These instructions work for Ubuntu (> v18.04) and Debian (> v10 buster). There may be some variations for other distros.

From a wheel Using pip3

Install some dependencies (you will need > python3.6) :-

#> sudo apt install python3 python3-pip
#> sudo pip3 install web3fsnpy  (or pip3 install web3fsnpy --user if you want to install a username only copy)

Quick Start

You can find some example python programs at Code Examples designed to demonstrate the API’s functionality. These will be added to as new functions are developed.

You will probably need to set the environmental variable FSN_PRIVATE_KEY to be able to use any write transaction methods. Get your private key from your Fusion wallet (click on ‘View details’) and then :-


Alternatively you can generate your private key using your wallet JSON file and an input password. The way to do this is illustrated in Code Examples

To update (frequent updates available) just type :-

#> sudo pip3 install --upgrade web3fsnpy  (or pip3 install --upgrade web3fsnpy --user)

Now you need to update the PYTHONPATH environmental variable to your .bashrc file assuming that you are in the folder web3fsnpy :-

#> echo "export PYTHONPATH=$PWD:$PWD/web3fsnpy:$PYTHONPATH">>~/.bashrc

Now restart your shell to activate the PYTHONPATH.

Note that you may be able to substitute the command pip for pip3 and python for python3, depending on how your system is set up. We assume from now on that pip and python have the version 3.x

Developer setup

For a developer setup, although it is not required, you will likely need to install Ethereum’s according to the instructions at

To install web3fsnpy :-

#> git clone

The dependencies are listed in the file requirements.txt

It is best practice to operate within a virtualenv when modifying code, so as to isolate dependency issues. The –no-site-packages option below prevents usage of any other python modules that may exist on your system, but which might cause an inconsistency with web3fsnpy :-

#> virtualenv --no-site-packages -p /usr/bin/python3 env   # assuming that python3 is there - check with 'which python3'
#> source env/bin/activate              # this changes the prompt and puts you into your virtualenv

You should check that you are now using local versions of python and pip :-

#> which python     # should output an answer within your env/bin/python folder
#> which pip        # same
#> python --version # should indicate a 3.x version
#> pip --version    # same

To install the python dependencies in this virtual environment from the file requirements.txt :-

#> pip install -r requirements.txt

Check that the scope includes the correct python module versions :-

#> pip list  (or pip show <module name> )

Sometimes a pre-existing install may have a higher version number of a module, which can cause unpredictable results.

Connection to the Blockchain

There are three ways to connect to the blockchain:- HTTP, WebSocket and IPC. If you are not running a node on your machine, then WebSocket is preferred over HTTP, since it allows asynchronous bi-directional communication.

There are two ‘networks’ :- ‘mainnet’ and ‘testnet’.

The ‘default’ ‘gateway’ values hardcoded into the Fsn class constructor __init__(linkToChain) method are as follows:-

WebSocket (testnet):- ‘wss://’
WebSocket (mainnet):- ‘wss://’
HTTP (testnet):- ‘
HTTP (mainnet):- ‘
IPC :- ‘/home/root/fusion-node/data/efsn.ipc’

These can all be overridden using strings

Sanity Check

You can check that your installation has been successful as follows :-

from  web3fsnpy import Fsn

linkToChain = {
    'network'     : 'testnet',                          # One of 'testnet', or 'mainnet'
    'provider'    : 'HTTP',                             # One of 'WebSocket', 'HTTP', or 'IPC'
    'gateway'     : 'default',                          # Either set to 'default', or uri endpoint
    #'private_key'     : os.environ["FSN_PRIVATE_KEY"],  # comment out for just read operations


web3fsn = Fsn(linkToChain)

print('Current block height is ',web3fsn.blockNumber)