Hire the Best Cryptocurrency Freelancers
in Spain

14+ years of delivering linguistic precision for global industry leaders. As a member of the National Association of Graduates in Translation and Interpreting (CONALTI, Venezuela) (member association of the International Federation of Translators (FIT/IFT)), I bridge the communication gap between complex technical sectors and the Spanish-speaking world. My approach combines a deep architectural background with cutting-edge AI-integrated workflows to deliver translations that are not only accurate but culturally and strategically impactful. Why partner with me? I don’t just translate words; I localize experiences and secure compliance. My expertise is built on three high-stakes pillars: EdTech & Gamification: During my tenure at Duolingo and Amino Apps, I localized entire app ecosystems and curricula for millions of users, specializing in Linguistic Quality Assurance (LQA), gender-agreement audits, and cross-dialectal adaptation (Spanish MX, AR, ES, CO, VE). Fintech, Crypto & Web3: At Deriv and through Contentoo, I specialized in high-complexity trading platforms, blockchain terminology, and AML/Compliance content, achieving a consistent 100% quality score. Legal, Healthcare & Public Sector: Long-term collaborator for The Spanish Group and Baystate Interpreters, managing sensitive vital records (USCIS/Embassy standards), IEPs, and social housing documentation with strict confidentiality (HIPAA/FERPA-compliant). Technical Mastery: I leverage a robust CAT Tool stack (MemoQ, Phrase, SmartCat, Crowdin, Transifex) and Generative AI (Prompt Engineering) to optimize turnaround times while maintaining the highest stylistic integrity. Core Specialized Areas: Engineering & AEC: 11-year tenure as the lead translator for the Advanced Building Skins International Conference. iGaming & Marketing: SEO-driven localization and transcreation for B2B and B2C global campaigns. Digital Excellence: Expert-level LQA, functional bug reporting, and subtitle synchronization. Let's connect if you are looking for a proactive, tech-savvy linguist who understands that in localization, precision is the ultimate ROI.

Introduction: I am a passionate and dedicated cryptocurrency enthusiast with a focus on blockchain technology. Since January 2021, I have been actively learning about the industry through reading, following news, and engaging in different crypto networks and protocols. I have always embraced a “white-belt” mentality, constantly trying to improve and learn. This, I believe is what made me land my first Web 3 job after a relatively short time. Further, my past year working full-time in the industry has constantly challenged me to keep learning in order to deliver, as my responsibilities and tasks have also developed over time. Certification: In August 2022, I earned my certification as a Certified Blockchain Expert from the Blockchain Council. This certification is available on my Upwork page and validates my knowledge and expertise in the blockchain industry. Work Experience (relevant for crypto): Since October 2022, I have been working in the crypto industry, where my first task was to conduct deep analysis of upcoming crypto projects, including presales, ICOs, IDOs, and SHOs. In addition to this, I have been writing articles about the current state of the crypto market, as well as tracking "smart money" wallets to stay up-to-date on buying and selling trends. Together with a developer, I made a smart wallet tracker, where I currently have around 300 confirmed smart wallets and get every purchase they make sent to my Telegram. Through my own interest in learning On-Chain analysis, I have checked each wallet on things such as volume and profitability. Skills: I possess a strong general understanding of the crypto market and its various trends, a part of my tasks has been to write articles about current and upcoming trends (Please note these trends have most probably shifted since writing this) in the crypto space, including AI, DeFi 2.0, Optimistic Rollups, ZK-Rollups, GameFi, Asset Tokenization, Perp Dexes, Digital Identities, and Payment Solutions, to mention a few. I also have a basic knowledge of Solidity, allowing me to identify specific functions in smart contracts that could be potential issues when ex engaging with micro-cap crypto protocols on decentralized exchanges. Currently learning more On-Chain analysis to further deepen my skillset in the Web 3.0 industry Passion: My spare time is dedicated to researching various crypto projects for personal interests, and I can confidently say that I live and breathe cryptocurrencies and blockchain tech.

I'm a senior product engineer with 15+ years building web products, working AI-native. With a design background, I own product, design, and engineering end-to-end and ship user experience that moves business outcomes: conversion, retention, revenue. I work embedded with founders and teams as a long-term partner. Multi-year client relationships across SaaS, fintech, and AI-native products. What I build: Agentic AI products and LLM-powered features (RAG, multi-agent pipelines, Claude and OpenAI integrations) SaaS dashboards, internal tools, and B2B platforms Fintech products with API integrations (Stripe, Binance, QuickBooks, banking APIs) Full-stack platforms with data sync pipelines and complex integration layers Stack: Next.js, React, TypeScript, Node.js, Python, FastAPI, PostgreSQL, MySQL. AI tooling: Claude Code, Codex, MCP, BMad Method, agentic workflows on Cloudflare. How I work: I like to get close to the problem. Not just what we're building, but why, and for whom. I bring ideas throughout a project, stay close to user feedback, and sometimes the best contribution is helping simplify what's already on the roadmap. Some of the features I've proposed became the most-used parts of the platform. Before going freelance, I founded and scaled a $5M+ e-commerce business, owning product, engineering, and brand end-to-end. So you get clean execution plus solid product thinking and design instincts. What clients say: "What sets him apart is how he seamlessly combines UI and UX considerations with robust functionality." (George C. Huang, M.D., Profit Stash) "Very talented developer who communicates well, reliable, and thinks entrepreneurially. He'll present ideas and offer suggestions on how to improve existing ones." (Cameron W., WeNomad) "One of the best people I've worked with. He's responsive, creative, works autonomously, and is easy to talk to. He significantly improved the app I was building with his own ideas for speed and design." (Benji E., Harmonic Intelligence) I like to work in small increments: shipping smallest versions first so you can validate before scaling. So if you're looking for someone who gets close to your business, brings ideas, and ships product, let's talk.

I design, build, and operate production-grade systems that survive real users, real load, and real failures. WHAT I BUILD: AI & Real-Time • AI voice applications with real-time speech-to-text and multi-agent orchestration • AI chatbots with RAG pipelines and vector search in production • Real-time systems using WebSockets, SSE, and streaming APIs SaaS & Platforms • SaaS platforms with payments, OAuth, and role-based access control • Analytics dashboards with complex data visualization and real-time updates • CRM integrations and workflow automation for operational efficiency Backend & Infrastructure • Node.js backend services (Express, cron jobs, queue workers) • ML training pipelines with serverless GPU compute at scale • Blockchain and crypto minting workflows Desktop & Extensions • Cross-platform desktop apps with Electron (Windows, macOS, Linux) • Browser extensions with Plasmo (Chrome MV3) TECH STACK Frontend • Next.js, React, TypeScript, Tailwind • Electron, Plasmo (Chrome MV3) Backend • Node.js, Express.js, Python (FastAPI) • Supabase, PostgreSQL (RLS), Prisma AI / ML • OpenAI API, Anthropic Claude, Whisper • LangChain, pgvector, TensorFlow Voice AI • OpenAI Realtime API • Whisper STT, TTS, WebSocket voice streaming Infrastructure & DevOps • AWS, Google Cloud, Cloudflare • Docker, Kubernetes, Terraform, Nginx • CI/CD, Vercel Queues, Caching, Realtime • RabbitMQ, BullMQ • Redis, edge caching • WebSockets, Server-Sent Events Security • OAuth 2.0, OIDC, JWT • API security, rate limiting, RLS ARCHITECTURE EXPERIENCE • Microservices, DDD, CQRS, Clean & Hexagonal Architecture • Multi-service ecosystems: API servers, GPU workers, dashboards • Secure data flows: OAuth ingestion, validation, vector storage, RAG retrieval • Event-driven systems: async jobs, queues, webhooks, SSE progress • High-scale batch processing: 100k+ records with parallel GPU workers (H100 ×10)

🥇VERIFIED TOP 1% Designer on the Upwork. 🧑‍💻 10+ years of experience in UX/UI design for SaaS Web Applications. 💼 Clients: Toyota, DJI, Tesla, Johnson & Johnson, Helly Hansen, Siemens, Nikon, Inditex. For over 10 years, I have specialized in product design for complex b2b/b2c web applications. I create and improve products such as CRM, ERP systems, dashboards, and other advanced platforms. I can design an MVP from scratch, enhance an existing MVP as the product grows, or redesign large-scale enterprise applications. ⚠️Send me the details of your project, and I’ll be able to provide you with a FREE rough estimate. ⚡️I can also offer a quick, FREE UX/UI audit of your current project and then provide an estimate based on that. 📩Just сontact me here right now and I will answer you within 5-20 minutes My typical design process and methods: 1️⃣ Project Onboarding & Cost Estimation I review all project materials and documentation, dive into your product and goals, and identify key challenges. Based on this, I create a clear step-by-step project plan with phases, timelines, and dependencies, and provide a transparent estimation of hours and total cost. You receive a structured roadmap showing what we start with, what follows next, how the project is broken down by stages, how long each stage takes, and when each phase will be delivered. ⚡️ Sitemap & Functional Requirements (Optional) If user scenarios (User Stories) are provided, I create a structured sitemap outlining all modules and their main functions. This visual map clearly shows how sections relate to each other, the flow between screens, and the key requirements for each module. 2️⃣ Research and UX & Usability Audit • UX & Usability Audit I review the existing application to identify friction points, unclear user flows, and areas where users may get stuck. All findings are delivered with annotated screenshots highlighting issues and recommendations. • User Behavior Analysis Using Hotjar, Google Analytics, and other tools, I analyze real user interactions through session recordings, heatmaps, and collected user feedback to validate assumptions, identify pain points, and uncover opportunities for improvement. • Competitor Analysis I analyze competitors to identify strengths, weaknesses, and opportunities, uncovering gaps and potential areas for improvement. 3️⃣ UX Part. Low-Fidelity Wireframing I create low-fidelity wireframes for each screen and user flow to validate functionality, logic, and overall structure before visual(UI) design begins. These wireframes define content placement, interaction patterns, and layout based on user needs and business goals. 4️⃣ UI Component Libraries & Style Guides I define the design system for your product, choosing from popular frameworks such as Material UI (MUI), Tailwind UI, Ant Design (AntD), React Bootstrap or Element UI, based on project requirements and scalability. This includes creating a comprehensive style guide that documents typography, colors, spacing, and how each component functions, enabling developers to maintain consistency and simplicity in future design and development. 5️⃣ UI Design I create the high-fidelity visual design of the product, including typography, color palette, imagery, and iconography. All screens are delivered ready for development, with consistent layout, style, and interaction details. 6️⃣ Prototyping – Clickable Prototypes Once high-fidelity UI designs are ready, I create clickable prototypes in Figma or Claude.ai, linking all screens and user flows. These interactive prototypes simulate the real product experience, allowing stakeholders and users to navigate through the app, test functionality, and validate the design before development begins. 7️⃣ Usability Testing – Prototype Validation I conduct usability tests on the interactive prototypes to evaluate the ease of use, clarity of user flows, and overall experience. This allows us to identify and fix potential usability issues before development starts, ensuring the product is intuitive, efficient, and aligned with user needs. 8️⃣ Development Support & Handoff I prepare all Figma designs for development with detailed specifications, including component states (Error, Empty, Loading) and all necessary assets. 9️⃣ Project Support & Design Supervision After the design is completed, I continue to support the project by supervising the implementation and ensuring design quality throughout the development cycle.

🤝 Welcome to my profile! I'm Oscar, a dedicated freelancer with a passion for language and a diverse skill set. I offer a range of services, including translation, proofreading, transcription, content writing, subtitling, AI training, and voice recording. 🗣 Languages have always fascinated me, and I pride myself on being a polyglot. As a Barcelona native, I am fluent in Spanish and Catalan, my native languages. I have also had the privilege of living in Montreal, Canada, which further expanded my cultural horizons and enhanced my English skills to a near-native level. Moreover, my adventures in Asia, including living in Korea and exploring various cities in China and Vietnam, have allowed me to achieve a high level of proficiency in Chinese and Korean, languages that I keep learning and have reached a C1 level. As for my studies, I will be graduating in International Relations this year and starting a master's degree in World Affairs next year. 💼 Professionally, I have had the opportunity to work with prestigious companies, refining my expertise and gaining valuable experience. During my career, I have excelled in translating various formats, including websites, e-shops, newsletters, social media, and literature. I am adaptable and versatile, specializing in translating business and marketing documents, video captions, and even localizing video games. 🌟 Some of my notable translation projects include collaborations with renowned companies such as Zumub, a well-known sports nutrition e-shop, Moonactive and ChillBase, both prominent video game companies. I have also worked with Metalshop, a leading clothing e-shop, Kulina, a home appliances e-shop, and Locx Labs, a digital marketing agency. Additionally, I have worked on the translation of books such as the guide to passing the US citizenship test, Juliette Swann's romantic self-help saga or Nikolai Bugaev's biography. These experiences have enriched my skills and deepened my understanding of various industries. ✍️ In addition to translation, I am a skilled content writer, adept at crafting engaging and creative pieces. I have spent several years as a content writer for Full Esports, a Spanish esports website, where I honed my abilities in producing captivating articles and blog posts. One of the areas I have recently improved in is SEO. I possess a deep understanding of SEO techniques and strategies, allowing me to optimize your content for maximum visibility and impact. 🎯 When you work with me, you can expect professionalism, meticulous attention to detail, and timely delivery. I have a knack for adapting to diverse formats and industries, ensuring that your projects meet the highest standards. 🚀 If you're looking for exceptional translations or captivating content, among other things, I'm here to help. Let's collaborate to elevate your projects to new heights!