Did you know that blockchain applications, also known as decentralized applications (or “dApps” for short), can now be built in native Python? Blockchain development has traditionally required learning specialized languages, creating a barrier for many developers… until now. AlgoKit, Algorand’s all-in-one development toolkit, enables developers to build blockchain applications in pure Python.
In this article, we’ll discuss the benefits of building blockchain applications, why Python is the best choice for dApp development, how to set up your blockchain development environment, and how to get started building secure blockchain applications in native Python.
Why build a blockchain application?
Blockchain application development goes far beyond creating distributed databases and peer-to-peer transactions: it brings new levels of reliability, security, and efficiency to a wide range of applications.
Tamper-proof records guaranteed: Blockchain creates an immutable and transparent ledger, ensuring data security and eliminating the risk of tampering.
Automate complex agreements: Smart contracts and atomic swaps eliminate the need for third-party verification, streamlining transactions and reducing costs.
Transforming asset ownership: Digitization allows for fractional ownership and secure trading of real-world assets.
Build innovative solutions: Python development skills allow you to create groundbreaking applications in AI, identity management, and secure IoT data exchange.
Why use Python to build blockchain applications?
Readability and maintainability: Python’s smooth syntax and robust tools make it easy to write, understand, and modify code, especially when working on complex and powerful blockchain projects.
Integration with other technologies: Python works well with other technologies that are often used in conjunction with blockchain, such as web development frameworks and machine learning libraries, which allows you to build dApps that go beyond the core functionality of blockchain.
World-Class Developer Experience: Python has a large and active developer community, plus first-class, comprehensive documentation and powerful tools supporting Python and blockchain development.
How to set up your development environment to start building blockchain applications
The easiest way to build blockchain applications in Python is to download and install AlgoKit, a one-stop toolkit for building, launching, and deploying secure, production-ready decentralized applications on the Algorand blockchain.
AlgoKit allows you to set up your development environment and project folder and start building your project with a single command.
Download and install prerequisites
Make sure you have Python 3.12 or higher, pipx, Git, and Docker installed. On macOS, you’ll also need to install Homebrew.
Install AlgoKit
Open a command line/terminal and type “pipx install algokit”. This will install AlgoKit and make it available in the directory of your choice.
Build a local blockchain network
You can try out a private version of the Algorand blockchain on your computer.
In your command line/terminal, type “algokit localnet start”. This will create a local blockchain network running in a container using Docker. You can then check the Docker desktop app to see if it’s running.
To launch a browser-based blockchain explorer and visualize what’s going on in this local network, type “algokit localnet explore.”
Create a new project
Now that AlgoKit is installed, we can create a new project for our blockchain application.
First, run “algokit init”, which will launch a guided process where you’ll be asked a few simple questions to set up your project.
If this is your first time, start by selecting “Smart Contract” to indicate that you are building a smart contract application.
Select “Python” as the language since we are going to write Python code, choose the name of the folder where we will store all the files of our project and the name of our application.
Finally, select the “Production” template to set up a project ready for deployment.
The Production template is like a pre-built starter kit for your Algorand project. It gives you a clear picture of how different parts like testing, continuous integration/continuous delivery (CI/CD), deployment, etc. work together in a complete Algorand project. Next, select Python again.
Answer Y to the next question and AlgoKit will install dependencies and initialize a Git repository.
Once the project generation process is complete, open the project directory in your preferred code editor.
How to Build Secure Blockchain Applications with Python
Examining the Code
The `Production` template includes a simple `hello world` smart contract located at `smart_contracts/hello_world/contract.py` that should be very familiar to Python developers, with a few key differences.
The first thing to note is that our `HelloWorld` class inherits from `ARC4Contract`. ARC4 is the Algorand Request for Comment #0004, which defines the Application Binary Interface (ABI) for Algorand methods. Inheriting from `ARC4Contract` ensures that our contract adheres to this standard used by many tools in the Algorand ecosystem, including AlgoKit itself.
Above the actual ‘hello’ method definition, there is also a ‘@arc4.abimethod’ decorator. This decorator exposes the method as a public method in the contract. Because it is an ARC4 ABI method, any tool that supports the ABI can easily call this method. AlgoKit also includes a client generator that can generate a Python or TypeScript client that interacts with all the ABI methods you define.
Finally, you’ll notice that the function arguments and return types are `arc4.String`. ARC4 also defines how to encode and decode data types when interacting with contracts. Because the Algorand Virtual Machine (AVM) does not support all the same features as Python’s `str`, we need to use the `arc4.String` type provided by the `algopy` module.
Compiling and building
“algokit project run build” allows you to compile smart contracts written in native Python into TEAL, a bytecode language that the AVM understands. The build also produces additional artifacts that can be used to facilitate interacting with the contract, as can be seen in tests.
Dialogue and testing
To see how contract interaction and testing works, navigate to “tests/hello_world_test.py”, where you can see that we are using the HelloWorldClient auto-generated by AlgoKit during the build step. This makes interacting with contracts very easy and can be leveraged in testing, backend, or frontend development.
Write the code
Once you’ve explored this project and run your first “Hello World”, you’re ready to build on Algorand. You can turn the sample contract into your own dApp, such as a marketplace, a manager of tokenized real-world assets, or an on-chain immutable data store.
Write your on-chain smart contract logic in contract.py and write related tests in “smart_contracts/tests”. Re-run “algokit project run build” to recompile, deploy and test your contract in seconds.
AlgoKit handles the boilerplate code and development environment configuration, so you’re ready to iterate rapidly while building your own application.
For a detailed tutorial on how to build Algorand in Python using AlgoKit, check out the AlgoDevs YouTube channel.
For more information on Algorand Python, see the documentation.
