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Malt Strategy
Emiliano SebastianES

Emiliano Sebastian

Senior Software Engineer

€320/day
Barcelona, ES
8-15 years
Java
React Native
AWS
QA testing
Typescript

Average response time: 1 hour

About Emiliano

Senior Full-Stack Engineer and Tech Lead with over 15 years of experience architecting high-throughput backend systems, building cross-platform mobile apps, and deploying cloud-native solutions.

As the solo founder and developer of a live, AI-powered mobile app, I bring an entrepreneurial, product-focused mindset to freelance projects, ensuring clean code, rigorous testing (mutation/E2E), and smooth third-party integrations (including LLMs/Claude API).

How I can help your business:

Backend & Architecture: Java, Spring Boot, Apache Kafka, Microservices, and Event-Driven Design.

Frontend & Mobile: React, React Native, TypeScript, and high-performance UI components.

Cloud & DevOps: AWS, Azure, CI/CD pipelines, and cost-optimization.

AI/LLM Integration: Adding intelligent features and agentic pipelines to existing software.

  • English

    Fluent

  • Catalan

    Conversational

  • Spanish

    Native or bilingual

Remote only
Primarily works remotely

Experience

  • ArchivoPolitico.com
    FullStack developer
    PRIVATE EQUITY
    February 2026 - May 2026 (3 months)
    Barcelona, Spain
    Built end-to-end a public web platform that archives, indexes and analyzes the Twitter/X activity of 50+ Argentine political figures (~200K tweets dating back to 2010)
    • Data pipeline: Python + Selenium scrapers with incremental updates, deduplication and resume-on-failure; a daily bash pipeline rebuilds the entire site (data, stats, pages, sitemap) unattended.
    • AI editorial layer: automated daily and weekly news-style summaries generated with the Claude API (multi-stage LLM pipeline with per-model cost optimization), injected into the site as publish-ready editorial content.
    • Interaction graph: interactive network map (vis-network) showing who replies to / quotes whom, with drill-down to the actual crossed tweets between any two politicians.
    • Zero-backend frontend: vanilla JavaScript SPA + statically generated pages; client-side full-text search over a custom lightweight index (~5 MB serving a 300+ MB archive); responsive, dark/light theming.
    • SEO & growth: per-politician static pages, structured data (JSON-LD), sitemaps, Google Analytics/AdSense integration.

    Technologies: Python, Selenium, JavaScript, HTML/CSS, Tailwind CSS, vis-network, Chart.js, Claude API / LLM prompt pipelines, Bash, Git, GitHub Pages.
    Selenium LLM Python Claude API TailwindCSS
  • Leading global health and IoT diagnostics platform
    Senior Software Engineer
    MEDICAL
    December 2023 - Today (2 years and 7 months)
    Barcelona, Spain
    Key contributor to a cloud-connected IoT health diagnostics platform, developing full-stack features, data ingestion pipelines, and device interoperability solutions.
    • IoT Database Migration: Executed the seamless migration of local databases across 6,000+ IoT devices with zero data loss. Performance
    • Optimization: Enhanced connectivity between the IoT application and diagnostic devices, reducing average clinical result turnaround time by ~30%.
    • End-to-End Engineering: Developed a critical medical-results printing feature from scratch using React/TypeScript, CUPS, and the IPP protocol, receiving high praise from veterinary clinics.
    • Data Architecture: Designed event-driven ingestion pipelines using Apache Kafka, ensuring high data consistency across HUB, PIMS, ZDX, and Imagyst ecosystems.
    • Cost & Quality Leadership: Optimized Azure Application Insights to significantly reduce infrastructure costs, and introduced mutation testing and clean-code practices adopted team-wide.
    Java Spring boot Apache Kafka IoT React.js
  • Tonai.app
    AI Intonation CoachFounder Founder & Lead Developer
    TECH
    January 2024 - April 2026 (2 years and 3 months)
    Barcelona, Spain
    Designed, built, and launched a cross-platform music practice companion providing real-time audio analysis (intonation, vibrato, dynamics) for string, wind, and vocal musicians. Available on iOS and Android.
    Full-Product Ownership: Formulated and executed the entire product lifecycle solo, from UI/UX design to cross-platform deployment (React Native) and App Store/Google Play release.

    • On-Device Audio Processing: Architected a high-performance, on-device pitch-analysis engine to deliver latency-free visual feedback to users.
    • AI Integration: Implemented an LLM-powered coaching feature using the Anthropic Claude API to automatically synthesize session data into personalized practice plans.
    • Global Scalability & Features: Shipped core modules including progress tracking, an advanced tuner, and a drift-free metronome; fully localized across 10 languages to support an international user base.
    • App Store • Google Play
    Android iOS React Native LLM Artificial Intelligence (AI)
Check out Emiliano's experience

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Education

  • B.Sc. in Software Engineering
    University of Palermo
    2023
  • Professional Frontend Developer
    UTN — Universidad Tecnológica Nacional
    2020
    Professional Frontend Developer
Check out Emiliano's education

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