Massimo Cairo, Developer in Vilnius, Vilnius County, Lithuania
Massimo is available for hire
Hire Massimo

Massimo Cairo

Verified Expert  in Engineering

Full-stack Web Developer

Vilnius, Vilnius County, Lithuania
Toptal Member Since
November 22, 2021

Massimo wrote the first line of code at seven and won the first medal in an international programming competition at 16. He is currently a full-stack and web developer most fluent in React, although he has worked with a wide range of technologies in the past. He loves solving complex problems and, at the age of 30, he already has 20+ publications in algorithms and theoretical computer science. Massimo is also the founder and sole developer of, a study tool for students.


(a multinational Telco group)
React, OpenAI, OpenAI GPT-3 API, OpenAI GPT-4 API, Tailwind CSS, Cloud...
Artificial Intelligence (AI), PyTorch...
TypeScript, React, Web, HTML5, Stripe, PWA, Progressive Web Applications (PWA)...




Preferred Environment

Linux, Visual Studio Code (VS Code), React, TypeScript, Git, GitHub, JavaScript

The most amazing...

...project I've developed is, a web-based app that lets students learn faster by adding and practicing questions directly on PDF notes.

Work Experience


2023 - PRESENT
(a multinational Telco group)
  • Designed and developed an AI-assisted editor, based on GPT-4 with vision capabilities, to be used internally to prepare requirement documents related to tagging of website pages and app screens (MarTech).
  • Integrated the OpenAI API with the back end, with support for streaming generated responses to the client and converting them into a structured format on the fly.
  • Created a data pipeline to generate effective prompts using semi-structured internal company documents, free text prompts, and fully-structured editor data.
  • Implemented a front end using React, Chakra UI, and Firebase SDK.
Technologies: React, OpenAI, OpenAI GPT-3 API, OpenAI GPT-4 API, Tailwind CSS, Cloud, API Integration, Large Language Models (LLMs), GPT, Chatbots, ChatGPT

AI Researcher

2023 - PRESENT
  • Created a generative AI for fonts from scratch, based on the Transformers architecture, using PyTorch.
  • Developed the data transformation pipeline required to train the model efficiently on existing font files.
  • Set up the infrastructure to train the model in cloud, using GCP's Vertex AI custom training jobs.
Technologies: Artificial Intelligence (AI), PyTorch, Generative Pre-trained Transformers (GPT), Google Cloud Platform (GCP), Python, Cloud, Rust, Large Language Models (LLMs), GPT, Chatbots, ChatGPT

Founder and Full-stack Web Developer

2020 - PRESENT
  • Solely designed, developed, and published a web-based app that allows students to add and practice questions on PDF files. The app is production-ready, scalable, mobile-ready, cloud-synchronized, and offline-ready.
  • Implemented a pixel-perfect web-based UI with mobile-native look-and-feel, responsive layouts, custom-tailored components and animations, drag-and-drop integration, high performance and PWA support.
  • Mastered advanced HTML5, CSS3, and modern web APIs such as Service Workers, IndexedDB, Canvas elements, Web Workers, Cache API, multi-touch events, drag-and-drop events, DOM manipulation, programmatic animations, History API, and more.
  • Improved the app over time by collecting and analyzing usage data, both as analytics and session recordings. Tracked and optimized acquisition, onboarding conversion rate, activations, and retention rates.
  • Prepared marketing material and marketed the app via video ads and other channels. Set up payments in the app and user-to-user referrals.
Technologies: TypeScript, React, Web, HTML5, Stripe, PWA, Progressive Web Applications (PWA), Stripe Checkout, Architecture, Web Development, Responsive Web Design (RWD), User Experience (UX), Full-stack, CI/CD Pipelines, React Redux, Performance, WebSockets, Amazon Web Services (AWS), Android, Android SDK, iOS, iOS SDK, Web Accessibility, User Interface (UI), SVG Animation, MDX, Jest, Search Engine Optimization (SEO), Front-end, Microservices, Databases, Technical Leadership, Google Cloud Platform (GCP), Google Cloud, CTO, Leadership, ECMAScript (ES6), SVG, Early-stage Startups, Software Architecture, Full-stack Development, Database Design, Next.js, Redux, Data Analytics, PDF, Front-end Development, Back-end Development, Cloud Infrastructure, Project Management, Firebase, Firebase Cloud Messaging (FCM), SaaS, Node.js, UI Components, Design Systems, Chrome Extensions, Technical Architecture, UX Design, Stripe API, Vercel, Prisma, Solution Architecture, Cloud, API Integration, SDKs, SDK Development, Authentication, Monorepos, Startups, Mobile Development, Mobile Apps, B2C

Web Developer

2021 - 2022
  • Developed the main company website from scratch using React and CSS-in-JS, with responsive and custom layouts, starting from the designs provided in Figma.
  • Contributed to the development of the core product of the company, an open-source cryptocurrency wallet living in a web extension, integrating with the team and its processes.
  • Analyzed and fixed bugs in a web (multi-browser) extension. Identified and mitigated performance issues, implemented new screens, refactored and improved the source code quality, and participated in code reviews.
Technologies: React, HTML, JavaScript, CSS, Gatsby, Web Extensions, React Redux, Redux, API Integration, Web3, Blockchain, MetaMask

Front-end Developer | Contractor

2020 - 2020
  • Developed a web-based PDF viewer with custom functionality using Angular and PDF.js and integrated it into a complex web application.
  • Contributed to designing a custom blockchain implementation similar in functionality to Amazon Quantum Ledger Database (QLDB).
  • Optimized the web-based PDF viewer's performance on large PDFs by using browser profiling tools and reducing the Angular-related overhead.
  • Collaborated with a team of around ten people, following their best practices regarding agile development, code quality, and code reviews.
Technologies: Angular, Web, REST, REST APIs, Web Development, Responsive Web Design (RWD), User Interface (UI), User Experience (UX), CI/CD Pipelines, Automated Testing, Performance, Cypress, Front-end, AngularJS, Microservices, ECMAScript (ES6), PDF, Front-end Development, Node.js, UI Components, Solution Architecture, API Integration, Technical Writing, Blockchain

Machine Learning Engineer | Data Scientist | Software Engineer

2018 - 2020
BioBeats (Merged into Huma Therapeutics)
  • Developed machine learning-based algorithms to process physiological signals in public datasets, such as ECG signal shape analysis and correlation with other physiological factors.
  • Designed algorithms to process real-time data from smartphone and wearable sensors—for instance, to detect heart and respiration rate from motion sensors—and implemented them as part of mobile apps.
  • Contributed to designing and developing an internal framework for the cross-platform implementation of data-processing algorithms in native Android and iOS apps.
Technologies: TensorFlow, Pandas, React Native, TypeScript, REST, REST APIs, APIs, Architecture, Mobile, CI/CD Pipelines, Performance, Android, Android SDK, iOS, iOS SDK, MySQL, MongoDB, Amazon Web Services (AWS), Microservices, Databases, Google Cloud Platform (GCP), Google Cloud, Data Engineering, ECMAScript (ES6), Machine Learning, Dynamic Programming, Python, Software Architecture, Full-stack Development, Data Architecture, Data Analytics, AI Programming, Back-end Development, Technical Architecture, Cloud, API Integration, SDKs, SDK Development, Technical Writing, Monorepos, Healthcare, Mobile Development, Mobile Apps, B2C, Large Language Models (LLMs)

Chief Back-end Engineer | Co-founder

2012 - 2014
Kiwi S.r.l. (defunct)
  • Designed and developed REST APIs for our mobile apps, which tracked user location and allowed users to share content with other users nearby.
  • Implemented an efficient spatial index for querying user locations on top of a non-spatial cloud database.
  • Managed up to three back-end developers and oversaw the mobile front-end development regarding their integration with the back-end APIs.
Technologies: Java, Google App Engine, REST, REST APIs, Location Tracking, APIs, Architecture, Full-stack, CI/CD Pipelines, Databases, Technical Leadership, Google Cloud Platform (GCP), Google Cloud, CTO, Leadership, Test-driven Development (TDD), Early-stage Startups, Software Architecture, Full-stack Development, Database Design, Data Analytics, Back-end Development, Cloud Infrastructure, Project Management, Technical Architecture, PostgreSQL, Solution Architecture, Cloud, Mobile Development, Mobile Apps, B2C

A web-based app that allows students to add and practice questions on PDF notes.

I designed, developed, and published the app unassisted, including UI/UX design, copywriting, responsive front-end UI implementation, and offline-ready cloud synchronization.

International Olympiad in Informatics | Awards and Current National Committee Membership
The International Olympiad in Informatics (IOI) is the world's most prestigious computer science competition toward secondary school students sponsored by UNESCO and IFIP.

In 2007, I was the youngest participant and the youngest first-place winner ever of the Italian national olympiad. I won national first place two more times and made it to the national team four times, winning three international silver and one bronze medal.

I am currently a member of the Italian technical and scientific committee, contributing to designing and implementing problems for the national edition and selecting the national team.


TypeScript, CSS, JavaScript, HTML, ECMAScript (ES6), Python, HTML5, SQL, GraphQL, Java, Python 3, MDX, Rust, WASM, C++, C


Next.js, Android SDK, React Native, Angular, iOS SDK, Jest, AngularJS, Express.js, Cypress, Redux, Tailwind CSS


React, Node.js, REST APIs, Stripe API, TensorFlow, Pandas, Stripe, React Redux, PyTorch


Responsive Web Design (RWD), Dynamic Programming, Database Design, B2C, REST, Automated Testing, Microservices, Test-driven Development (TDD), Linear Programming, Mobile Development, Search Engine Optimization (SEO), UX Design


Web, Firebase, Android, Google Cloud Platform (GCP), Mobile, iOS, Vercel, Visual Studio Code (VS Code), Docker, Google App Engine, Amazon Web Services (AWS), Blockchain


Google Cloud, Cloud Firestore, Databases, PostgreSQL, MySQL, MongoDB


Algorithms, Competitive Programming, APIs, Architecture, Web Development, Full-stack, Performance, Front-end, Technical Leadership, CTO, Machine Learning, Optimization, Early-stage Startups, Software Architecture, Full-stack Development, AI Programming, PDF, Front-end Development, Back-end Development, SaaS, UI Components, Technical Architecture, Solution Architecture, Cloud, API Integration, SDKs, SDK Development, Startups, Chatbots, Back-end, Apollo Server, Programming Language Design, User Interface (UI), SVG Animation, Data Engineering, Leadership, Programming Languages, SVG, Data Architecture, Search Algorithm Design, Data Analytics, Cloud Infrastructure, Design Systems, Authentication, Technical Writing, WebAssembly, Mobile Apps, Large Language Models (LLMs), GPT, ChatGPT, Complexity Theory, Location Tracking, Mathematics, Data Structures, PWA, Progressive Web Applications (PWA), User Experience (UX), CI/CD Pipelines, WebSockets, Web Accessibility, Chrome Extensions, Gatsby, Web Extensions, Artificial Intelligence (AI), Generative Pre-trained Transformers (GPT), OpenAI, OpenAI GPT-3 API, OpenAI GPT-4 API, Web3, Monorepos, Poker


React Apollo, Firebase Cloud Messaging (FCM), Sequelize, Stripe Checkout, Git, GitHub, Prisma, MetaMask

Industry Expertise

Project Management, Healthcare

2015 - 2019

PhD in Mathematics

University of Trento - Trento, Italy

2013 - 2015

Master's Degree in Computer Science

University of Pisa - Pisa, Italy

2010 - 2015

Complementary Masters' Diploma in Mathematics and Computer Science (Full Scholarship)

Scuola Normale Superiore - Pisa, Italy

2010 - 2013

Bachelor's Degree in Computer Science

University of Pisa - Pisa, Italy

Collaboration That Works

How to Work with Toptal

Toptal matches you directly with global industry experts from our network in hours—not weeks or months.


Share your needs

Discuss your requirements and refine your scope in a call with a Toptal domain expert.

Choose your talent

Get a short list of expertly matched talent within 24 hours to review, interview, and choose from.

Start your risk-free talent trial

Work with your chosen talent on a trial basis for up to two weeks. Pay only if you decide to hire them.

Top talent is in high demand.

Start hiring