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General Documentation

API Guide


Go 1.19

GMP and OpenSSL

On macOS:

brew install gmp
brew install openssl
sudo ln -sf /usr/local/opt/openssl@1.1 /usr/local/opt/openssl

On Linux (Ubuntu)

sudo apt install libgmp-dev  libssl-dev  make gcc g++

On Linux (Cent OS / Amazon Linux 2)

sudo yum install glibc-static gmp-devel gmp-static openssl-libs openssl-static gcc-c++

Docker (for testing)

On macOS:

brew install --cask docker
open /Applications/

On Linux, reference official documentation here.

Bash 4+

For macOS, you can reference this guide. For Linux, you can reference this guide.

Dev Environment

Most repos from harmony-one assumes the GOPATH convention. More information here.

First Install

Clone and set up all of the repos with the following set of commands:

  1. Create the appropriate directories:
mkdir -p $(go env GOPATH)/src/
cd $(go env GOPATH)/src/

If you get 'unknown command' or something along those lines, make sure to install golang first.

  1. Clone this repo & dependent repos.
git clone
git clone
git clone
cd harmony
  1. Build the harmony binary & dependent libs
go mod tidy

Run bash scripts/ to ensure build tools are of correct versions. If you get 'missing go.sum entry for module providing package <package_name>', run go mod tidy.

Dev Docker Image

Included in this repo is a Dockerfile that has a full harmony development environment and comes with emacs, vim, ag, tig and other creature comforts. Most importantly, it already has the go environment with our C/C++ based library dependencies (libbls and mcl) set up correctly for you.

You can build the docker image for yourself with the following commands:

cd $(go env GOPATH)/src/
make clean
docker build -t harmony .

If your build machine has an ARM-based chip, like Apple silicon (M1), the image is built for linux/arm64 by default. To build for x86_64, apply the --platform arg like so:

docker build --platform linux/amd64 -t harmony .

Learn more about the --platform arg and multi-CPU architecture support, here and here.

Then you can start your docker container with the following command:

docker run --rm --name harmony -it -v "$(go env GOPATH)/src/" harmony /bin/bash

Note that the harmony repo will be shared between your docker container and your host machine. However, everything else in the docker container will be ephemeral.

If you need to open another shell, just do:

docker exec -it harmony /bin/bash

Learn more about docker here.


The make command should automatically build the Harmony binary & all dependent libs.

However, if you wish to bypass the Makefile, first export the build flags:

export CGO_CFLAGS="-I$GOPATH/src/ -I$GOPATH/src/ -I/opt/homebrew/opt/openssl@1.1/include"
export CGO_LDFLAGS="-L$GOPATH/src/ -L/opt/homebrew/opt/openssl@1.1/lib"
export GO111MODULE=on

Then you can build all executables with the following command:

bash ./scripts/ -S

Reference bash ./scripts/ -h for more build options


One can start a local network (a.k.a localnet) with your current code using the following command:

make debug

This localnet has 2 shards, with 11 nodes on shard 0 (+1 explorer node) and 10 nodes on shard 0 (+1 explorer node).

The shard 0 endpoint will be on the explorer at http://localhost:9599. The shard 1 endpoint will be on the explorer at http://localhost:9598.

You can view the localnet configuration at /test/configs/local-resharding.txt. The fields for the config are (space-delimited & in order) ip, port, mode, bls_pub_key, and shard (optional).

One can force kill the local network with the following command:

make debug-kill

You can view all make commands with make help


To keep things consistent, we have a docker image to run all tests. These are the same tests ran on the pull request checks.

Note that all test Docker containers bind several ports to the host machine for your convenience. The ports are:

  • 9500 - Shard 0 RPC for a validator
  • 9501 - Shard 1 RPC for a validator
  • 9599 - Shard 0 RPC for an explorer
  • 9598 - Shard 1 RPC for an explorer
  • 9799 - Shard 0 Rosetta (for an explorer)
  • 9798 - Shard 1 Rosetta (for an explorer)
  • 9899 - Shard 0 WS for an explorer
  • 9898 - Shard 1 WS for an explorer

This allows you to use curl, hmy CLI, postman, rosetta-cli, etc... on your host machine to play with or probe the localnet that was used for the test.

Go tests

To run this test, do:

make test-go

This test runs the go tests along with go lint, go fmt, go imports, go mod, and go generate checks.

RPC tests

To run this test, do:

make test-rpc

This test starts a localnet (within the Docker container), ensures it reaches a consensus, and runs a series of tests to ensure correct RPC behavior. This test also acts as a preliminary integration test (more thorough tests are done on the testnets).

The tests ran by this command can be found here.

If you wish to debug further with the localnet after the tests are done, open a new shell and run:

make test-rpc-attach

This will open a shell in the docker container that is running the Node API tests.

Note that the docker container has the Harmony CLI on path, therefore you can use that to debug if needed. For example, one could do hmy blockchain latest-headers to check the current block height of localnet. Reference the documentation for the CLI here for more details & commands.

Rosetta tests

To run this test, do:

make test-rosetta

This test starts a localnet (within the Docker container), ensures it reaches a consensus, and runs the Construction & Data API checks using the rosetta-cli. This test also acts as a preliminary integration test (more thorough tests are done on the testnets).

The config for this test can be found here & here

Similar to the RPC tests, if you wish to debug further with the localnet after the tests are done, open a new shell and run:

make test-rosetta-attach


Harmony is licensed under GNU Lesser General Public License v3.0. See LICENSE file for the terms and conditions.

Harmony includes third-party open-source code. In general, a source subtree with a LICENSE or COPYRIGHT file is from a third party, and our modifications thereto are licensed under the same third-party open source license.

Also please see our Fiduciary License Agreement if you are contributing to the project. By your submission of your contribution to us, you and we mutually agree to the terms and conditions of the agreement.

Contributing To Harmony

See CONTRIBUTING for details.

Development Status

Finished Features

  • Fully sharded network with beacon chain and shard chains
  • Sharded P2P network and P2P gossiping
  • FBFT (Fast Byzantine Fault Tolerance) Consensus with BLS multi-signature
  • Consensus view-change protocol
  • Account model and support for Solidity
  • Cross-shard transaction
  • VRF (Verifiable Random Function) and VDF (Verifiable Delay Function)
  • Cross-links
  • EPoS staking mechanism
  • Kademlia routing

Planned Features

  • Resharding
  • Integration with WASM
  • Fast state synchronization
  • Auditable privacy asset using ZK proof