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

Mark

From Poland (UTC+2)flag

Back-end Web Developer|Senior

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.

9 years of commercial experience in
AI
Fintech
IoT
Machine learning
Smart home
Platforms
Video streaming software
Web development
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
ElasticSearch
Golang
GitLab CI/CD
Kafka
Redis
gRPC
Protobuf
Rewards and achievements
Tech interviewer
Direct hire
Possible
Ready to get matched with vetted developers fast?
Let’s get started today!

Experience Highlights

Senior Software Engineer
Jul 2025 - Aug 20261 year 1 month
Project Overview

Designed and evolved core services powering a high-scale payment infrastructure, including the API gateway, Webhooks delivery, Public API, Massive operations Service, Search service and many more. Part of Platform / DevEx team with a main goal of improving development velocity while having ownership on the most critical services that served as the primary entry point for all customer traffic and internal integrations, requiring high availability, low latency and strict reliability guarantees.

Responsibilities:
  • Owned and evolved the API Gateway service — the single entry point for all public traffic — ensuring high availability, low latency and 99.99% SLO.
  • Built and maintained the Webhook service, reliably delivering real-time event notifications to clients at scale with guaranteed delivery semantics with a scale of 300+ million events.
  • Designed and shipped the Mass Ops service, enabling engineering and merchant operations teams to implement workflows execution using Temporal — reducing per-team integration effort.
  • Improved organization-wide CI/CD performance by 40% through pipeline optimization, build parallelization and tooling improvements.
  • Led engineering adoption of AI-assisted development workflows, integrating MCP-powered tooling, Claude and CodeRabbit into the development lifecycle.
  • Collaborated with multiple engineering teams to define platform standards and improve operational excellence.
Project Tech stack:
Golang
gRPC
Protobuf
Amazon ECS
PostgreSQL
DynamoDB
Amazon SNS
Amazon SQS
Redis
Kafka
Terraform
GitLab CI
CD
ElasticSearch
Grafana
Senior Software Engineer (Greenfield)
Feb 2025 - Jul 20255 months
Project Overview

Greenfield project. Architected and built a cloud-native video streaming platform from scratch for smart camera devices. The system enabled live video streaming, motion-triggered recordings, event processing and cloud-to-device communication for large-scale IoT deployments.

Responsibilities:
  • Architected and built a WebRTC video streaming platform from scratch as sole backend engineer, delivering a production-ready system end-to-end.
  • Designed the video streaming supporting real-time viewing and recording workflows.
  • Designed and owned the events service, capturing motion and on-demand recording events with low-latency access patterns.
  • Took full ownership of cloud infrastructure (AWS, Terraform) — provisioning, scaling and maintaining all platform resources from day one.
Project Tech stack:
WebRTC
Golang
Python
DynamoDB
AWS Lambda
PostgreSQL
Terraform
FastAPI
Amazon ECS
MQTT
AWS
Aiohttp
Senior Software Engineer
Feb 2019 - Feb 20256 years
Project Overview

Built and scaled the core machine learning data platform used for training computer vision models powering Ring cameras and smart home devices. The platform supported video ingestion, annotation workflows, dataset generation, secure access management and AI-assisted labeling.

Responsibilities:
  • Designed, scaled and took under ownership 10+ platform's core video and annotation services supporting millions of training assets.
  • Built and scaled the core video & annotation service for ML data platform, achieving an 4× performance improvement by profiling bottlenecks and redesigning critical data access patterns to handle significant RPS.
  • Redesigned the dataset management service — reduced dataset generation time from 12 hours to 5–10 minutes by rearchitecting, enabling on-demand dataset creation across 300+ millions of filtered records.
  • Built a complete annotation ecosystem including task management, workflow orchestration, prioritization and quality controls — including AI model integration for automated blurring of sensitive/PII data, assisted ML annotation.
  • Designed and implemented Video Access Manager, a secure video access service built on RBAC using Open Policy Agent combined with Authorisation service, enforcing fine-grained access control at scale.
  • Contributed directly to improving Ring's ML models used across cameras and doorbells, with the platform serving as the primary data annotation pipeline for model training.
  • Collaborated with ML engineers, product managers and data scientists to accelerate model development and experimentation.
  • Mentored engineers and contributed to architecture decisions across multiple teams.
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
Python
FastAPI
Aiohttp
PostgreSQL
Amazon SQS
Amazon SNS
Redshift
AWS Lambda
Amazon S3
Terraform
AWS
Grafana
ElasticSearch
Redis

Education

2018
Computer Science
Bachelor

Languages

Ukrainian
Advanced
English
Advanced

Hire Mark or someone with similar qualifications in days
All developers are ready for interview and are are just waiting for your requestdream dev illustration
Copyright © 2026 lemon.io. All rights reserved.