Understanding the Celo Tech Stack


Hello, everyone! Welcome to our deep dive into the Celo tech stack. Today, we are going to embark on a journey that explores the intriguing components of the Celo blockchain and what makes it truly unique. Don’t worry about being a newbie or an experienced developer, our discussion caters to all experience levels. Let’s kick start this journey!

Understanding Blockchain Primitives

Diving into the world of blockchain, it is crucial to comprehend some fundamentals that give this technology its unique attributes. A blockchain environment presents a novel paradigm in application development, offering a spectrum of opportunities as well as challenges.

In the blockchain realm, the two main types of accounts that you’ll often interact with are Externally Owned Accounts (EOAs) and smart contract accounts. EOAs are typically controlled by individuals or computers, and they’re different from smart contract accounts, which contain code and behave differently.

One of the cornerstones of blockchain technology is the concept of transparency and public verifiability. In a blockchain like Celo, every transaction is publicly viewable and cryptographically verifiable using public key cryptography, creating a layer of reliability and security. Additionally, to prevent network spam, transactions cost real money, creating an incentive to make transactions valuable.

Another key component is nodes, the actual computers running the blockchain. Celo is a peer-to-peer network, and all peers replicate the state of the blockchain on their machines. Notably, Celo has developed a lightweight client that can run on low-end Android devices, embodying its mission of making blockchain accessible to a wider audience.

The Unique Aspects of Celo

Celo stands out as an independent Layer 1 blockchain, incorporating updates and improvements made by the Geth team into its own iterations. It’s important to note that the utilization of blockchain technology is ideal when you need publicly viewable, cryptographically verifiable information. Celo is designed to handle this efficiently, allowing for a more effective storage of data on chain.

Moreover, Celo, like many other blockchains, supports Ethereum Virtual Machine (EVM), which fosters an ecosystem of interoperability and developer tool composability. A key feature is that Celo allows gas payments in multiple currencies, making it a more user-friendly platform for transactions.

A unique aspect of Celo is its ability to link phone numbers to Celo addresses on the network. This offers a convenient way for users to engage with the network, reducing the barriers of complex alphanumeric addresses. It’s an essential step towards mass adoption of blockchain technology.

Celo’s implementation of a token bridge is a game-changer, enabling tokens to move seamlessly from one chain to another. This cross-chain interoperability opens up a multitude of possibilities for developers and users alike.

Celo Smart Contracts

As we delve deeper, let’s explore Celo’s unique smart contracts. As developers, you’ll appreciate that smart contracts are not just about transactions, they are programmable applications in their own right. Simply put, they’re public state machines that follow a set of pre-defined instructions. Once they’re deployed on the chain, anybody can read their state, making any information contained within them publicly accessible. That said, remember that all the magic happens off-chain; the blockchain is just for final settlement and computation. The beauty of this is that it brings about a new kind of open-source development environment. Smart contracts can freely interact with each other in a trusted manner, expanding the possibilities of what we can create. OpenZeppelin, for instance, offers a library of standardized smart contract templates that can be easily customized and safely deployed on the Celo network.

Celo’s Relationship to Ethereum

Now, let’s address a frequently asked question: Is Celo independent or does it depend on Ethereum updates? In short, Celo is an independent layer one blockchain. Yes, it has forked from Ethereum’s Geth, but the blockchain team at Celo is actively merging any essential updates from Geth into their current versions. This way, Celo harnesses the ongoing progress in the Ethereum ecosystem while maintaining its independence and unique features.

Celo Core Contracts

Our exploration wouldn’t be complete without discussing Celo’s core contracts. Notably, Celo’s native stable currencies, like Celo Dollars and Celo Euro, are implemented at the core contract layer. The native stablecoins have become quite popular among developers for their value stability, making them ideal for various applications on the network.

EVM Compatible

Shifting focus to Celo’s unique features, there are several aspects that set it apart from other blockchains. First, Celo supports EVM (Ethereum Virtual Machine), increasing the chain’s compatibility with existing Ethereum tools and smart contracts. In fact, developers can effortlessly migrate their Ethereum smart contracts to Celo, thanks to this feature. Second, Celo has natively implemented multi-currency support, allowing users to pay for transaction fees in Celo dollars or Celo euro, eliminating the need for multiple currencies in a wallet to pay for transactions. Third, Celo’s ultralight synchronization allows the blockchain to operate efficiently even on low-end Android devices, extending its reach to new markets and audiences. Lastly, Celo operates on a proof-of-stake consensus, which not only renders it energy efficient but also offers stakeholders the potential to earn annual returns by voting for validators.

Lightweight Identity Layer

Next, let’s highlight Celo’s lightweight identity layer. It’s a revolutionary feature that allows a Celo address to be linked with a phone number. This functionality paves the way for user-friendly transactions as users can transfer funds to others using their phone numbers instead of complex blockchain addresses. Furthermore, the lightweight identity layer could also facilitate more sophisticated features such as token bridges, enabling seamless cross-chain transactions.

How to Leverage these Features

But, how can you, as a developer, best leverage these features? That’s where understanding DApp architecture and Web 3.0 is key. Building on blockchain technology presents a paradigm shift from traditional web (Web 2.0) development. Here, you are dealing with a decentralized, permissionless network where access control must be managed through tokens or other authentication means. Your users’ gateways to your application are crypto wallets, not just for payments but also for interacting with your DApp. One huge benefit of the way Web 3.0 has been evolving is that many of the tools and frameworks from Web 2.0 can be readily used in the Web 3.0 environment.

Developer Tooling

Finally, let’s talk about the specific tools that developers use with Celo.

Celo SDK

Celo SDK is a prominent one, allowing developers to build applications on the Celo blockchain. It provides JavaScript libraries that interact with the smart contracts on Celo. These libraries allow you to connect your DApp to the Celo network, send transactions, interact with smart contracts, handle multi-signature wallets, and much more.


One more critical tool is Truffle, a development framework for Ethereum that you can use with Celo due to its EVM compatibility. Truffle allows you to compile, deploy, and test your smart contracts in an easy and organized manner. It offers built-in smart contract compilation, linking, deployment, and binary management which can significantly simplify the process of developing a DApp.


Another powerful tool in your arsenal is Ganache, a personal blockchain for Ethereum development. You can use it to deploy contracts, develop your applications, and run tests. It is available both as a desktop application and a command-line tool. Ganache provides you with a number of powerful features, such as advanced mining controls and built-in block exploration.


Metamask is another important tool to mention. It is a crypto wallet and gateway to blockchain apps. Metamask allows users to interact with your DApp through their browser or mobile application. It’s crucial for testing and deploying your application as it gives you a way to interact with it in a user-friendly way.

The Graph

Last but not least, let’s mention The Graph. It’s an indexing protocol for querying networks like Ethereum and now Celo. If you’re building a DApp, you will need a way to efficiently access the blockchain data. The Graph helps you do just that - it allows you to create and publish open APIs, called subgraphs, that applications can query using GraphQL.


So, as you embark on your journey as a developer on the Celo network, remember to leverage these tools and the unique features of Celo to build innovative and user-friendly applications. From its emphasis on financial inclusivity and real-world use cases to its unique capabilities like the lightweight identity layer, there’s a lot to explore and create on the Celo blockchain. Good luck with your development!