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Mark – Python, Flask, FastAPI, experts in Lemon.io

Mark

From Poland

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Back-end Web DeveloperSenior
9 years of commercial experience
AI
Machine learning
Platforms
Video streaming software
Web development

Mark – Python, Flask, FastAPI

Meet Mark, a Senior Backend Engineer with 5+ years of experience building high-performance systems in Python. He’s an expert in async frameworks like aiohttp and FastAPI, with deep knowledge of PostgreSQL, Redis, and AWS. Mark has led the development of scalable, event-driven architectures and owns the full stack — from infrastructure (Docker, Kubernetes, Terraform) to CI/CD and testing.

Certified in AWS and experienced in mentoring and candidate evaluation, Mark is proactive, detail-oriented, and thrives in fast-paced, cross-functional teams. He's ready to deliver impact from day one.

Main technologies
Python
8 years
Flask
2 years
FastAPI
4 years
Additional skills
Ansible
Kubernetes
Docker
Machine learning
AWS
SQLAlchemy
Jenkins
Grafana
AWS Lambda
Amazon RDS
Sentry
Amazon S3
Amazon SQS
Terraform
CloudWatch
AWS SES
Amazon SNS
PostgreSQL
Redshift
MQTT
DynamoDB
WebRTC
Pydantic
pytest
Selenium
Rewards and achievements
Tech interviewer
Direct hire
Possible
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Experience Highlights

Senior Software Engineer
Dec 2020 - Ongoing4 years 6 months
Project Overview

Video streaming platform that allows cameras to stream video over WebRTC. Main features include live view and video playback with an event management system over MQTT.

Responsibilities:
  • Designed and developed from scratch backend for a streaming project as a solo backend engineer;
  • Full ownership of the product - backend, infrastructure and simple frontend for demo;
Project Tech stack:
Python
FastAPI
asyncio
Pydantic
SQLAlchemy
Alembic
IoT
MQTT
DynamoDB
Amazon ECS
WebRTC
AWS Lambda
Terraform
Software Engineer
Feb 2019 - Dec 20245 years 10 months
Project Overview

Platform that allows data operators to annotate video and bunch of other stuff. 10+ services under our team ownership with active feature development and maintenance. Some of them are high-load with RPS reaching 200,000+ during peaks.

Business need: a lot labeled data needed for ML models to train based on it and show better results in production. Service also has an API that allows ML engineers to operate with the data.

Responsibilities:
  • Developed and took under ownership 10+ services with active feature development and maintenance;
  • Implemented services for data annotation task management (admin, queues, complex business logic for annotation), event management, authentication and authorization, annotation jobs workers, feature flags management, etc.;
  • Conducted zero-downtime replication of 300+ millions of records from PostgreSQL to Redshift;
  • Achieved 8x performance for a service to handle 100,000+ RPS by identifying bottlenecks, refining system architecture and implementing targeted optimizations;
  • Conducted technical spikes and proof-of-concepts (POCs) to evaluate solutions and improve decision-making for complex engineering tasks;
  • Mentored engineers by guiding them through technical challenges, fostering best practices;
  • 90%+ tests coverage including unit and integration tests.
Project Tech stack:
Python
AWS
PostgreSQL
Redshift
FastAPI
Aiohttp
Amazon ECS
Amazon SQS
Amazon SNS
AWS Lambda
SQLAlchemy
Amazon RDS
Kubernetes
Amazon S3
API Gateway
asyncio
Terraform
AWS SES
Grafana
CloudWatch
Web Workers
API testing
Sentry
Senior QA Engineer
Nov 2018 - Aug 20198 months
Project Overview

The company serves the growing business need for full oversight and management of applied AI.

Responsibilities:
  • Developed a test automation framework for a web-based platform using Selenium and Python, ensuring a scalable and reliable testing process;
  • Designed and executed automation scripts, including smoke and regression tests, for both front-end and back-end systems with reporting tools;
  • Configured automated test executions in CI, streamlining continuous integration for efficient testing cycles;
  • Utilized container technologies to support scalable, containerized testing environments;
  • Reported and verified bugs, contributing to improved product quality and effective issue resolution.
Project Tech stack:
Python
pytest
Selenium
Docker
Jenkins

Education

2018
Computer Science
Bachelor

Languages

Ukrainian
Advanced
English
Advanced

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