Mert Yalhi, Developer in Brno, South Moravian Region, Czech Republic
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Mert Yalhi

Verified Expert  in Engineering

Software Developer

Brno, South Moravian Region, Czech Republic

Toptal member since May 26, 2021

Bio

Mert is a software architect with more than 10 years of professional software development experience who also gained leadership skills in various projects. He built horizontally scalable back ends based on various modern technologies and front ends with modern, highly interactive UIs. Millions of users are using the solutions he created. Mert is passionate about developing robust, scalable, and distributed enterprise software solutions that will be used by a large number of users.

Portfolio

NewStore
TypeScript, Terraform, Kubernetes, Amazon DynamoDB, Go, Python, NestJS...
Nuvia
Node.js, React, React Native, MongoDB, InfluxDB, Apache Kafka, Elasticsearch...
Trilogy
.NET, C#, JavaScript, Node.js, React, Java, Amazon Web Services (AWS)...

Experience

  • DevOps - 11 years
  • JavaScript - 11 years
  • Microservices - 9 years
  • Amazon Web Services (AWS) - 8 years
  • Node.js - 6 years
  • React - 4 years
  • TypeScript - 4 years
  • Terraform - 2 years

Availability

Part-time

Preferred Environment

Visual Studio Code (VS Code), Visual Studio, Git, IntelliJ IDEA

The most amazing...

...thing I've built recently is an IoT platform that currently serves over 100,000 IoT devices and processes over 10 million telemetries per hour.

Work Experience

Senior Software Engineer II

2020 - PRESENT
NewStore
  • Built fiscal integrations for various countries, which resulted in an increase of over $100 million GMV.
  • Built fiscal printer integration through the cloud using existing platform components, unlocking multiple global brands.
  • Built solutions and adjusted infrastructure to achieve SOC-2 compliance.
  • Provided company-wide tools and services that are used for improving the robustness of our platform.
Technologies: TypeScript, Terraform, Kubernetes, Amazon DynamoDB, Go, Python, NestJS, React Native, React, Amazon EKS, AWS IoT Core, Amazon Elastic Container Service (ECS), Amazon API Gateway, Amazon Web Services (AWS), Microservices

Engineering Manager

2019 - 2020
Nuvia
  • Led the engineering team and R&D initiative across the company.
  • Handled performance improvement and bottleneck elimination tasks on the core IoT back end, which increased the transaction processing capacity from 150,000 ops per hour to over 2,000,000 ops per hour.
  • Identified and fixed vulnerabilities within the cloud architecture, back-end services, and embedded solutions.
  • Built an analytics platform that handles a billion telemetries per hour.
  • Performed management activities, including defining development processes, leading productivity improvement methods, and deciding on tools and services to support the team.
Technologies: Node.js, React, React Native, MongoDB, InfluxDB, Apache Kafka, Elasticsearch, Kubernetes, AWS Lambda, C++, Assembly, Amazon Web Services (AWS), Microservices

Chief Software Architect

2017 - 2019
Trilogy
  • Built in-house tools and services for quality management, analytics, intelligent ticket routing, article search and suggestion, prediction, and decision support based on ML methods, such as classification, clustering, and NLP.
  • Maintained over 20 in-house projects, actively used by over 10,000 end users and more than 200 internal users monthly.
  • Managed end-to-end software development lifecycle, including requirements elicitation, design, implementation, testing, deployment, CI/CD, and maintenance.
  • Built an in-house data analytics platform for Zendesk, which automated business metrics.
  • Built a customer call analysis service, which uses natural language processing (NLP) and machine learning; the service was used to convert customer calls to transcripts (speech-to-text) and analyze the sentiments.
  • Designed and implemented automated unit test tools, which automated unit tests for more than 50 enterprise projects.
  • Built code analysis tools and automated unit test generators that use machine learning algorithms.
Technologies: .NET, C#, JavaScript, Node.js, React, Java, Amazon Web Services (AWS), Microservices

Senior Software Architect

2016 - 2017
AAA Information Technologies
  • Provided turnkey engineering solutions specialized in software, information security, and system integration.
  • Provided tailor-made solutions for information security, such as penetration testing and security audits.
  • Performed cloud migration and data integration for the existing services.
Technologies: C#, .NET, C++, Amazon Web Services (AWS), Microservices

Software Architect

2014 - 2016
Argate
  • Led various government projects for real-time data acquisition system development and 3rd-party integrations, including water and wastewater monitoring systems and a continuous emission monitoring system.
  • Provided consultancy to several government agencies on secure software development and penetration testing.
  • Built web applications that had more than four million monthly active users.
Technologies: .NET, C#, Microsoft SQL Server, JavaScript, Microservices

Software Developer

2013 - 2013
North Atlantic Treaty Organization (NATO HQ)
  • Designed and developed secure services and secure authentication solutions based on the standards defined by NCIA and NSA.
  • Created Microsoft Office add-ins that processed the content of the documents and performed document classification validations.
  • Created a SharePoint-integrated web application that served as a document management and validation system for public documents.
Technologies: C#, SharePoint

Software Engineer

2009 - 2012
Argate
  • Led the palm vein verification system project for the Turkish Ministry of National Education, which is actively used by more than 400,000 students in more than 1,000 schools and 2,000 government research centers.
  • Worked on protocol reverse engineering and communication interception for low-level M2M communications (UART, I2C, and SPI).
  • Built an end-to-end data acquisition system solution that collected telemetry data from devices in different locations and performed analysis and reporting on the data in a central location.
Technologies: .NET, C#, ASP.NET, ASP.NET MVC, C++

Software Engineer

2008 - 2009
5th World Water Forum Secretariat
  • Built a registration system used by 33,000 users. It also processed more than €3 million in online POS transactions.
  • Implemented a security management system that provided information on the participants to the Turkish National Police and National Intelligence Organization via web service integration.
  • Created an integration with the Ministry of Foreign Affairs that automated the visa application process for the participants.
Technologies: ASP.NET, C#, PHP

Experience

IoT Platform

An IoT platform that serves multiple IoT products owned by different manufacturers. I designed and developed the platform in only three months. It replaced the previous IoT back end of Nuvia, a Turkish IoT company that provides smart energy solutions.

The previous IoT back end had bottlenecks, which I solved. Still, it did not allow us to integrate new IoT hardware with different communication protocols and couldn't scale horizontally. We decided to build a new platform that replaced the previous IoT back end and migrated all devices to the new platform without any downtime, a seamless transition.

The new IoT platform can scale to support an infinite number of devices and process an unlimited number of telemetries. With a completely similar infrastructure to the previous back end, it can process five times more telemetries. By building this new platform, we've allowed the onboarding of four new companies and increased our device count to more than 100,000 by hosting their devices in a couple of months. It currently serves over 100,000 IoT devices and processes over 10 million telemetries per hour. It also provides real-time data to tenants and useful insights to end users based on the underlying analytics services.

ML-backed Decision Support System for Customer Support

Designed and built an ML-backed decision support system for the customer support department that served over 50 brands and 500,000 customers. The system supported around 200 support agents by providing preliminary analysis on the customer issue and suggested possible solutions and linked issues.

System features:
• NLP-based input analysis that analyzes customer requests.
• Classification of the customer support request based on the predefined workflows and KB articles.
• Clustering of the support cases for a product, which provides insights to the product owners for improving the product and service.
• Automated SEV 1 issue discovery, which detected SEV 1 issues based on customer requests and automatically escalated them to the L2 and L3 agents and product team.

ML-backed Intelligent Ticket Routing System

Designed and built an ML-backed intelligent ticket routing system that routed incoming support tickets to the support agents based on the ticket content, previous customer interactions, and support agent workload.

Features and results:
• Routed tickets to a preferable support agent by analyzing the requested content with NLP and matching agent skills.
• Reduced support agent workload by routing the tickets based on agent workload.
• Reduced initial response time to less than minutes.
• Reduced average resolution time to less than 45 minutes.
• Increased one-touch resolution by 60%.

Analytics Platform

I built an analytics platform that measured and reported customer support and support agent metrics. The system integrated the support system (Zendesk), employee monitoring system, and several other products.

Features:
• Real-time integration to Zendesk.
• Integration to the employee monitoring system for reporting support agent performance metrics.
• Integration to the supported products for providing support-related metrics of the products.
• Provided personalized support metrics to the support agents.
• Provided product-based support metrics to the product owners.
• Provided support department health metrics to the management.

Education

2016 - 2018

Master's Degree in Computer Science

Hacettepe University - Ankara, Turkey

2014 - 2017

Master's Degree in Software Engineering

Hacettepe University - Ankara, Turkey

2007 - 2011

Bachelor's Degree in Computer Technology and Information Systems

Bilkent University - Ankara, Turkey

2005 - 2007

Bachelor's Degree in Mathematics and Computer Science

Cankaya University - Ankara, Turkey

Skills

Libraries/APIs

Node.js, React

Tools

GitLab CI/CD, GitLab, Terraform, RabbitMQ, Visual Studio, Git, IntelliJ IDEA, Amazon EKS, Amazon Elastic Container Service (ECS)

Languages

TypeScript, C#, JavaScript, C++, PHP, Java, Assembly, Go, Python

Frameworks

.NET, ASP.NET, ASP.NET MVC, Express.js, React Native, NestJS

Paradigms

DevOps, Microservices, DevSecOps

Platforms

AWS Lambda, Amazon Web Services (AWS), Kubernetes, SharePoint, Apache Kafka, Zendesk, Visual Studio Code (VS Code), AWS IoT Core

Storage

MongoDB, InfluxDB, Microsoft SQL Server, Amazon DynamoDB, Elasticsearch, PostgreSQL, Redis

Other

CI/CD Pipelines, Security, GitOps, Machine Learning, Natural Language Processing (NLP), Classification Algorithms, K-means Clustering, Generative Pre-trained Transformers (GPT), Amazon API Gateway

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