Julien Nahum, Developer in Paris, France
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Julien Nahum

Verified Expert  in Engineering

Full-stack Developer

Paris, France
Toptal Member Since
May 3, 2021

Julien is a full-stack software engineer with over six years of experience building solutions that help solve issues for businesses and people, including a digital restaurant menu solution and a London real-estate listing aggregator. He's also founded and sold PasseTonBillet, a startup that helps people to resell their train tickets. Julien has also worked for Amazon Web Services (AWS), where he improved the performance of S3, the largest storage product in the world.


Amazon Web Services (AWS)
Java, Vue, Amazon Web Services (AWS), Python, Data Science, Data Processing...
Laravel, Marketplaces, Stripe, Amazon Web Services (AWS), Bootstrap, SaaS, Vue...
Freelance Work
Laravel, Vuex, Vue, PostgreSQL, AWS DevOps, Serverless...




Preferred Environment

PyCharm, Slack, MacOS, PhpStorm, iTerm2, PHP, Python, Vue, Amazon Web Services (AWS), Notion

The most amazing...

...piece of software I've developed is a cloud data processing pipeline, capable of ingesting all the logs produced by S3 in the US.

Work Experience

Software Development Engineer

2019 - 2021
Amazon Web Services (AWS)
  • Developed a distributed data processing pipeline to ingest terabytes of logs.
  • Led the development of a tool to trace requests and identify issues in a system developed by more than 500 engineers. The tool can automatically detect regressions and assign them to the responsible team.
  • Created a dashboard that reported issues found by the distributed tracing tool to the leadership. It allows AWS leaders to know what is going on in S3 performance-wise and allows service team engineers to get insights into found issues.
  • Planned the work and roadmap and organized the sprints for the three engineers working on the two above-mentioned projects (tracing tool and dashboard.).
  • Worked six months on a new AWS product (until launch): S3 Object Lambda. Conducted security reviews and worked on DevOps and many other tasks.
Technologies: Java, Vue, Amazon Web Services (AWS), Python, Data Science, Data Processing, JavaScript, CSS3, Tailwind CSS, Bootstrap


2018 - 2020
  • Designed the system, the code, and system architecture; also implemented all the DevOps work on AWS.
  • Created the entire marketplace from scratch using modern web technologies.
  • Scoped missions and managed external workforce (freelancers and agencies).
  • Implemented different growth hacking strategies to grow user base to 30,000 in less than two years.
Technologies: Laravel, Marketplaces, Stripe, Amazon Web Services (AWS), Bootstrap, SaaS, Vue, Marketing, Customer Support

Software Development Engineer

2016 - 2018
Freelance Work
  • Developed an e-learning online platform for pharmacists to learn how to sell vet medicines. The platform is still live today.
  • Built an e-shop for a new jewelry brand (used WordPress and different plugins). Created a custom theme for the brand.
  • Created a mobile app for street sellers of British American Tobacco. The back end was a Laravel application with an administration dashboard.
Technologies: Laravel, Vuex, Vue, PostgreSQL, AWS DevOps, Serverless, Amazon Web Services (AWS), Python, WordPress, jQuery, Ionic, iOS, Android

Web Developer Intern

2015 - 2015
Infront Analytics
  • Participated in the development of the new website (HTML, CSS, JavaScript, and Bootstrap).
  • Worked as a member of a team developing an algo-trading project (Java).
  • Designed advertisement materials (Illustrator, Adobe After Effects, and Final Cut).
Technologies: Integration, JavaScript, CSS, Bootstrap, Java


I was the CTO of PasseTonBillet, a French marketplace for reselling train tickets.

Tasks Accomplished:
• Designed the system and code architecture.
• Created the entire marketplace from scratch using modern web technologies.
• Prepared missions and managed external workforce (contractors and agencies).
• Implemented various growth hacking strategies to grow the user base to 30,000 in less than two years.

I have now sold my shares of the company, and I regularly work on it as an external contractor.


A digital restaurant menu solution that around 50 restaurants use every day. It has been in production for more than a year now.

I worked on this as a side project along with two other developers that I've mentored.


A real estate listing aggregator to help people looking to rent a flat (apartment) in London.

I worked alone on this project (coding, architecture, DevOps, design, and so on) and it was publicly released a few months back. People have already found their dream homes in London thanks to Moovino.


PHP, Python, CSS3, JavaScript, Java, CSS


Laravel, Tailwind CSS, Bootstrap, Ionic


Vue, Vuex, jQuery, Stripe


Amazon Web Services (AWS), MacOS, Web, WordPress, iOS, Android, AWS Lambda


Software Engineering, Full-stack, iTerm2, Algorithms, Machine Learning, Applied Cryptography, Data Mining, Data Processing, SaaS, Reverse Engineering, AWS DevOps, Serverless, Integration, Marketplaces, Customer Support, Scraping, Web Crawlers


Data Science


PyCharm, Slack, PhpStorm, Notion



Industry Expertise


2015 - 2019

Master's Degree in Computer Science

University College London - London, UK