Oleg C. — Senior Full-Stack Engineer, Lead

Vetted expert in Full Stack Web (6.0 yr.), Back-End Web (6.0 yr.).

Last verified on December, 2025

Architect/Team-lead

Upper-Intermediate English

Core Skills

SQL

5 yr.

NestJS

5 yr.

Express

5 yr.

Bio Summary

Versatile Full Stack Engineer/Lead with over 6 years of experience, specializing in creating robust web platforms and SaaS applications. Expertise in TypeScript, JavaScript, SQL, and a range of backend technologies including NestJS, Express, and TypeORM. Proficient in database management with Postgres, MySQL, MongoDB, and utilizing Redis and similar key-value stores, Familiar with AWS, GCP, and Azure. Skilled in CI/CD pipelines, Docker, caching, and queuing mechanisms, along with comprehensive testing abilities using Jest and Postman.A strong grasp of software architecture, particularly in microservices and event-driven systems, with a background in developing financial systems, IoT, and productivity tools.

Technical Skills

Programming Languages	JavaScript, TypeScript
JavaScript Frameworks	Backbone.js, Express, NestJS
AI & Machine Learning	OpenAI
Databases & Management Systems / ORM	SQL
Amazon Web Services	AWS ELB, AWS SQS
Azure Cloud Services	Microsoft Azure API
Blockchain and Decentralized Software	Bitcoin Blockchain
Deployment, CI/CD & Administration	CD DevOps pipelines
Platforms	CRM
Collaboration, Task & Issue Tracking	Jira
Methodologies, Paradigms and Patterns	microservices, SSR
SDK / API and Integrations	Microsoft Azure API
Message/Queue/Task Brokers	RabbitMQ
Mail / Network Protocols / Data transfer	SSE, WebSockets
Operating Systems	Unix
Other Technical Skills	Facebook Ads API, Queues, RDS

Bidel (Fiat Exchange Platform) - Full-Stack Developer, Tech Lead

Duration: Dec 2024 – Present

Technologies: NestJS, PostgreSQL, RabbitMQ, Redis, AWS, Datadog

About the project: Fiat exchange platform with microservice, event-driven architecture.

Responsibilities:

Designed and led development of the platform architecture
Built modular integrations for KYC, Twilio (SMS and conference calls), payment processing, exchange rate services, and analytics
Implemented system monitoring, rate limiting, WAF, and Redis-based caching and security layers

PeerPe (P2P Fiat Application) - Backend Team Lead

Duration: Jan 2024 – Oct 2025

Technologies: NestJS, PostgreSQL, AWS (ELB, RDS, SQS), Redis

About the project: P2P fiat platform enabling peer-to-peer transactions.

Responsibilities:

Led a backend team of three developers to build the platform from scratch
Designed and implemented the full order lifecycle, including dispute resolution and auto-cancellation logic
Developed customer support system and real-time chat functionality using WebSockets

TaskPulse (Task Management System) - Back-End Developer

Duration: Mar 2024 – Mar 2025

Technologies: NestJS, PostgreSQL, Redis, Azure, OpenAI

About the project: Task management and productivity platform with integrated email and AI features.

Responsibilities:

Built the full backend for the platform
Developed Pomodoro tracker with real-time WebSockets
Integrated Gmail/Outlook APIs for unified inbox feature
Implemented database encryption for sensitive data
Integrated OpenAI with strictly typed responses

Luminex (IoT Projector Management) - Backend Team Lead

Duration: Apr 2024 – Jul 2024

Technologies: NestJS, MongoDB, PostgreSQL, Redis

About the project: IoT-based projector system management platform.

Responsibilities:

Led a backend team of 2–3 developers
Designed CRM and client application architecture
Integrated payment systems and implemented subscription and appointment booking workflows

Firbo IO (Developer Productivity Analytics) - Backend Lead

Duration: Feb 2023 – Present

Technologies: NestJS, PostgreSQL, GCP, Redis

About the project: Platform that integrates with developer tools to analyze work evidence, identify outliers, and provide productivity insights.

Responsibilities:

Led backend development and integrations with Jira, Google, GitHub, and Bitbucket
Managed and processed large datasets for evaluation algorithms
Implemented daily auto-update tasks and custom SQL queries for analytics charts
Developed Docker automation scripts and backend obfuscation workflows

PuzzlePizza (Kitchen Management System) - Back-End Developer

Duration: May 2022 – Feb 2023

Technologies: NestJS, PostgreSQL, AWS, Stripe, Square, Redis, Monorepo

About the project: Kitchen management system with mobile and self-terminal backends.

Responsibilities:

Developed database schema and architecture from scratch
Handled client, admin, and printer services
Integrated POS terminals and printers
Integrated Stripe/Square payments and implemented SSR admin panel

Amres / Nextres (Investment Lending Platform) - Backend Developer / Team Lead

Duration: Jan 2022 – May 2022

Technologies: Node.js, NestJS, Express, Carbone.io, MongoDB, PostgreSQL, AWS

About the project: Multi-service investment lending platform.

Responsibilities:

Supported and extended platform functionality
Developed admin panel for document generation (management, sorting, attribute matrices, template conversion to DOCX/PDF)
Implemented e-signature service with platform integration, step logs, and email notifications

Fatster / Nutrimis (Social Fitness App) - Back-End Developer

Duration: Aug 2021 – Jan 2022

Technologies: NestJS, Express, TypeScript, PostgreSQL, WebSockets, AWS

About the project: Social fitness app aimed at weight loss.

Responsibilities:

Supported and enhanced backend functionality
Implemented WebSocket chat server and optimized SQL queries
Automated build process via Jenkins and improved server architecture
Added premium features (subscriptions, in-app purchases, user statistics)

CPayments (Cryptocurrency Exchange) - Back-End Developer

Duration: Apr 2021 – Aug 2021

Technologies: NestJS, Express, TypeScript, PostgreSQL, SSE

About the project: Upgrade of an existing cryptocurrency exchange platform.

Responsibilities:

Developed Bitcoin buy/sell functionality
Designed database schema and built client and admin backends
Implemented callback server and launched Bitcoin node
Added real-time updates using Server-Sent Events (SSE)

TrafficApps (Mobile App Advertising Platform) - Back-End Developer

Duration: Dec 2020 – Aug 2021

Technologies: NestJS, Express, TypeScript, MySQL, AWS (EC2, RDS, S3, SES)

About the project: Platform for mobile application advertising.

Responsibilities:

Built REST APIs and payment integrations (fiat/crypto)
Worked with Facebook Ads Manager
Implemented traffic filtering settings based on various parameters
Developed SSR admin panel

Test Orchestrator (CI Testing Framework) - Back-End Developer

Duration: Aug 2020 – Mar 2021

Technologies: NestJS, Express, TypeScript, MySQL, AWS (EC2, SES)

About the project: Framework for managing unit and UI tests in Continuous Integration (CI).

Responsibilities:

Designed backend architecture and database schema
Integrated open-source frameworks for virtual device test execution
Managed backend and frontend deployments

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