ETHBarcelona

This workshop will take you through a run down of zkSync's Paymaster and will allow pay your transactions with USDC (or any token) using API3's dApi price feeds while also allowing the options of allowing free transactions to any holder of a specified VIP NFT.

API3

Developer Relations

Billyjitsu

Use API3's dApi price feed in zkSync's paymaster

Opening

Team Formation

Hot and Fresh dinner served for your bellies!

Dinner Day#1

In this two part workshop, attendees will learn about how Scroll is scaling Ethereum with its zkEVM. First, you’ll see how easy it is to deploy your contracts to Scroll using a handful of popular developer tools. In the second half of the workshop, attendees will learn how to use Scroll to verify zero-knowledge proofs built in Noir, building a zk voting app. Part 1 will be in English, with Part 2 done in Spanish.

Scroll

Raza Zaidi

Ahmed Castro

Building on Scroll – from beginning to AppliedZK (English & Spanish)

Sharing experiences and best practices on setting up, scaling and running nodes / validators, including monitoring and alerting based on open source products

Gnosis

Cloud Engineer

Anton D.

Running Gnosis nodes and validators

Join Anthony DiPrinzio and Nse Barna from Aleo as they provide an introductory lesson on zero-knowledge (ZK) technology and how it can be applied to real-world use cases. They will also include a high-level overview of Aleo's architecture, domain-specific programming language ([Leo](https://leo-lang.org/)) and a deep dive into how ZK technology will form the building blocks for the next wave of decentralized applications. If you’re a developer interested in building private, programmable applications this is the workshop for you!

Aleo

Head of Ecosystem Growth

Anthony DiPrinzio

Chief of Staff

Nse Barna

Demystifying ZK Programming: Decentralized Private Computations on Aleo

In the era of digital assets and blockchain technology, we present an immersive, hands-on workshop that aims to deepen your understanding and skills in the exciting world of Non-Fungible Tokens (NFTs) and staking mechanisms.

The workshop is tailored to cater to artists, investors, developers, and enthusiasts alike who are interested in delving into the transformative potential of NFTs and how they interact with the dynamic mechanism of token staking.

Participants will explore the conceptual and technical aspects of creating unique NFTs with various levels and rarities. Through this journey, you'll understand the profound layers of blockchain technology and how it is revolutionizing the digital landscape.

In addition, we'll unravel the process of creating a specific token for staking purposes, enabling attendees to understand how to stake these tokens within their uniquely created NFTs. This not only adds value and utility to your digital assets but also provides an opportunity to gain insights into the economic models within the blockchain ecosystem.

**Key Workshop Takeaways:**
- Comprehensive understanding of NFTs and their intrinsic properties.
- Hands-on experience in creating unique, multi-level NFTs with various rarities.
- Insight into the concept and process of token staking within NFTs.
- Step-by-step guidance on creating a staking token specific to your NFTs.

Create your piggy-bank NFT! by XDC Network

Take a break from building to grab some lunch!

Lunch Day#2

Endaoment invites developers & builders for good to a workshop exploring use cases & applications for new web3 tooling that makes crypto giving flow. Learn how to find contract addresses for global organizations, format donation transactions and deploy new contracts for nonprofits. If you're passionate about bridging web3 and impact, join the Endaoment.Tech team to learn about our new developer tools and innovate together live, as a community. #consciouscrypto

Endaoment

President & CEO

Robbie Heeger

Onchain Programmatic Giving with Endaoment’s SDK

Learn the core pieces of the Union credit protocol, How smart contract based credit underwriting and borrowing work. And a practical example of  How to build a contract that autonomously underwrites any address that holds a specific NFT.

Union Finance

Founder

Jacob Shiach

How to build on Union

The introduction of Account Abstraction to the zkSync Era scaling solution realizes the concept of smart contract accounts (SCAs) for functionality such as social recovery, spending rules and flexible validation. 

Paymasters enable gas in ERC20 to be paid from a separate contract, basically enabling gasless transactions. At the moment, the majority of EVM-based Externally Owned Accounts (EOAs) have a self-custody model, meaning they cannot utilize a paymasters contract. However, on zkSync Era paymasters can be utilized by both EOAs and SCAs. 

Use zkSync’s paymaster with dAPIs to power existing dApps on zkSync Era

dAPIs can be used within zkSync’s Paymaster contract to enable users to pay for gas in any token of their choice on your platform. Within a paymaster, dAPIs can provide price data on-chain for execution.

Participants are required to implement a custom API3 zkSync’s paymaster within their projects that can sponsor the gas fee for users’ transactions on their dApps/platforms.

Participants can follow the [Paymasters with dAPIs on zkSync](https://github.com/vanshwassan/zk-paymaster-dapi-poc) guide to implement your ideas around the same.

Resources: 

- [Using dAPIs on zkSync Era Testnet](https://vanshwassan.medium.com/using-dapis-on-zksync-era-testnet-30f12efdd95f)
- [Hello World on zkSync Era Testnet](https://era.zksync.io/docs/dev/building-on-zksync/hello-world.html)
- [zkSync Paymasters Integration](https://era.zksync.io/docs/dev/tutorials/api3-usd-paymaster-tutorial.html)

📣 Utilizing API3 data feeds within zkSync Era's Paymasters

Dinner served hot and fresh before your late-night codesprint!

Dinner Day#2

Get your energy levels up for the final codesprint!

Breakfast Day#3

Yellow is proud to sponsor ETHBarcelona's Demo Day Breakfast! 

Join us for a morning of innovation and blockchain awesomeness as we warm up to pitch 🥐💡

Yellow, a team led by some blockchain pioneers, focuses on state-channel infrastructure, DeFi, and liquidity, revolutionizing the next-gen DeFi experience and supporting developers and entrepreneurs. 

If you want to learn more about how Yellow is decentralizing trading for real: www.yellow.org TG: @yellow_org. 

Connect with Yellow at ETHBarcelona's Special Demo Day Breakfast!  💛