Senior Backend & Smart Contract Engineer
Production systems · Protocol engineering · DeFi · Identity & security

Valencia, Spain · Remote-first · EMEA & international teams

I build software where state, permissions, money, identity, deadlines, and failure modes matter.

My background spans more than 15 years of engineering, from industrial automation and operational systems to backend, full-stack, mobile, and blockchain development. That path shaped how I approach software today: model the real rules first, keep state transitions explicit, constrain privilege, design for failure, and prove important behaviour with tests rather than assumptions.

My work now sits mainly at the intersection of:

• Backend & identity systems — Kotlin, Java, Spring Boot, PostgreSQL, Keycloak, OAuth2/OIDC, APIs, messaging, integrations, CI/CD
• Smart contracts & protocol engineering — Solidity, EVM, ERC-4626, signed intents, state machines, token flows, settlement, replay protection, security boundaries
• DeFi & programmable payments — Aave V3, Morpho, vault accounting, constrained rebalancing, allowances, pricing, self-custody and request-bound authorization
• Production product engineering — React Native, React/Next.js, TypeScript, mobile marketplaces, operational workflows and release delivery

I care less about adding blockchain to a product than about using it where verifiable state, programmable authorization, settlement, traceability, or shared trust genuinely improves the system.

These projects show four complementary sides of my engineering profile: DeFi infrastructure, protocol/security depth, end-to-end Web3 execution, and production delivery.

Risk-aware ERC-4626 yield optimization infrastructure for USDC on Base.

Adaptive Yield is a security-conscious DeFi protocol foundation that separates custody and enforceable risk constraints from future off-chain allocation intelligence. The public vault can hold idle USDC or allocate to approved strategies while enforcing strategy allowlists, percentage exposure caps, an idle-liquidity floor, bounded rebalancing, role separation, and emergency controls.

The current milestone integrates Aave V3 through a supply-only adapter and Morpho through a reusable ERC-4626 strategy, with both exercised against real Base protocol state through Foundry mainnet-fork tests.

28-test standard suite · 5,000-run fuzz property · 3 stateful invariants at 131,072 calls each
3/3 Base fork tests · Aave V3 + Morpho integration · Slither review · gas snapshot · consolidated GitHub Actions CI

The adversarial suite covers donation/inflation behaviour, fee-on-transfer rejection, reentrancy rollback, reverting strategies, short withdrawals, valuation failure, illiquidity, exposure limits, rescue restrictions, and emergency recall paths.

Stack: Solidity · Foundry · OpenZeppelin · Aave V3 · Morpho · ERC-4626 · Base · Slither · GitHub Actions

Source code · Architecture · Threat model · Economics · Testing

Experimental and unaudited. Adaptive Yield is not presented as production-ready financial infrastructure and has not been deployed with real capital.

Non-custodial EIP-712 signed limit-order settlement with partial fills, ERC-1271 and stateful Foundry invariants.

OrderForge is a security-focused Solidity reference protocol for off-chain signed orders and on-chain settlement. A maker signs an EIP-712 order; a taker can settle all or part of it without the protocol taking custody of funds.

The design covers the areas where signed-order protocols become interesting: domain separation, contract-wallet signatures, replay protection, nonce binding, cancellation, expiry, restricted takers, exact cumulative settlement and token-transfer failure semantics.

• EIP-712 structured signing bound to chain ID and verifying contract
• EOA + ERC-1271 signature verification through OpenZeppelin SignatureChecker
• Nonce binding and invalidation to prevent conflicting signed orders sharing lifecycle state
• Per-order cancellation, expiry and optional taker restriction
• Non-custodial settlement using direct SafeERC20 transfers and reentrancy protection
• Cumulative partial-fill accounting that reaches the exact signed buy amount at completion
• Explicit ABI/hashing examples with abi.encode, abi.decode, abi.encodeCall, abi.encodePacked and keccak256

44 Forge tests · 35 unit · 4 fuzz properties · 5 stateful invariants
4,096 fuzz runs/property · 65,536 calls/invariant · 100% production-contract line/statement/branch/function coverage
Slither: 0 results after documented narrow exclusions · protected main · stable v1.0.0 release

The adversarial suite covers mutated and malformed signatures, cross-chain replay, ERC-1271 rejection, false-returning ERC-20 rollback, overfill protection, partial-fill exactness and terminal lifecycle states.

Stack: Solidity · Foundry · OpenZeppelin · Slither · GitHub Actions

Source code · v1.0.0 release · Architecture · Threat model · Testing strategy

Educational/reference software. OrderForge has not undergone a professional smart-contract security audit and is not presented as production-ready financial infrastructure.

A transparent token-sale protocol with verifiable pricing, escrowed contributions, exact-asset refunds, and vesting.

LaunchProof is a full-stack Ethereum token-presale reference implementation built around a non-upgradeable Solidity protocol, deterministic deployment scripts, comprehensive Foundry testing, and a Next.js application that communicates directly with the blockchain.

The protocol supports ordered sale phases, native ETH and ERC-20 payments, Chainlink-compatible price feeds, purchase-time USD accounting, soft-cap finalization, cancellation, refunds in the original contributed asset, TGE unlocks, cliffs, linear vesting and liability-aware recovery rules.

The live V2 demonstration is deployed on Ethereum Sepolia with a fixed supply of 30,000,000 LPF, capped demonstration stablecoins, immutable demo feeds and a rate-limited faucet. The complete purchase path has been exercised on-chain from faucet claim through approval, purchase and LPF delivery.

Validation: 31/31 Foundry tests · 8/8 frontend tests · unit, fuzz, reentrancy, oracle-failure, lifecycle, vesting, recovery and stateful invariant coverage

Demonstrates: protocol architecture · escrow · refunds · phased pricing · oracle normalization · vesting · role boundaries · deterministic deployments · on-chain verification · Web3 UX

Stack: Solidity · Foundry · OpenZeppelin · Chainlink interfaces · Next.js · React · TypeScript · wagmi · viem · RainbowKit · Ethereum Sepolia · Vercel

Live application · Source code · Sepolia deployment

Educational reference implementation. The contracts have not been professionally audited and are not presented as production-ready financial infrastructure.

A production mobile marketplace connecting customers with nearby local kitchens.

Cooking is a two-sided product composed of Android and iOS customer applications and a dedicated Android manager application used by kitchens in day-to-day operations.

I contribute across customer flows, store operations and supporting API behaviour: marketplace discovery, maps, menus, favourites, cart state, authentication, sharing, ordering, kitchen workflows, notifications, product availability, automated testing, release configuration and production troubleshooting.

What makes the project valuable from an engineering perspective is not a single framework; it is maintaining coherent state across customers and kitchens while handling platform-specific behaviour, native dependencies, asynchronous data, operational failure modes and app-store delivery.

Demonstrates: production software · two-sided marketplaces · cross-platform reliability · operational workflows · state management · automated mobile testing · release engineering

Stack: React Native · Expo · TypeScript · Expo Router · TanStack Query · Jotai · Supabase · EAS Build · Jest · Maestro

Case study · Product website · Google Play · App Store

Security-aware Uniswap V2 integration with slippage protection and reproducible fork testing.

A focused Solidity + React project covering router quotations, exact-input swaps, minimum-output protection, deadlines, temporary allowances, receipt handling, behavioural mocks and pinned Arbitrum fork tests against deployed contracts.

Stack: Solidity · Foundry · OpenZeppelin · React · TypeScript · wagmi · viem · Arbitrum · Anvil

Interactive demo · Source

Policy-controlled HTTP 402 payments for autonomous AI agents.

Request-bound payment authorization with merchant allowlists, spending limits, expiration, revocation, replay prevention, audit events and Casper Testnet proof recording.

Stack: TypeScript · Node.js · Next.js · Rust · Odra · Casper · Vitest

Live demo · Source · DoraHacks

Self-custodial treasury workflows for teams, squads and fan groups.

Turns contribution and expense approvals into exact, one-time payment capabilities evaluated through policy rules, with role-based approval, PaymentIntent authorization, WDK simulation and safe no-broadcast signing.

Stack: Next.js · TypeScript · Tether WDK · React · Vitest · GitHub Actions

Live demo · Source · DoraHacks

Winner of the Blockchain-based Turnaround Checklist challenge at Decode Travel Barcelona 2025.

A Camino Network / Vueling aviation workflow modelling task ownership, role permissions, operational deadlines, SLA/KPI computation, certification and ERC-721 reward badges as explicit smart-contract state transitions.

Stack: Solidity · TypeScript · Next.js · Camino Network · IPFS · ERC-721

Case study · Source

A Ganache-like local development environment for Casper applications.

Docker-based tooling around Casper CCTL with interfaces for accounts, blocks, deploys, events, logs and local RPC workflows, designed to shorten the smart-contract development feedback loop.

Stack: TypeScript · Rust · Docker · Docker Compose · CCTL · Casper

Case study · Source

Alongside public blockchain and product work, I build backend and identity systems with Kotlin, Java, Spring Boot, PostgreSQL, Keycloak, REST/OpenAPI, Docker, Gradle and CI/CD.

Representative engineering areas include:

• Identity federation, SSO, OAuth2/OIDC and role synchronization
• Custom Keycloak authenticators, event listeners, storage providers and client policies
• REST and gRPC service design
• PostgreSQL modelling and Flyway migrations
• Authorization and account-lifecycle rules
• External provider and blockchain integrations
• Background messaging and asynchronous processing
• Unit, integration and controller testing
• Production debugging, dependency upgrades, migrations and release workflows

1. Model the domain before the framework. Start with actors, assets, permissions, invariants, deadlines and failure modes.
2. Make state transitions explicit. Contract, API, database and UI states should be understandable and testable.
3. Treat trust boundaries as first-class design inputs. Signatures, tokens, wallets, identity providers, oracles and external APIs can fail or behave unexpectedly.
4. Prefer least privilege and narrow capabilities. Administrative power should exist only where the system genuinely requires it.
5. Preserve liabilities during failure. Refunds, claims, escrowed balances and outstanding obligations must survive cancellation and recovery paths.
6. Test properties, not only examples. Unit tests explain behaviour; fuzzing and invariants challenge assumptions across larger state spaces.
7. Document what the system does not guarantee. Limitations, unsupported token behaviour, deployment status and audit status should be explicit.
8. Keep architecture understandable under pressure. Security and reliability improve when the state model can still be reasoned about during incidents and changes.

• Risk-aware ERC-4626 allocation across lending and yield strategies
• Signed intents, settlement and replay-safe authorization
• Stateful invariant testing and adversarial smart-contract verification
• Secure token distribution, escrow, refunds and vesting
• Programmable payment policies and autonomous-agent commerce
• DeFi integrations and reproducible fork environments
• Identity federation and policy-driven authorization
• Blockchain-backed operational workflows where shared verifiability has real value

Backend systems. Smart contracts. DeFi. Identity. Production software.

Portfolio · CV · LinkedIn · Contact