Blockchain Developer at Umbrella Research · Founder & Tech Lead at BitChill
Production-minded Web3 engineer with a software background and master's degrees in Industrial Technologies and Automation/Robotics from the Technical University of Madrid. Since 2022 I've been building in Web3 while working full-time, focusing on smart contracts, DeFi integrations, and turning ideas into working products.
The strongest (public) proof of my work is BitChill: an automated, non-custodial and yield-bearing DCA dApp for bitcoin on Rootstock that is live on mainnet, has real users and TVL, and grew from a hackathon win into a grant-funded product. That mix of product delivery, smart contract development, and public technical work is what I bring to new collaborations.
Reach out: ynyesto@gmail.com · LinkedIn
Open to: part-time and contract collaborations around smart contracts, DeFi, and protocol-facing products.
| Project | My role | Why it matters |
|---|---|---|
| Umbrella Research | Blockchain Developer | Build back-end systems and protocol integrations for DeFi workflows, working mainly in TypeScript with regular Solidity and on-chain data exposure. |
| BitChill | Founder and Tech Lead | Shipped an automated, non-custodial and yield-bearing DCA dApp to Rootstock mainnet with real users and TVL. Winner of the Vottun & DexTools Hackathon and later backed by a Rootstock grant. |
| ETHGlobal Bangkok - Migrator | Smart Contract Developer and pitch lead | Built the CCIP part of an ERC20 L1 to multichain L2 migration tool. Won Chainlink Best Use of CCIP, Scroll L1SLOAD 2nd place, and Blockscout pool-prize. |
| Tropykus (Immunefi) | Bug bounty submission | Paid low-severity finding on Tropykus via Immunefi. POC and writeup. |
| FilmChain Vesting | Freelance Smart Contract Developer | Delivered a production vesting contract for early investors and team allocations. |
- Production delivery: I have shipped a real Web3 product to mainnet, which I developed end to end and currently has active users and TVL.
- Protocol-facing work: My work spans smart contracts, DeFi integrations, on-chain data, back-end systems, and some front-end.
- Security mindset: I have completed Cyfrin's security track, published Ethernaut and CTF writeups, and performed multiple audit-style reviews.
- Public proof of work: Hackathon wins, freelance delivery, technical challenges, and research/writing all point to execution in public.
- Confidential work: My work on my current full-time job at Umbrella Research is confidential, and since all the repos are private they can't be featured here.
| Event | Project | Result |
|---|---|---|
| ETHGlobal Bangkok | Migrator | Blockscout prize, Chainlink Best Use of CCIP ($4,000), Scroll Best Use of L1SLOAD 2nd place ($1,500) |
| Vottun & DexTools | DCA Bitcoin dApp | 1st prize, later became BitChill |
| Block & Change | Repo | Best social innovation |
| Constellation Chainlink | Prompt Fighters | Team project with Devpost submission |
- VaultGuardians audit: capstone audit of an ERC-4626 project covering manual review, static analysis, fuzzing, and reporting.
- Ethernaut writeups: Level 32 - Impersonator, Level 33 - Magical Animal Carousel.
- The Rekt Games writeup: learning artifact for the Ethereum Foundation Devcon Scholars Program.
- PBS research entry: contribution to the Ethereum Protocol Fellowship Study Group, also published as a HackMD post.
- Chorus One research piece: quantitative research directions for staking providers in 2024.
- pk-keychain-management: local key management so private keys never live in
.env. - ERC-Conditional-Tokens (EIP contribution): contributed to an EIP for conditional tokens; still early and not yet widely adopted.
- Cyfrin Updraft Security Track: Smart Contract Security course and Assembly & Formal Verification course.
- Uniswap Hooks Incubator: five workshop hooks plus a BitChill-related capstone hook.
- Chainlink: CCIP Bootcamp and RWA Bootcamp.
- Alchemy University: Ethereum Developer Bootcamp, including the SummerPay final project.
- Cyfrin Updraft Foundry track: ERC20s, NFTs, stablecoin, CCIP rebase, merkle airdrop, proxies, account abstraction, DAOs, and security-focused exercises.
More repos and coursework
- PasswordStore audit
- PuppyRaffle audit
- TSwap audit
- ThunderLoan audit
- BossBridge audit
- VaultGuardians audit
- Cyfrin Updraft – Aave V3 exercises
- Foundry L7 – Fund Me
- Foundry L9 – Lottery
- Foundry L10 – ERC20
- Foundry L11 – NFTs
- Foundry L12 – Stablecoin
- CCIP Rebase Token
- Merkle Airdrop
- Foundry L13 – Upgradeable contracts
- Account abstraction
- Foundry L14 – DAOs
- Foundry L15 - Security
- Road to Web3 – ERC721 NFT
- Road to Web3 – Buy Me a Coffee dApp
- Road to Web3 – On-chain metadata NFTs
- Road to Web3 – NFT Gallery
- Road to Web3 – Dynamic NFT with Chainlink
- Road to Web3 – Staking dApp
- Podproza technical challenge: Bitcoin chain analytics with Python.
- TruWeb3 cross-chain mirror: ERC20 cross-chain mirror built with TDD and Chainlink CCIP.