Carlo Ferraris
Principal Engineer at Mercari, Inc.
Tokyo, Japan
Summary
👤
Senior🎓
Top SchoolCarlo Ferraris is a Principal Engineer based in Tokyo with 15 years of experience building and scaling backend systems for large e-commerce and cloud platforms. At Mercari he leads an AI Enablement team and previously architected the backend that serves hundreds of engineers, designing hundreds of services and driving optimizations that saved the company millions annually. He blends deep systems knowledge (Kubernetes, GCP, Terraform, MySQL/Spanner, Go) with hands-on AI work (LLMs, RAG, agents) to make internal developer tooling safe, scalable, and fast. A pragmatic leader and mentor, he has scaled teams and created organizational guidelines that improved production readiness and operational efficiency. Carlo is also an active open-source contributor to Go ecosystem projects—improving performance in golang/go and optimizing the easyjson serializer—demonstrating a focus on low-level efficiency and real-world impact. His background in telecommunications and machine learning informs a multidisciplinary approach to building resilient, cost-effective infrastructure.
15 years of coding experience
11 years of employment as a software developer
Machine Learning, Data Mining, Delay-Tolerant Networking, Machine Learning, Data Mining, Delay-Tolerant Networking at Teknillinen korkeakoulu-Tekniska högskolanLiceo Scientifico Statale Piero Gobetti, TorinoTelecommunication Engineering (M.Sc), Telecommunications, Information Technology, Computer Science, Telecommunication Engineering (M.Sc), Telecommunications, Information Technology, Computer Science at Politecnico di Torino
English, Italian, French, German, Japanese
Stackoverflow
29,106reputation
2.7mreached
200answers
31questions
mysql
top-5%
llvm
top-5%
javascript
top-1%
Github Skills (24)
javascript10
testing10
go10
performance-optimization10
concurrency10
json-serialization10
mysql9
llvm9
buffering9
buffer9
code-generation9
data-structures8
data-structure8
algorithms8
json8
Programming languages (24)
Github contributions (5)
mailru/easyjson
Feb 2020 - Apr 2020
Fast JSON serializer for golang.
Role in this project:
Back-end Developer
Back-end DeveloperContributions:6 commits, 6 PRs, 11 comments in 1 month
Contributions summary:Carlo primarily contributed to optimizing the `easyjson` library, a JSON serialization tool for Go. Their work focused on enhancing performance through techniques like inlining and by using `net.Buffers` for efficient data writing. They also implemented features such as optional string interning and refactored code for better efficiency. These changes, demonstrated through code modifications and test additions, indicate a focus on performance and code quality within the project.
golangjson-serializationcode-generationjsonpathperfomance
golang/go
Jul 2022 - Sep 2022
The Go programming language
Role in this project:Back-end Developer
Back-end DeveloperContributions:2 reviews, 2 commits, 5 PRs in 1 month
Contributions summary:Carlo primarily contributed to performance optimizations and refactoring within the Go programming language. Their work focused on improving the efficiency of core functionalities, particularly within the `bytes` and `sync` packages. Key changes included enhancing `bytes.Buffer` for cache-friendliness, improving the performance of `sync.Mutex`, `sync.Once`, and `sync.RWMutex` fast paths. The user also made changes to `math/rand` for thread safety and optimization.
golanggopluscompilerprogramming-languageinterpreter
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