Mario Oprea, Developer in Brașov, Brașov County, Romania
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Mario Oprea

Verified Expert  in Engineering

Amazon API Gateway Developer

Brașov, Brașov County, Romania
Toptal Member Since
November 14, 2018

Mario is an AWS certified developer and solutions architect with two years of experience developing Python Serverless APIs deployed on AWS Lambda and AWS API Gateway. For more than a decade, he's contributed to the development of CMS, eCommerce, and e-learning enterprise platforms built for Fortune 500 companies and successful startups.


Weezy Group Ltd
Ruby on Rails (RoR), PostgreSQL, Heroku, Python, Elasticsearch, Go, AWS Lambda...
Test-driven Development (TDD), Kubernetes, PostgreSQL, Ruby, Looker, BigQuery...
QTeam Software Solutions SRL
System Advisor Model (SAM), AWS CloudFormation, Redshift, Data Pipelines...




Preferred Environment

AWS Lambda, Tmux, Amazon Web Services (AWS), PlantUML, Vim Text Editor, Git, Docker, IntelliJ IDEA

The most amazing...

...project I've architected and built is an enterprise Serverless e-learning platform with SAML, LTI, and Experience API.

Work Experience

Senior Back-end Engineer

2021 - 2021
Weezy Group Ltd
  • Developed and synchronized processes between the inventory management system and the eCommerce marketplace.
  • Pioneered an admin interface to simplify and automate merchandising.
  • Engineered alternative product search based on Elasticsearch.
Technologies: Ruby on Rails (RoR), PostgreSQL, Heroku, Python, Elasticsearch, Go, AWS Lambda, Amazon DynamoDB, AWS Step Functions, Amazon Simple Queue Service (SQS), Okta

Senior Back-end Engineer

2019 - 2021
  • Designed and implemented background processes to initiate, track, and reconcile internal flow of funds, customer payouts, and FX transfers.
  • Implemented a ledger system to track fund movements between millions of bank accounts in response to various types of events.
  • Analyzed, transformed, and built dashboards for terabytes of transactional data using Bigquery, DBT, and Looker.
Technologies: Test-driven Development (TDD), Kubernetes, PostgreSQL, Ruby, Looker, BigQuery, Google Cloud Platform (GCP), Ruby on Rails (RoR)

Developer | Technical Architect

2016 - 2019
QTeam Software Solutions SRL
  • Designed and developed serverless multitier architectures on AWS API Gateway, AWS Lambda, CloudFront, S3, SNS, SQS.
  • Developed Python API endpoints continuously deployed on AWS Lambda using Jenkins pipelines and Bitbucket pipelines.
  • Implemented API webhooks where changes triggered in third-party systems are streamed into AWS Kinesis to be reliably processed.
  • Defined ETL processes, scheduled by the AWS data pipeline, to synchronize data from AWS RDS Aurora into AWS RedShift and build analytics.
  • Implemented a faceted search using Elasticsearch populated by AWS Lambda triggered by AWS CloudWatch Events or AWS RDS Aurora triggers.
  • Automated the provisioning and configuration of the infrastructure using AWS CloudFormation, EC2 Parameter Store, and Bitbucket Pipelines.
Technologies: System Advisor Model (SAM), AWS CloudFormation, Redshift, Data Pipelines, Amazon DynamoDB, Elasticsearch, Amazon ElastiCache, Relational Database Services (RDS), Amazon Kinesis, Amazon Simple Queue Service (SQS), Amazon Simple Notification Service (Amazon SNS), API Gateways, AWS Lambda, Python, Flask

Magento Developer | Technical Lead

2014 - 2015
Rocket Web
  • Implemented the back end for various components required for an eCommerce platform: catalog import, layered navigation, payment methods, shipping methods, checkout customization, order fulfillment, and more.
  • Migrated millions of records of catalog data, orders data, customers, subscriptions from legacy systems to new Magento Enterprise implementations.
  • Built Magento integrations for various third-party systems using different APIs, like SOAP and REST.
  • Developed enhancements for multiple Magento payment subscription extensions dependent on PayPal, Authorize.NET, and CyberSource as payment processors.
  • Defined the strategy and implemented automated test scenarios for subscription systems.
Technologies: Memcached, Behat, PHPUnit, Git, Apache, PHP, Magento

Web Developer | Technical Lead

2009 - 2014
  • Implemented new features and solved issues for a CMS developed in Django and Python to manage the main category page for a major US retailer.
  • Built and executed performance tests in JMeter and similar tools.
  • Implemented the infrastructure configuration and monitoring improvements.
  • Installed features on a high-traffic Magento EE website. Features included custom shipping and payment methods, refunds, exchange workflow integrated with warehouse APIs, multi-level marketing rewarding logic, and customer segments.
Technologies: Memcached, Varnish, Apache, MySQL, PHP, Magento, Python, Django

Java Developer, Team Lead, Team Manager

2004 - 2009
Advanced Mobile Applications
  • Developed J2ME applications and ported them on hundreds of mobile devices.
  • Integrated mobile carriers API to support monthly recurrent charges payment model.
  • Oversaw the development team allocation, project planning, and performance reviews.
Technologies: Django, Python, Qt, C++, J2ME, Java

Magento Debug | Magento Developer Toolbar
This is a Magento 1.x extension that offers insights about various Magento components during development: routing setup, execution timeline, database queries, configuration, and more.

eLearning Platform
This is a serverless platform deployed to AWS that uses multiple services to provide a scalable, highly available training platform for enterprise businesses from various industries (finance, education, aviation, etc)

THK's North America eCommerce Website
For this project, I had the role of a technical architect and developer in the build of THK's North American eCommerce.

Magneto Varnish
A Magento 1.x extension that was offering a full page cache implementation using Varnish.
2000 - 2004

Bachelor’s Degree in Mathematics and Computer Science

University Petrol-Gaze - Ploiesti, Romania


AWS Certified Solutions Architect - Associate

Amazon Web Services, Inc.


AWS Certified Solutions Architect Associate



Magento M1 Developer Plus

Magento U


Zappa, Experience API (xAPI), React, MobX, Rollbar, Requests


Bitbucket, AWS CloudFormation, Amazon Simple Queue Service (SQS), Amazon Simple Notification Service (Amazon SNS), Amazon CloudWatch, Docker Compose, Amazon CloudFront CDN, Boto 3, Pytest, IntelliJ IDEA, Vim Text Editor, Apache, Varnish, Behat, Tmux, BigQuery, Looker, Amazon ElastiCache, AWS IAM, AWS Key Management Service (KMS), Subversion (SVN), Git, Amazon Virtual Private Cloud (VPC), AWS Step Functions


Flask, Qt, PHPUnit, Ruby on Rails (RoR), Swagger, Symfony 3, Django, JSON Web Tokens (JWT)


Serverless Architecture, Continuous Integration (CI), Continuous Delivery (CD), Unit Testing, System Advisor Model (SAM), Test-driven Development (TDD)


Python, PHP, SQL, C++, Ruby, Go, JavaScript, Java, Bash


AWS Lambda, Magento 1, Contentful, Docker, Magento, Amazon Web Services (AWS), Google Cloud Platform (GCP), Kubernetes, J2ME, New Relic, Kaltura, Heroku


Amazon S3 (AWS S3), Data Pipelines, MySQL, Memcached, PostgreSQL, Amazon DynamoDB, Amazon Aurora, Redis, Elasticsearch, Redis Cache, Redshift


Amazon API Gateway, Amazon Kinesis, AWS CodePipeline, xAPI, Learning Tools Interoperability (LTI), PlantUML, API Gateways, Relational Database Services (RDS), SAML-auth, Performance Testing, LDAP, Continuous Monitoring, Okta

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