rocksdb

rocksdb can also be installed by following their instructions.

Obtaining the prerequisites through the Nix package manager


Users of the Nix package manager can install all prerequisites simply by running:

nix-shell default.nix

Build & Develop

POSIX-compatible OS

# The first `make` invocation will update all Git submodules.
# You'll run `make update` after each `git pull`, in the future, to keep those submodules up to date.
# Assuming you have 4 CPU cores available, you can ask Make to run 4 parallel jobs, with "-j4".

make -j4 nimbus

# See available command line options
build/nimbus --help

# Start syncing with mainnet

# Update to latest version
git pull
make -j4 update

# Run tests
make test

To run a command that might use binaries from the Status Nim fork:

./ bash # start a new interactive shell with the right env vars set
which nim
nim --version

# or without starting a new interactive shell:
./ which nim
./ nim --version

Our Wiki provides additional helpful information for debugging individual test cases and for pairing Nimbus with a locally running copy of Geth.


(Experimental support!)

Install Mingw-w64 for your architecture using the "MinGW-W64 Online Installer" (first link under the directory listing). Run it and select your architecture in the setup menu ("i686" on 32-bit, "x86_64" on 64-bit), set the threads to "win32" and the exceptions to "dwarf" on 32-bit and "seh" on 64-bit. Change the installation directory to "C:\mingw-w64" and add it to your system PATH in "My Computer"/"This PC" -> Properties -> Advanced system settings -> Environment Variables -> Path -> Edit -> New -> C:\mingw-w64\mingw64\bin (it's "C:\mingw-w64\mingw32\bin" on 32-bit)

Install Git for Windows and use a "Git Bash" shell to clone and build Nimbus.

If you don't want to compile RocksDB and SQLite separately, you can fetch pre-compiled DLLs with:

mingw32-make fetch-dlls # this will place the right DLLs for your architecture in the "build/" directory

You can now follow those instructions in the previous section by replacing make with mingw32-make (regardless of your 32-bit or 64-bit architecture):

mingw32-make nimbus # build the Nimbus binary
mingw32-make test # run the test suite
# etc.

Raspberry PI

Experimental The code can be compiled on a Raspberry PI:

  • Raspberry PI 3b+
  • 64gb SD Card (less might work too, but the default recommended 4-8GB will probably be too small)
  • Rasbian Buster Lite - Lite version is enough to get going and will save some disk space!

Assuming you're working with a freshly written image:

# Start by increasing swap size to 2gb:
sudo vi /etc/dphys-swapfile
# :wq
sudo reboot

# Install prerequisites
sudo apt-get install git libgflags-dev libsnappy-dev

mkdir status
cd status

# Install rocksdb
git clone
cd rocksdb
make shared_lib
sudo make install

# Raspberry pi doesn't include /usr/local/lib in library search path - need to add
export LD_LIBRARY_PATH=/usr/local/lib:$LD_LIBRARY_PATH

git clone

cd nimbus

# Follow instructions above!


Experimental Code can be compiled and run on Android devices

Environment setup
  • Install the Termux app from FDroid or the Google Play store
  • Install a PRoot of your choice following the instructions for your preferred distribution. Note, the Ubuntu PRoot is known to contain all Nimbus prerequisites compiled on Arm64 architecture (common architecture for Android devices). Depending on the distribution, it may require effort beyond the scope of this guide to get all prerequisites.

Assuming Ubuntu PRoot is used

# Install prerequisites
apt install librocksdb-dev

# Clone repo and build Nimbus just like above
git clone

cd nimbus


make nimbus


Experimental make variables

Apart from standard Make flags (see link in the next chapter), the following Make variables can be set to control which version of a virtual engine is compiled. The variables are listed with decreasing priority (in case of doubt, the lower prioritised variable is ignored when the higher on is available.)

    Disable legacy chunked RLPx messages which are enabled by default for synchronising against Nethermind nodes

    Enable mostly EVMC compliant wrapper around the native Nim VM

    Enable new re-factored version of the native Nim VM. This version is not optimised and coded in a way so that low memory compilers can handle it (observed on 32 bit windows 7.)

  • ENABLE_VM2=1
    Enable new re-factored version of the native Nim VM.

For these variables, using <variable>=0 is ignored and <variable>=2 has the same effect as <variable>=1 (ditto for other numbers.)

Development tips

Interesting Make variables and targets are documented in the nimbus-build-system repo.

  • you can switch the DB backend with a Nim compiler define: -d:nimbus_db_backend=... where the (case-insensitive) value is one of "rocksdb" (the default), "sqlite", "lmdb"

  • the Premix debugging tools are documented separately

  • you can control the Makefile's verbosity with the V variable (defaults to 0):

make V=1 # verbose
make V=2 test # even more verbose
make LOG_LEVEL=DEBUG nimbus # this is the default
make LOG_LEVEL=TRACE nimbus # log everything
  • pass arbitrary parameters to the Nim compiler:
make NIMFLAGS="-d:release"
  • if you want to use SSH keys with GitHub (also handles submodules):
make github-ssh
  • force a Nim compiler rebuild:
rm vendor/Nim/bin/nim
make -j8 build-nim
  • some programs in the tests subdirectory do a replay of blockchain database dumps when compiled and run locally. The dumps are found in this module which need to be cloned as nimbus-eth1-blobs parellel to the nimbus-eth1 file system root.

Git submodule workflow

Working on a dependency:

cd vendor/nim-chronicles
git checkout -b mybranch
# make some changes
git status
git commit -a
git push origin mybranch
# create a GitHub PR and wait for it to be approved and merged
git checkout master
git pull
git branch -d mybranch
# realise that the merge was done without "--no-ff"
git branch -D mybranch
# update the submodule's commit in the superproject
cd ../..
git status
git add vendor/nim-chronicles
git commit

It's important that you only update the submodule commit after it's available upstream.

You might want to do this on a new branch of the superproject, so you can make a GitHub PR for it and see the CI test results.

Don't update all Git submodules at once, just because you found the relevant Git command or make target. You risk updating submodules to other people's latest commits when they are not ready to be used in the superproject.

Adding the submodule "" to "vendor/foo":

vendor/nimbus-build-system/scripts/ status-im/foo
# or
./ add_submodule status-im/foo
# want to place it in "vendor/bar" instead?
./ add_submodule status-im/foo vendor/bar

Removing the submodule "vendor/bar":

git submodule deinit -f -- vendor/bar
git rm -f vendor/bar

Checking out older commits, either to bisect something or to reproduce an older build:

git checkout <commit hash here>
make clean
make -j8 update

Running a dependency's test suite using nim instead of nimble (which cannot be convinced not to run a dependency check, thus clashing with our jury-rigged "vendor/.nimble/pkgs"):

cd vendor/nim-rocksdb
../nimbus-build-system/scripts/ test
# or
../../ nimble test

Metric visualisation

Install Prometheus and Grafana. On Gentoo, it's emerge prometheus grafana-bin.

# build Nimbus
make nimbus
# the Prometheus daemon will create its data dir in the current dir, so give it its own directory
mkdir ../my_metrics
# copy the basic config file over there
cp -a examples/prometheus.yml ../my_metrics/
# start Prometheus in a separate terminal
cd ../my_metrics
prometheus --config.file=prometheus.yml # loads ./prometheus.yml, writes metric data to ./data
# start a fresh Nimbus sync and export metrics
rm -rf ~/.cache/nimbus/db; ./build/nimbus --prune:archive --metricsServer

Start the Grafana server. On Gentoo it's /etc/init.d/grafana start. Go to http://localhost:3000, log in with admin:admin and change the password.

Add Prometheus as a data source. The default address of http://localhost:9090 is OK, but Grafana 6.3.5 will not apply that semitransparent default you see in the form field, unless you click on it.

Create a new dashboard. Click on its default title in the upper left corner ("New Dashboard"). In the new page, click "Import dashboard" in the right column and upload "examples/Nimbus-Grafana-dashboard.json".

In the main panel, there's a hidden button used to assign metrics to the left or right Y-axis - it's the coloured line on the left of the metric name, in the graph legend.

To see a single metric, click on its name in the legend. Click it again to go back to the combined view. To edit a panel, click on its title and select "Edit".

Obligatory screenshot.


Report any errors you encounter, please, if not already documented!

  • Turn it off and on again:
make clean
make update


Licensed and distributed under either of


at your option. These files may not be copied, modified, or distributed except according to those terms.