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Cesar Sampaio
Verified Expert in Engineering
Software Engineer and Developer
Cuiabá - State of Mato Grosso, Brazil
Toptal member since May 9, 2025
Bio
Cesar is an experienced software engineer specializing in developing and maintaining Node.js/Go applications. He integrates advanced 3rd-party services and manages large-scale data with PostgreSQL. He focuses on delivering robust, well-architected software solutions within challenging timelines, while actively participating in code reviews and design optimizations.
Portfolio
Sellfire
TypeScript, Go, Kubernetes, Models, OpenAI, Twilio, PostgREST, Amazon Kinesis...
Genius Yield
Go, TypeScript, Node.js, Postman, PostgREST, Web3, Blockchain, Ethereum...
Disney Streaming Services
Go, Python, Artificial Intelligence (AI), Models, Amazon Kinesis...
Experience
- TypeScript - 5 years
- Python - 5 years
- PostgREST - 5 years
- React - 5 years
- Go - 5 years
- Node.js - 5 years
- Artificial Intelligence (AI) - 5 years
- OpenAI - 3 years
Preferred Environment
Go, Node.js, Python, Ruby, PostgreSQL
The most amazing...
...solution I've created is a large-scale real-time stock prices dashboard with on-demand scaling.
Work Experience
Senior Software Engineer
2022 - PRESENT
Sellfire
- Designed, developed, and maintained scalable Node.js microservices for Sellfire, integrating AI and 3rd-party APIs including Twilio, Salesforce, OpenAI, Google, and Zoom.
- Led initiatives using GraphQL (Apollo Server) and REST APIs to support AI-driven features, improving system maintainability, performance, and data flow.
- Deployed and monitored cloud-native applications on AWS (EC2, S3, Lambda, RDS) with infrastructure-as-code (IaC) principles.
- Collaborated cross-functionally with front-end developers, QA experts, and product managers in Agile and Scrum environments to ensure high-quality deliverables.
- Participated in peer code reviews and AI architecture discussions, advocating for clean architecture, test automation, and scalable model integrations.
- Experienced in building production AI systems with OpenAI, Anthropic, and Hugging Face, including LLM workflows, custom model training, vector databases, RAG pipelines, and TTS integrations optimized for scale.
Technologies: TypeScript, Go, Kubernetes, Models, OpenAI, Twilio, PostgREST, Amazon Kinesis, Redis, Rust, React, Agile, Scrum, Apollo Server, GraphQL, Event-driven Architecture, NATS, Amazon Web Services (AWS)
Senior Software Engineer
2022 - 2022
Genius Yield
- Built and deployed decentralized microservices in a Web3 and blockchain environment, integrating smart contract interactions using the Node.js, Ethereum, and Cardano APIs.
- Developed RESTful APIs and high-throughput back-end services using Fastify, TypeScript, and Docker.
- Applied domain-driven design (DDD) and optimized PostgreSQL queries for performance and data consistency.
- Contributed to front-end development using React, enhancing user experience for blockchain dashboards and token exchanges.
- Participated actively in sprint planning and architecture reviews in a fully remote team.
Technologies: Go, TypeScript, Node.js, Postman, PostgREST, Web3, Blockchain, Ethereum, Cardano, Fastify, Docker, Domain-driven Design (DDD), PostgreSQL, React, Event-driven Architecture, NATS, Kubernetes
Senior Back-end Engineer
2019 - 2021
Disney Streaming Services
- Designed and implemented robust Go services to process large-scale streaming data with Amazon Kinesis and Redis, reducing latency and improving throughput.
- Advocated for and implemented test-driven development (TDD), improving code reliability and the onboarding experience for new developers.
- Created scalable and fault-tolerant solutions within a distributed system using microservices and clean code principles.
- Led documentation efforts and mentored junior engineers on best practices for API design, logging, and monitoring.
Technologies: Go, Python, Artificial Intelligence (AI), Models, Amazon Kinesis, Test-driven Development (TDD), Event-driven Architecture, NATS, Kubernetes, Amazon Web Services (AWS)
Software Engineer
2019 - 2021
Tc
- Built a real-time stock market broadcasting platform leveraging Go, NATS, and GraphQL, designed for low-latency and high-throughput event processing.
- Designed horizontally scalable services using Google Cloud Platform (GCP), AWS, and Docker, deployed via CI/CD pipelines.
- Created custom metrics pipelines with InfluxDB, Elasticsearch, and Redis to monitor trading volume and anomalies.
- Partnered with data vendors and product stakeholders to ensure regulatory compliance and real-time accuracy.
Technologies: Node.js, Go, GraphQL, Google Cloud Platform (GCP), Amazon Web Services (AWS), Docker, InfluxDB, Elasticsearch, Redis, Event-driven Architecture, NATS, Kubernetes
Experience
DonorsRank
https://donorsrank.com/The DonorsRank platform is dedicated to recognizing and celebrating those who are making a difference, whether they choose to do so privately or publicly. Our mission was to provide a transparent and trustworthy platform for charitable giving, where donors could choose how they wanted their impact to be recognized. Whether they preferred to keep their generosity private or take pride in being recognized in a ranking of impactful donors, DonorsRank supports every donor's choice.
AI-enhanced Lead Routing Engine
AI-driven lead routing platform: TypeScript/Node.js platform with real-time telephony integrations, AI-generated insights, advanced lead routing logic, and PostgreSQL + Prisma architecture. Designed end-to-end to support high-scale sales operations.
Education
2016 - 2021
Bachelor of Engineering Degree in Mathematics and Computer Science
Federal University of Mato Grosso (UFMT) - Cuiaba, Brazil
Skills
Libraries/APIs
Node.js, PostgREST, React
Tools
Postman
Languages
Go, TypeScript, Python, Ruby, Rust, GraphQL
Paradigms
Event-driven Architecture, Agile, Scrum, Test-driven Development (TDD)
Platforms
Kubernetes, Amazon Web Services (AWS), Twilio, Blockchain, Ethereum, Cardano, Docker, Google Cloud Platform (GCP)
Frameworks
Fastify
Storage
Redis, PostgreSQL, InfluxDB, Elasticsearch
Other
Artificial Intelligence (AI), Models, NATS, Machine Learning, Amazon Kinesis, OpenAI, Mathematics, Computer Science, Apollo Server, Web3, Domain-driven Design (DDD)
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