Gergely is available for hire
Hire GergelyGergely Pósfai
Verified Expert in Engineering
Distributed Systems Developer
Barcelona, Spain
Toptal member since March 10, 2022
Bio
Gergely is a skilled back-end engineer that has extensive international experience. He likes to work with Google Cloud Platform (GCP) and AWS. Gergely mainly has experience with Java but also does some development in Python and Go when clients request it.
Portfolio
Glovo
Java, Amazon Web Services (AWS), RDBMS, Spring, Jira, Distributed Systems, SQL...
Gravity R&D
Google Cloud Platform (GCP), Java, AWS Data Pipeline Service, Python, Jira...
Amazon.com
Amazon Web Services (AWS), Java, Amazon S3 (AWS S3), Amazon DynamoDB...
Experience
- Java - 10 years
- SQL - 6 years
- RDBMS - 6 years
- Amazon Web Services (AWS) - 4 years
- Distributed Systems - 4 years
- Google Cloud Platform (GCP) - 2 years
- Amazon DynamoDB - 2 years
- Spring Boot - 2 years
Availability
Part-time
Preferred Environment
Linux, IntelliJ IDEA, Gmail, Google Meet, Zoom
The most amazing...
...thing I've done is I started an initiative to evaluate mutation testing and see if it can improve the team development process.
Work Experience
Software Engineer
2020 - PRESENT
Glovo
- Designed the integration with a new chat provider to provide customer-courier chats for Glovo users. Worked together with client teams to split up responsibilities and coordinated with several back-end engineers throughout the implementation.
- Designed and implemented a system to send notifications to customers when their order delivery is late, reducing order cancellations by 1.7 PP.
- Reviewed integration with Glovo's external CRM provider and identified and fixed inefficiencies saving around 192,000 Euros a year by reducing Glovo's usage of the CRM APIs.
- Conducted around 70 interviews, wrote and tested new interview questions and defined a process for engineers to write new interview questions.
- Explored and researched mutation testing in practice and did presentations for engineers across the company.
- Supervised the extension of the existing phone number masking feature for customer-courier calls making it possible to mask phone numbers for courier-partner calls as well.
Technologies: Java, Amazon Web Services (AWS), RDBMS, Spring, Jira, Distributed Systems, SQL, Amazon S3 (AWS S3), Spring Boot, Postman, Linux, IntelliJ IDEA, Gmail, Zoom, APIs, Software Architecture
Software Development Engineer
2019 - 2020
Gravity R&D
- Designed and implemented a distributed parallel precomputation process on GCP (using preemptible compute engine instances) to speed up item recommendation for customers resulting in a 98.5% reduction in the average recommendation time.
- Created an ETL pipeline using AWS Data Pipeline Service for training predictive models for Disney+ and Hotstar to forecast customer behavior for around 30 million users.
- Implemented caching for item images in the recommendation system using Google Cloud Storage with Cloud CDN reducing the average image loading time by approximately 81%.
Technologies: Google Cloud Platform (GCP), Java, AWS Data Pipeline Service, Python, Jira, Distributed Systems, RDBMS, SQL, Spring, Docker, Linux, IntelliJ IDEA, Gmail, Google Meet, Software Architecture
Software Development Engineer
2017 - 2019
Amazon.com
- Worked on the distribution of Prime Video to 3P devices, which involved working closely with partners (like LG, Samsung, Vizio, Deutsche Telekom, Netgem, and others) to port the app to new TV set-top boxes used by around 10 million customers.
- Developed services to automate internal cross-team processes to speed up the integration process of new partner devices (TV or set-top-box models), reducing the onboarding process from around two months to around one week.
- Investigated and fixed device specific bugs and issues coming from both partners and customers. This includes on-call shifts and participation in on-site workshops with partners (e.g. LG) as well.
Technologies: Amazon Web Services (AWS), Java, Amazon S3 (AWS S3), Amazon DynamoDB, AWS Lambda, Jira, Distributed Systems, RDBMS, SQL, Docker, Linux, IntelliJ IDEA, APIs, Software Architecture
Assistant Research Fellow
2015 - 2017
Technical University of Budapest
- Taught data analysis using R and software technologies (SQL, Java, Python) to university students.
- Wrote papers on trust-aware recommendation systems.
- Designed university classes on text mining using R.
Technologies: R, Java, Python, SQL
Software Developer
2012 - 2017
Alerant Zrt
- Developed an app that notifies customers if they lose items. The app communicated with small Bluetooth devices that customers could attach to their belongings (like wallets and keys). Took part in the back-end API and Android app development.
- Developed SIP session replication for JBoss7 using JBoss Infinispan, a type of a distributed cache).
- Developed a plugin system for an RCS client mobile app, which allowed developers to write plugins for the mobile app in JavaScript, leveraging the exposed APIs of the app (e.g., contacts, messages, camera, etc.).
Technologies: Java, Android, RDBMS, Jira, SQL, APIs, Software Architecture
Experience
BabySmile (Android App)
BabySmile is a straightforward baby-selfie app for Android that allows parents to take photos of their baby while enjoying their favorite YouTube video or some other content on their phone. After the BabySmile app is started, parents can create something else on the phone that their baby likes and then capture the baby's smile by tapping the small camera preview in the corner of the screen. Pictures can also be taken automatically using face detection.
I did the entire project by myself, including the UI design, client-side development, and the development of the back-end services as well. There are only a few small back-end services used by the app, which were written in Go and are running on App Engine on GCP.
I did the entire project by myself, including the UI design, client-side development, and the development of the back-end services as well. There are only a few small back-end services used by the app, which were written in Go and are running on App Engine on GCP.
Education
2014 - 2017
Coursework Toward PhD in Informatics Sciences
Budapest University of Technology and Economics - Budapest, Hungary
2012 - 2014
Master's Degree in Computer Engineering
Budapest University of Technology and Economics - Budapest, Hungary
2008 - 2012
Bachelor's Degree in Computer Engineering
Budapest University of Technology and Economics - Budapest, Hungary
Certifications
JANUARY 2019 - JANUARY 2021
AWS Certified Solutions Architect
Amazon Web Services
Skills
Tools
Jira, Postman, IntelliJ IDEA, Google Meet, Zoom
Languages
Java, SQL, R, Python, Go
Platforms
Amazon Web Services (AWS), Google Cloud Platform (GCP), Android, AWS Lambda, Docker, Linux
Storage
RDBMS, Amazon S3 (AWS S3), Amazon DynamoDB, AWS Data Pipeline Service
Frameworks
Spring, Spring Boot
Other
Distributed Systems, APIs, Software Architecture, Systems, Machine Learning, Data Mining, Natural Language Processing (NLP), Trust-Aware Recommender Systems, Gmail, Generative Pre-trained Transformers (GPT)
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