Sérgio Fonseca
CTO at Oxpay
São Paulo, Brazil
Summary
👤
Senior🎓
Top SchoolSérgio Fonseca is a technology leader and CTO based in São Paulo with over a decade of hands-on programming experience and nine years of professional work in payments and fintech. He began coding at 13 and has deep expertise in C#/.NET, C/C++, Golang and Python, complemented by strong backend architecture skills—SOLID, clean code, microservices, SQL, Redis and Docker. His career spans game development to embedded payment systems and large-scale payment platforms, including senior engineering at Cappta and developer roles at Stone Pagamentos. Known for blending low-level systems thinking with pragmatic product delivery, he also brings security and observability experience (Splunk, CI, REST). A native Portuguese speaker fluent in English, he combines early passion for coding with proven leadership in building reliable payment infrastructure.
9 years of coding experience
11 years of employment as a software developer
Instituto Infnet
Github Skills (72)
easyhook9
csharp9
dotnet8
dll-injection8
markdown7
javascript7
api7
java7
nodejs7
parsing7
windows-service7
golang6
visual-studio6
interpreter6
sql6
Programming languages (8)
Github contributions (5)
Cappta/GoHttpsClientForCSharp
Nov 2017 - Jun 2021
Wrapper for GoHttpsClient in CSharp .NET
Contributions:13 commits, 4 PRs, 6 pushes in 3 years 7 months
dotnetcsharpnet-framework
Cappta/GoHttpsClientDll
Nov 2017 - Jan 2019
Golang's HTTPS client wrapper as DLL compatible with windows XP
Contributions:6 commits, 3 PRs, 1 push in 1 year 2 months
golangclient-wrapperwindows-xplibcurlwindows
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