Hi, I'm Javier Machín.
Senior Software Engineer.

Currently working for the proptech Ukio, a company that specializes in offering fully furnished, design-forward apartments for monthly stays through a digitized customer experience.

Key Contributions & Impact:

• Spearheaded the migration of legacy features to a new, high-performance application, directly boosting PageSpeed scores by over 20%.
• Architected cost-saving optimizations for Vercel and Sanity CMS by leveraging CDNs and improving queries, slashing hosting costs by more than 50%.
• Engineered the company's primary mobile app from ideation to launch, managing the entire process including implementation in React Native and publishing to the Apple and Google Play Stores.

Tech Stack: React, React Native, TypeScript, Next.js, Zod (data validation), Zustand (state management), Sanity CMS, Tailwind, Vercel, AWS (Elastic Beanstalk).

I was directly involved in the creation of the B2B side of the German unicorn Grover. With over $2.2B raised, Grover makes technology accessible to everyone by enabling them to subscribe to tech products monthly. I worked on the B2B front-end, architecting and implementing features to drive business growth.

Key Contributions & Impact:

• Enhanced the B2B user registration flow, implementing UX improvements and A/B testing which increased the conversion rate by 20%.
• Championed and integrated Cypress end-to-end testing into the team's CI/CD pipeline, significantly reducing the number of bugs reaching production.
• Mentored and onboarded new engineers through a buddy program, improving team cohesion and ramp-up speed while maintaining all development responsibilities.

Tech Stack: TypeScript, Next.js, React, GraphQL, Cloudfront (Micro-frontend routing), Cypress.

Worked on the development of the successful digital learning platform Insendi, which provides universities such as Imperial College London, ESMT Berlin, University of Melbourne, Johns Hopkins Carey Business School, and HKUST the ability to create engaging online courses. Insendi was acquired by StudyGroup in 2020. My role was to build interactive learning activities and enhance the user experience for both students and educators.

Key Contributions & Impact:

• Proactively improved platform stability by addressing client pain points and shipping targeted code fixes, which significantly reduced live support requests and operational costs.
• Acted as a technical subject-matter expert (SME) alongside the CTO in key client meetings at Imperial College London, helping secure and strengthen university partnerships.
• Led the migration of legacy learning activities to a modern and more performant Next.js application, enhancing reliability and the end-user experience.

Tech Stack: React, Redux, Next.js, JavaScript, Enzyme.

Maintained and added new features to the music distribution application Beatroot, part of the Tennessee-based music corporation Made in Memphis, founded by Hall of Fame musician David Porter. My work involved improving front-end performance and leading the effort to develop and implement a new, modern UI for the platform.

Key Contributions & Impact:

• Developed a key monetization feature enabling the creation of song clips for social media platforms like TikTok, opening up new revenue streams for artists.
• Engineered a new multi-part file upload system with pause/resume functionality, slashing asset upload times by 40% and dramatically improving the user experience for music distributors.
• Led the complete redesign and development of the application's UI using React and Redux, achieving 95% test coverage and significantly reducing application crashes.

Tech Stack: React, Redux, TypeScript, JavaScript, Ruby on Rails.

Through the Swedish agency Odd Camp, I provided consulting and development services for multiple high-profile clients, building bespoke web products tailored to their unique needs. Clients Included: Paradox Interactive, Naturkartan, and Blendow Lexnova.

Key Contributions & Impact:

• Designed and built a promotional WebGL and VR-compatible game for the launch of 'Wraith: The Oblivion - Afterlife,' which received multiple industry accolades.
• Executed the front-end implementation for the 2021 redesign of the official website for the multi-million selling game 'Cities: Skylines.'
• Drove a 30% reduction in client hosting costs by architecting and implementing more efficient technology stacks, boosting both performance and developer productivity.

Tech Stack: React, Next.js, TypeScript, JavaScript, Ruby on Rails, Gatsby (static site generation), A-Frame (WebGL and VR framework).

An AI-powered web app that generates illustrated stories from a user's free-text description.

This project was a practical exercise in bridging the gap between AI concepts and real-world application, demonstrating my ability to build and deploy a novel service that would not be possible without the combination of advanced AI use and traditional software engineering. The final product is a secure and operationally cost-effective solution.

Key Features & Technical Accomplishments:

• Created a secure, public-facing service that leverages a LLM for three distinct tasks: parsing user input, generating the story's narrative, and crafting the prompts for the image generation API. This approach strikes a balance between creative freedom and content moderation to prevent inappropriate stories.
• Architected cost-effective solutions using a combination of open-source LLM, open-source image generation model, and optimized API queries, ensuring the application remains highly functional while maintaining low operational costs.
• Developed a robust rate-limiting system for anonymous users, which prevents service abuse and protects against excessive API credit consumption without requiring user sign-ups.
• Engineered a solution to manage the unpredictable nature of AI-generated content. I achieved this by carefully blending prompt engineering, generation parameters, and robust error handling to transform free-text and creative AI outputs into a reliable and structured format.
• Integrated comprehensive analytics to monitor user behavior, gain insights into user engagement, and inform future improvements.
• Implemented a blacklist capability to manage and ban service abusers, protecting the service and its resources.

Try it out: magicaistory.com

Tech Stack: Next.js, TypeScript, LLM / AI Image Generation APIs, React, Tailwind, Vercel, Redis (rate limiting), Supabase (Postgres for blacklist).