Nicolas Sarfati, Developer in Buenos Aires, Argentina
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Nicolas Sarfati

Verified Expert  in Engineering

Software Developer

Buenos Aires, Argentina
Toptal Member Since
May 31, 2022

Nicolas has more than 10 years of experience as a software engineer. Over the last few years, Nicolas has been challenging himself as a technical leader in a few companies, constantly looking for new challenges and willing to learn new stuff. He enjoys solving complicated problems in a clean way and is interested in working on back-end and performance-related projects.


Java, ISO 8583, HSM, Amazon Simple Queue Service (SQS), MySQL, PostgreSQL...
Naranja X
Java, Node.js, Go, GitLab, Datadog, Docker, Kubernetes
Back-end Development, Java, New Relic, Fintech, Datadog, Gradle, GitHub




Preferred Environment

Linux, IntelliJ IDEA, Terminal, iTerm2, MacOS, Sublime Text 3

The most amazing...

...project that I've managed is related to a working payment processor, issuing prepaid cards that work in real life. The project was created in less than a year.

Work Experience

Technical Lead

2021 - PRESENT
  • Managed the team responsible for processing all payments from the prepaid cards issued by Pomelo.
  • Processed more than a million payment transactions.
  • Monitored applications' status with Prometheus, Grafana, and New Relic.
Technologies: Java, ISO 8583, HSM, Amazon Simple Queue Service (SQS), MySQL, PostgreSQL, Mastercard

Technical Lead

2020 - 2021
Naranja X
  • Ran a multidisciplinary team composed of iOS, Android, and back end.
  • Managed the team that developed the second-factor authentication module, which was used on critical flows in the entire Android and iOS application.
  • Headed the team owner of money transfer flow, who adapted and restyled the flow to be compliant with the Argentinian Central Bank's (BCRA) guidelines and improved the end product.
Technologies: Java, Node.js, Go, GitLab, Datadog, Docker, Kubernetes

Senior Software Engineer

2019 - 2020
  • Redesigned the entire back-end architecture to be resilient to all the possible failures and prepared for new coming features.
  • Reduced the response time of the back-end services by 50%.
  • Reduced the error rate by 10% in the back-end services. It turned into more resilient handling failures from external services.
  • Coached new team members and managed the team's roadmaps.
Technologies: Back-end Development, Java, New Relic, Fintech, Datadog, Gradle, GitHub

Senior Software Engineer

2018 - 2019
OLX Global
  • Developed and maintained multiple back-end user-related services that allowed the entire user lifecycle, registrations, editions, deletions, and logins.
  • Built a highly scalable service that allowed buyers from the platform to rate the buying experience.
  • Used Java, Python, and Spark in all microservices and Prometheus and New Relic for metrics monitoring.
Technologies: Java, Amazon RDS, Redis, Red Hat OpenShift, GitLab, New Relic, Prometheus

Senior Software Engineer

2016 - 2018
Naspers Limited
  • Developed a big data service with Python and Spark that converted not normalized data into synthesized one based on different business logic.
  • Allowed to answer exciting questions about any platform users.
  • Processed more than 20 gigabytes of raw data per day.
  • Tracked application status with Prometheus, Grafana, and New Relic.
Technologies: Python, Spark, Amazon Elastic MapReduce (EMR), Amazon Simple Queue Service (SQS)

Senior Software Engineer

2011 - 2016
  • Developed a scheduler service capable of handling a vast amount of asynchronous tasks. Built the main back-end service capable of sending engagement Push notifications and marketing emails to all OLX platforms.
  • Processed a huge amount of data in Batch and loaded it into an Amazon Redshift database.
  • Handled more than five million events per day without delay.
Technologies: Java, Python, Back-end Development, Amazon Web Services (AWS), HTTP, Jenkins, GitHub, GitLab CI/CD, GitLab, Redis, MySQL, Apache Maven, Redshift

Raspberry Stats Center
A personal project to draw different stats in an ILI9341 screen with a Raspberry.

It was an IoT project to summarize the home internet speed, get the number of ads blocked by the PIHole application, and get a summary of the NAS temperature (QNAP).
2011 - 2022

Master's Degree in Computer Science

University of Buenos Aires - Buenos Aires, Argentina




IntelliJ IDEA, Terminal, Sublime Text 3, Jenkins, GitHub, GitLab CI/CD, GitLab, Apache Maven, Amazon Elastic MapReduce (EMR), Amazon Simple Queue Service (SQS), Gradle, Canvas


Java, SQL, Bash, Python, Go, C




Linux, MacOS, Amazon Web Services (AWS), Red Hat OpenShift, New Relic, Docker, Kubernetes, Raspberry Pi


Redis, MySQL, Redshift, Datadog, PostgreSQL


HTTP, Back-end Development, iTerm2, Performance, Complexity Theory, Amazon RDS, Prometheus, Fintech, ISO 8583, HSM, Mastercard

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