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Giacomo Guiulfo Knell
Verified Expert in Engineering
Software Developer
Tokyo
Toptal member since June 5, 2025
Bio
Giacomo is a senior full-stack engineer with 8+ years of experience delivering industry-grade software. A versatile generalist, he has built solutions ranging from hybrid web applications to cloud-native infrastructure. Giacomo has contributed to early-stage startups, mid-sized firms, and global enterprises, consistently ensuring reliability, performance, and business value.
Portfolio
Tektome
Ruby on Rails (RoR), Hotwire, Stimulus, PostgreSQL, DevOps, Azure, Redis...
Twitch Interactive
Amazon Web Services (AWS), Go, Grafana, Elasticsearch, REST APIs, DevOps...
AMI
Ruby on Rails (RoR), Ruby, React, Swift, Android Studio, Java, Xcode, iOS...
Experience
- JavaScript - 8 years
- Ruby - 8 years
- Ruby on Rails (RoR) - 8 years
- Go - 8 years
- Amazon Web Services (AWS) - 5 years
- Kubernetes - 4 years
- React - 3 years
- Python - 2 years
Preferred Environment
Ruby, Kubernetes, Go, JavaScript, Stimulus, Hotwire, PostgreSQL, Tailwind CSS, Amazon Web Services (AWS), Ruby on Rails (RoR)
The most amazing...
...project I've worked on is a global-scale video distribution system used by millions of users every day.
Work Experience
Senior Software Engineer
2024 - PRESENT
Tektome
- Designed and built a robust external API, enabling third-party integrations and empowering customers to develop custom applications on top of our platform.
- Integrated a modular workflow engine to power advanced attribute extraction, unlocking scalable automation and custom processing pipelines.
- Optimized critical application paths for 10–20× performance gains, ensuring seamless scalability to meet the demands of Japan’s largest AEC enterprises.
Technologies: Ruby on Rails (RoR), Hotwire, Stimulus, PostgreSQL, DevOps, Azure, Redis, REST APIs, API Integration, Back-end, Back-end APIs, Web Development, JavaScript, APIs, Full-stack Development, Vue, REST, Full-stack, Artificial Intelligence (AI), Git, TypeScript, CSS, HTML, Elasticsearch, SQL, Ruby on Rails 5, CI/CD Pipelines, Security, Terraform
Software Engineer
2022 - 2024
Twitch Interactive
- Developed and maintained back-end services powering the CDNs of both Twitch and Amazon IVS.
- Led the migration of infrastructure from Terraform to CDK, identifying and executing cost-saving strategies that reduced annual expenses by over six figures.
- Resolved live issues impacting a global fleet of thousands of bare-metal nodes delivering hundreds of gigabits per second of video.
Technologies: Amazon Web Services (AWS), Go, Grafana, Elasticsearch, REST APIs, DevOps, API Integration, Back-end, Back-end APIs, Web Development, JavaScript, APIs, Full-stack Development, REST, Full-stack, Artificial Intelligence (AI), Git, TypeScript, HTML, SQL, CI/CD Pipelines, Security, Terraform
Senior Software Engineer
2021 - 2022
AMI
- Served as a full-stack developer at a startup specializing in web and mobile applications that facilitate affiliate relationships between brands and influencers.
- Guided technology adoption decisions, mentored junior engineers, and conducted technical interviews.
- Implemented internationalization across web and mobile platforms, enabling the onboarding of thousands of customers in new markets.
- Led the development of the corporate CRM product, introducing features like commission calculation and compensation distribution.
- Developed key features for the mobile and desktop consumer app, including SAML authentication, passwordless login, and KPI dashboards.
- Improved application-wide search functionality by integrating Elasticsearch, significantly enhancing speed and user experience.
Technologies: Ruby on Rails (RoR), Ruby, React, Swift, Android Studio, Java, Xcode, iOS, Amazon Web Services (AWS), REST APIs, DevOps, API Integration, Back-end, Back-end APIs, Web Development, JavaScript, APIs, Full-stack Development, REST, Full-stack, Git, TypeScript, CSS, PostgreSQL, HTML, Elasticsearch, SQL, Stripe, Stripe API, Ruby on Rails 5, Webpack, Recoil, CI/CD Pipelines, Security
Software Engineer
2020 - 2021
Google Cloud
- Developed Kubernetes controllers in Go to manage the lifecycle of Google Kubernetes Engine (GKE) clusters on Anthos, automating deployment, scaling, and maintenance processes.
- Contributed to the development of cluster administration tools, improving usability and functionality.
- Participated in cross-team technical discussions and contributed to the design and architecture of the Anthos platform.
Technologies: Go, Kubernetes, Google Cloud, REST APIs, DevOps, API Integration, Back-end, Google Cloud Platform (GCP), Back-end APIs, Web Development, JavaScript, APIs, Full-stack Development, REST, Full-stack, Git, HTML, SQL, Material UI, CI/CD Pipelines, Security
Software Engineer
2019 - 2021
Apple
- Served as a full-stack developer focused on creating tools and services to automate infrastructure management for Apple Maps.
- Maintained a web application that empowered site reliability engineers to monitor, perform maintenance, and deploy artifacts to a fleet of bare-metal hosts across multiple data centers.
- Enabled multiple teams across the organization to adopt Kubernetes by developing tools for GitOps-driven deployments.
- Developed an automated dependency update system integrated into hundreds of repositories, generating hundreds of thousands of pull requests for package updates, thereby enhancing security and accelerating deployment frequency.
- Created a company-wide gamification platform for bug-filling competitions, adopted by thousands of employees across the iOS, macOS, and watchOS teams, fostering collaboration and improving software quality.
Technologies: Ruby on Rails (RoR), Ruby, Go, Kubernetes, JavaScript, REST APIs, DevOps, API Integration, Back-end, Back-end APIs, Web Development, APIs, Full-stack Development, REST, Full-stack, Git, TypeScript, CSS, PostgreSQL, HTML, SQL, Ruby on Rails 5, Webpack, Material UI, CI/CD Pipelines, Security, Node.js, Argo CD
Software Developer
2018 - 2019
Scality
- Served as an infrastructure-focused engineer on the team developing Zenko, an open-source platform that enables unified data management across multiple cloud providers through a single API.
- Contributed to the release of the first major version of Zenko by packaging it for Kubernetes and empowering developers to run this system, comprising nearly a dozen services, on any major cloud or even their laptop within minutes.
- Architected and implemented a system to integrate data from NAS storage devices with Zenko, facilitating enterprise customers with a solution to seamlessly migrate hundreds of terabytes of data to the cloud.
Technologies: Python, Node.js, React, Terraform, Ansible, OpenStack, Amazon Web Services (AWS), Google Cloud, Azure, REST APIs, DevOps, API Integration, Back-end, Google Cloud Platform (GCP), Back-end APIs, Web Development, JavaScript, APIs, Full-stack Development, REST, Full-stack, Git, HTML, MongoDB, SQL, Webpack, Redux, CI/CD Pipelines, Security
Experience
Zenko
https://github.com/scality/ZenkoI served as an infrastructure-focused engineer on the team developing Zenko, an open-source multi-cloud storage service. Zenko provides a unified namespace, access API, and search capabilities for data stored locally or in public cloud storage services like Amazon S3 (AWS S3), Azure Blob Storage, or Google Cloud Storage.
Certifications
DECEMBER 2023 - PRESENT
Advanced Developer
42
Skills
Libraries/APIs
Node.js, React, REST APIs, Back-end APIs, Stripe, Stripe API, Vue
Tools
Git, Hotwire, Grafana, Android Studio, Xcode, Terraform, Ansible, Webpack, AWS Cloud Development Kit (CDK)
Languages
Go, Ruby, JavaScript, CSS, HTML, SQL, TypeScript, Python, Swift, Java
Frameworks
Ruby on Rails (RoR), Ruby on Rails 5, Stimulus, Tailwind CSS, Redux, Recoil, Material UI
Paradigms
DevOps, REST
Platforms
Kubernetes, Amazon Web Services (AWS), Azure, iOS, OpenStack, Google Cloud Platform (GCP), AWS IoT
Storage
PostgreSQL, Elasticsearch, Google Cloud, Redis, MongoDB
Other
API Integration, Back-end, Web Development, APIs, Full-stack Development, Full-stack, CI/CD Pipelines, Security, Argo CD, Ruby on Rails 8, Software Engineering, Artificial Intelligence (AI)
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