
Theodoros Goulas
Verified Expert in Engineering
Software Developer
Athens, Central Athens Regional Unit, Greece
Toptal member since October 26, 2022
Theodoros is a software engineer with over 7 years of experience as a back-end and full-stack developer. He specializes in cloud engineering and machine learning applications with a strong web app development background in the financial industry. Theodoros has studied computer science at the National Technical University of Athens and has obtained a master's degree in machine learning and artificial intelligence from the National Center for Scientific Research "Demokritos."
Portfolio
Experience
- Java - 6 years
- Microsoft SQL Server - 6 years
- Software Deployment - 6 years
- Python - 4 years
- Docker - 3 years
- Amazon Web Services (AWS) - 3 years
- Machine Learning - 2 years
- Jenkins Pipeline - 2 years
Availability
Preferred Environment
Windows, PyCharm, IntelliJ IDEA
The most amazing...
...app I've developed is a prototype integrated with AWS that extracts data from financial messages and produces statistical metadata and ML insights.
Work Experience
[Phase 2] [Toptal Teams] Back-end developer for a Data Services Dashboard Redesign
National Center for Atmospheric Research - General
- Redesigned the application dashboard using React with an Elasticsearch integration, optimizing the indexing capabilities.
- Created a set of API services, enabling communication between the font-end React application and the Elasticsearch index.
- Created the migration and data ingestion process from the existing MySQL database to the Elasticsearch index.
Technical Lead
PaymentComponents
- Developed a multi-platform solution using LLMs (OpenAI, Llama, Mistral) with LangChain, allowing users to query large document corpora and databases, retrieve results, generate plots, and perform advanced data analyses.
- Implemented a set of API services designed as multi-agent processes for communication with LLMs via LangChain. Features include retrieval-augmented generation (RAG), natural language-to-SQL conversion, and code generation.
- Built the application as a modular solution to support on-premise installations via Docker containers and AWS-hosted serverless architecture (Lambda, Cognito, S3, Step Functions, RDS), using the Pulumi framework.
- Implemented a CI/CD pipeline with AWS CodePipeline and Git integration for automated build and test. Used Pulumi TypeScript scripts for AWS resource provisioning, built Docker images, and pushed them to Amazon ECR.
Junior Python Developer | SaaS Company
Pierre Rappolt
- Integrated the application with the Google, Zoom, Jamf, and Okta APIs.
- Refactored the code by extracting a set of interfaces and classes, increasing the reusability and reducing the maintenance effort. As a result, the import process of the new API integration into the application was simplified drastically.
- Implemented unit tests per API integration using the Python unittest and asyncio libraries.
Full-stack Software Engineer
PaymentComponents
- Designed, developed, and provided operational support in large-scale web applications for Cardlink, Greece's largest card acceptance network.
- Built an extensive set of batch processes handling Cardlink's bank and merchant billing processes.
- Performed development tasks in an account aggregator application that provides fintech and payment institutions a unified way to connect with banks, incorporating batch processes and web connection using API calls through the PSD2 protocol.
Software Engineer
Cognity
- Assisted as a team member in developing an EPOS application for Vivacom, the largest telecommunications company in Bulgaria.
- Redesigned and transformed the monolithic Java 6 Vivacom EPOS application into a modern system with a Java 8 microservices back end and a React and Node.js front end.
- Collaborated in every step of the application's lifecycle, including design, development, deployment, continuous integration, and operational support.
Experience
Explainable Multivariational Anomaly Detection Model
https://github.com/teogoulas/explainable-multivariational-anomaly-detectionCardlink Apollo Web Application
https://apollo.cardlink.gr/login#enFinaplo.AI
https://www.paymentcomponents.com/finaplo-ai/Cardlink Admin Portal
https://mrchnt.cardlink.gr/Education
Master's Degree in Artificial Intelligence and Machine Learning
University of Pireaus - Pireaus, Greece
Master's Degree in Computer Science
National Technical University of Athens - Athens, Greece
Skills
Libraries/APIs
React, Node.js, REST APIs, PyTorch, TensorFlow, Pandas, jQuery, Jenkins Pipeline, Amazon EC2 API, Python API, Asyncio, SQLAlchemy, AMQP
Tools
PyCharm, IntelliJ IDEA, GitLab, Git, GitHub, Amazon SageMaker, Apache Tomcat, Jenkins, Docker Compose, Pytest, Amazon Simple Queue Service (SQS), Amazon Cognito, NGINX, AMQP-Processing, AWS CloudFormation, Amazon Elastic Container Registry (ECR), AWS Step Functions, AWS Glue
Languages
Python, Java 8, Java, SQL, Groovy, JavaScript, CSS, HTML, Python 3, TypeScript
Frameworks
Spring 5, Spring Boot, Spring Microservice, Spring, Hibernate, React Native, Django, Redux, Grails, Next.js, Angular, Thymeleaf, JUnit, Spring Batch, Django REST Framework, Tailwind CSS
Paradigms
Microservices Architecture, Microservices, REST, Continuous Integration (CI), Serverless Architecture, ETL, Object-relational Mapping (ORM), Unit Testing
Storage
Microsoft SQL Server, Databases, PostgreSQL, MySQL, Elasticsearch, Amazon DynamoDB, NoSQL, Data Pipelines
Platforms
Windows, Amazon Web Services (AWS), Docker, Linux, AWS Lambda, Nexus, Azure, Visual Studio Code (VS Code), Oracle, DigitalOcean
Other
APIs, Back-end, Back-end Development, Full-stack, Web Services, Computer Science, Software Deployment, Web Development, Algorithms, Cloud, API Integration, CI/CD Pipelines, Infrastructure as Code (IaC), Amazon RDS, Fintech, Data Processing, Data Engineering, SaaS, FastAPI, ETL Tools, Electrical Engineering, Machine Learning, Data Science, Computer Vision, Artificial Intelligence (AI), LDAP, Serverless, AWS Auto Scaling, Data Warehousing, Protocol Buffers, Microsoft Azure, State Machines, Amazon API Gateway, Integration Testing, Cloud Applications, LangChain, Pulumi, Lambda Functions, AI Agents, Data Modeling
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