Sergi Rizkallah Backend & Data Infrastructure Engineer

Backend-focused software engineer with experience building scalable financial data pipelines and distributed systems. Worked on fraud detection infrastructure processing millions of transactions daily using Scala, Spark, and AWS.

Professional Experience
Software Developer, Nasdaq Verafin
01/2025 – Present | St John's

• Optimized ACH transaction matching algorithms, improving processing performance by 23–27% across ~2k financial institutions

• Built scalable batch ingestion pipelines for RTP/​FedNow transaction systems processing millions of financial records daily

• Developed distributed data processing workflows using Scala, Spark, EMR, S3, Lambda, and SQS

• Designed data lake transformation and export pipelines with Parquet-based workflows and SQL bulk import systems

• Managed cloud infrastructure and deployment workflows using Terraform and AWS services

03/2024 – 12/2024 | St John’s, NL

• Maintained and optimized a web platform for marine and ocean conservation research projects.

06/2022 – 12/2023 | Alex, Egypt
  • •Built and maintained backend systems for fleet management, streaming, and e-commerce platforms serving 16k+ daily active users and 100k+ daily requests
  • •Developed CI/​CD automation pipelines for a low-code/​no-code platform, reducing project setup time by 50%
  • •Reduced shipping costs by 15% through SQL optimization and algorithmic improvements for marketplace logistics workflows
  • •Improved inventory turnover by 20% and increased sales by 10% through automated pricing and discount systems
  • •Integrated Stripe, Tap, and NFC payment systems across multiple production applications
  • •Mentored junior developers and conducted code reviews within a 3-person engineering team
    • Education
    Master of Science in Computer Science, Memorial University of Newfoundland⁠
    01/2024 – 12/2025 | St. John's, NL
    Bachelor of Science in Computer Science, Alexandria University⁠
    08/2018 – 07/2022 | Alex, Egypt
    Skills

    Languages: Scala, Java, TypeScript, Python, SQL

    Backend & Distributed Systems: Spark, EMR, Node.js, NestJS, Spring Boot

    Cloud & Infrastructure: AWS (S3, Lambda, SQS, RDS, ECR), Terraform, Docker, Kubernetes

    Databases: PostgreSQL, MySQL, MongoDB, Redis

    Frontend: React, Next.js

    ML/Data: Pandas, Scikit-learn, PyTorch

    Projects
  • •Built ML models for fraud detection on highly imbalanced financial datasets using Random Forests and Neural Networks
  • •Applied resampling techniques, including oversampling and undersampling, to optimize recall and minimize false negatives
  • •Achieved 97.83% F1-score with optimized neural network models
  • •Tools: Python, Scikit-learn, Pandas, NumPy