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open to work

var developer =
"Yeldos Sozakbay";

// C#/.NET Developer · Backend · databases & integrations

5 years of commercial backend development in C# and .NET (since 2021). I build server-side logic and integrations with external systems, and optimize queries in PostgreSQL and MS SQL Server.

Download CV PDF $ view --experience
Windows PowerShell 
<?xml version="1.0" encoding="UTF-8"?>
<developer>
  <name>Yeldos Sozakbay</name>
  <role>C#/.NET Developer</role>
  <location>Astana, Kazakhstan</location>
  <experience>4 years 10 months</experience>
  <skills>
    <skill>C#</skill> <skill>.NET</skill>
    <skill>PostgreSQL</skill> <skill>MS SQL</skill>
    <skill>Kafka</skill> <skill>Docker</skill>
  </skills>
</developer>

PS C:\Users\Yeldos> _
5
Years of experience
25+
Technologies
4
Certificates
3
Languages

01. Tech Stack

Languages

C#C# SQLSQL JSJavaScript JVJava HTHTML UMUML

Platform & practices

NT.NET MVMVC WFWindows Forms RSREST SPSOAP OOOOP / SOLID UTUnit Testing

Data & tools

PGPostgreSQL MSMS SQL Server NSNoSQL KFApache Kafka DKDocker GTGit CICI/CD SWSwagger JRJira SSStimulSoft LXLinux VSVisual Studio

02. Expertise

Backend & Integrations Backend

Business logic and APIs in .NET, integrations with external systems via SOAP and Apache Kafka, finding and fixing production issues.

REST SOAP Kafka
Databases & Performance Data

Table design and indexes, finding and optimizing slow queries using execution plans in PostgreSQL and MS SQL Server.

PostgreSQL MS SQL SQL
Async & Reliability Async

async/await and background processing so the UI and services never block; retries and logging for data exchange.

async/await Kafka Docker

03. Case Studies

01 Speeding up reports and database queries

Problem

Key reports and screens took too long to load, and some queries timed out on large data volumes. Users complained, and the database server load kept growing.

Result

Key report generation time dropped from 15 to 2 seconds, timeouts disappeared, and database server load decreased by 40%.

Solution

  • Analyzed slow queries using execution plans (EXPLAIN ANALYZE in PostgreSQL)
  • Rewrote heavy queries: removed redundant JOINs and unnecessary columns, replaced cursors and loops with set-based operations
  • Added missing and composite indexes, dropped unused ones
  • Moved long-running operations to asynchronous processing (async/await) so the UI stays responsive
C# .NET PostgreSQL

02 Asynchronous integration with external systems

Problem

The system had to exchange data with several external services and adjacent systems. Synchronous calls slowed down the main workflow, and when the other side was unavailable, data was lost or had to be resent manually.

Result

10+ external systems connected, thousands of messages processed daily, and manual resending is no longer needed. The main workflow no longer waits for external systems and doesn't depend on their availability.

Solution

  • Took part in designing and built the integration layer: SOAP for external APIs, Apache Kafka for asynchronous messaging between services
  • Implemented retries, error handling and logging, so a failure on one side no longer caused data loss
  • Worked with SOAP service contracts via WSDL, containerized services with Docker, and helped set up build and deployment via CI/CD
C# .NET SOAP WSDL Apache Kafka Docker CI/CD

03 Client-server module with business reporting

Problem

The business needed a new module for working with data and generating printable forms and reports. Previously, reports were compiled manually in Excel.

Result

The module was launched in a couple of months; reports are now generated automatically instead of being compiled by hand, saving dozens of hours per week. The module is used by thousands of employees.

Solution

  • Gathered requirements directly from the client together with the team, estimated timelines and effort, and presented the solution
  • Implemented the server-side business logic in .NET
  • Built the database schema for the module
  • Built reports and printable forms in StimulSoft Reports
  • Covered the core logic with unit tests; all code went through code review. Interns I supervised took part in development
C# .NET Windows Forms StimulSoft Reports PostgreSQL Unit Testing

04. Experience

  1. Middle .NET Developer @ PBSOFT

    Jun 2021 — Mar 2026 · 4 years 10 months

    Developing and maintaining server-side applications and services in C# and .NET: business logic, database work and integrations with external systems.

    • Implemented business logic and client-server modules to technical specifications
    • Built and optimized database schemas and SQL queries (PostgreSQL / MS SQL Server)
    • Integrated external APIs and third-party systems (SOAP, Apache Kafka)
    • Used async/await so the system doesn't block on long-running operations
    • Took part in code reviews and followed clean code standards
    • Mentored and onboarded interns
    • Estimated task effort and complexity, forecast development resources
    • Worked directly with clients: gathering requirements and presenting solutions
    C# .NET PostgreSQL MS SQL Kafka Agile/Scrum

05. GitHub

$ git log --contributions --since="1 month ago"
Mon Tue Wed Thu Fri Sat Sun 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 1 2 3 4 5 6 7 8 9 10 11
39 contributions in the last month less more
$ git log --oneline -5
Open GitHub profile →

06. Education

$ git log --education
  • 2024
    Bachelor's · Applied Informatics
    Siberian Institute of Business and Information Technologies
    Omsk · Applied Informatics in Economics
  • 2025
    The Complete Xamarin Developer Course
    Udemy
    Professional development course
  • 2025
    PostgreSQL Certification Course
    W3Schools
    Professional development course
  • 2020
    Software Development
    IT STEP Academy
    Professional development course
$ ls ./certificates
  • Udemy Xamarin Developer: iOS & Android
    Digital certificate · 2025
  • W3Schools PostgreSQL Certification Exam
    Digital certificate · 2025
  • Cisco CCNA: Networking
    Digital certificate · 2019
  • Cisco CCST: Cybersecurity
    Digital certificate · 2019
  • Applied Informatics
    Relevant university degree + international Cisco certifications

07. How I Work

“
I take part in code reviews and stick to OOP, SOLID and Clean Code — code should be as easy to read as it is to write.
CR Code quality Clean Code · SOLID · Agile/Scrum
“
I onboard interns and help them grow their technical skills — a strong team matters more than one strong developer.
MT Mentoring Clean Code · SOLID · Agile/Scrum
“
I talk to clients directly: clarify requirements, show solutions and stay focused on results under tight deadlines.
PM Working with clients Clean Code · SOLID · Agile/Scrum

08. Languages

KZ

Kazakh

Native

RU

Russian

C1 — Advanced

EN

English

B2 — Upper-intermediate

contact.ps1

> Let's Work Together

Looking for a .NET backend developer role (Middle): full-time, part-time or project work. On-site, hybrid or fully remote; ready to relocate and travel.

$ send --message Download CV