Denis Mikhalev

Senior Software Engineer (C# / Go) High-Performance Distributed Systems · Scalable Microservices · Performance Optimization · Azure Certified

Summary

C# and Go developer with 7+ years of experience in full-cycle software development — from gathering requirements to delivering scalable, high-performance applications with CI/CD and high test coverage. Worked on large-scale projects at Litmos, Bosch (ETAS), and Citibank, focusing on architecture, building services from scratch, and performance optimization. Collaborated with international teams from the USA, Germany, and Australia. Open to relocation & remote work.

Experience

Full-stack Software Engineer — Litmos

May 2023 — Present | US-based SaaS LMS platform

Migrated the legacy bulk course completion service (previously based on SQL stored procedures) to a modern .NET 7.0 Windows service using Azure Service Bus, resulting in a 74% reduction in data processing time, elimination of recurring errors, and significantly reduced database load.
Integrated encoding.com into video processing and normalization applications.
Built a Salesforce integration: the Litmos app opens inside a Salesforce canvas (iframe) with authentication and automatic user provisioning on first open.
Built the Litmos-side backend that synchronizes data between Litmos and Salesforce.
Built a granular roles and permissions system, enabling fine-tuned user access management and supporting enterprise-level client needs.
Implemented randomized task prioritization in queue processing by assigning random weights to new records, replacing a FIFO strategy — ensuring fairer task distribution and reduced delays for low-frequency requestors.
Optimized the report generation engine, reducing report processing time from 35 minutes to 1 min 15 sec (96% improvement).
Eliminated a long-standing data duplication bug (present since the product’s inception) that generated tens of thousands of duplicate records monthly under high load — fixed with SQL Server locking hints and de-duplication guards in stored procedures, reducing duplicates to zero and support workload by 17%.
Fixed critical frontend accessibility issues, lowering accessibility-related errors from 67 to zero.
Eliminated memory leaks in a key Windows service that previously caused system degradation and outages, restoring system stability.

Software Engineer — ETAS / Bosch

Jun 2022 — May 2023 | Automotive software, Germany

Enhanced ETAS MDA V8, a WPF-based signal analysis tool used by automotive engineers at major car manufacturers worldwide.

Implemented signal replacement on diagrams, configuration saving, and individual time shifts — reducing manual work by ~34%.
Stabilized the video instrument, resolving desync and freezing issues affecting 17–20% of use cases.
Added automated UI test suite, increasing crash-free user rate by ~27%.
Refactored legacy code to SonarQube standards, reducing technical debt by 62%.

Software Engineer — Citibank

Jul 2021 — Jun 2022

Developed and integrated 10+ automated reports into a WinForms back-office application for Visa/MasterCard operations — reducing manual Excel work by up to 81%.
Implemented quarterly regulatory reporting modules for Central Bank compliance.
Created fraud-detection reporting modules enhancing visibility into suspicious transactions.
Refactored legacy SQL stored procedures, improving report generation speed.
Designed database views excluding sensitive PII for privacy and compliance.

Software Engineer — Frontdesk24

Aug 2019 — Jul 2021

Independently designed and implemented API integrations between the SaaS hotel management platform and major OTAs: Booking.com, Expedia, Channex.io, Bronevik.com, OneTwoTrip, NashTravel.
Reduced booking processing time from 2+ minutes to 1–2 seconds.
Fixed memory leaks and critical backend issues, removing the need for weekly service restarts.
Built and maintained core features of the cloud hotel management system (SaaS).

Litmos, ETAS/Bosch, and Citibank positions through EPAM Systems (Jul 2021 — Present).

Side Project

Technical Owner — Voicetrics

2026 — Present | voicetrics.com | AI call analytics for businesses

A production SaaS built in Go, with the AI-related modules in Python. As technical owner I’m responsible for the architecture and end-to-end engineering: ingestion pipeline, speech recognition, LLM scoring, analytics UI, licensing, installer and deployment.

Ships two ways from one codebase: an on-prem Windows install and a multi-tenant cloud version, where tenants are isolated as separate processes and databases behind their own subdomains (systemd, nginx) rather than a tenant column.
Built a pluggable speech-to-text layer with four interchangeable engines, lazily loaded so unused heavy dependencies never enter memory — switching a customer’s engine is a config change.
Kept the proprietary scoring engine server-side behind an HTTP contract, so no analysis IP ships to customer hardware and only the transcript — never the audio — leaves an on-prem install.
Implemented offline licensing: Ed25519-signed tokens verified without network access, machine fingerprinting, self-service trials and heartbeat telemetry.
Stack: Go, Python (AI modules), LLM & STT APIs, Linux VPS.

Education

Master of Science — Software Engineering Southern Federal University | 2015 — 2017

Bachelor of Science — Computer Science Southern Federal University | 2012 — 2015

Certifications

Microsoft Certified: Azure Fundamentals (AZ-900)
Asynchronous Programming in C#
Building in Azure AI Foundry
Build AI Assistants with Azure AI Foundry

Technical Skills

Languages & Frameworks: C#, Go, .NET Core / .NET 7, .NET Framework, ASP.NET Core, ASP.NET MVC, Entity Framework Core, WPF, WinForms, Windows Services, Python, FastAPI

AI: LLM integration, prompt engineering, speech-to-text pipelines

Cloud & Infrastructure: Microsoft Azure, Azure Functions, Cosmos DB, Azure Service Bus, Azure AI, Azure DevOps, Docker, Terraform

Frontend: Razor, JavaScript, jQuery, Bootstrap, HTML, CSS, Accessibility (WCAG)

Databases: MS SQL Server, T-SQL, Cosmos DB, Redis, Entity Framework Core, Dapper, Database Design, Query Optimization, Stored Procedures

APIs & Integrations: REST, SOAP, WCF, GraphQL, JWT, Salesforce (Canvas), encoding.com

Architecture: Microservices, Event-Driven Architecture, CQRS, MediatR, Distributed Systems, System Integration

Testing: xUnit, NUnit, Moq, Selenium, SonarQube

Practices: CI/CD (GitHub Actions, Azure DevOps, Jenkins), Performance Optimization, Git

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