Johan – React, Python, Microsoft Azure, experts in Lemon.io

Johan

From Finland (UTC+3)flag

Full-stack Web Developer|Senior

Johan – React, Python, Microsoft Azure

Johan is a senior full-stack engineer with strong expertise in React, TypeScript, Python, and Azure. He has led architecture and infrastructure projects, including cloud migrations and regulated medical device software, and demonstrates sound judgment in system design and delivery. Feedback highlights his clear communication, business-oriented decision-making, and disciplined AI-assisted development practices. He is best suited for roles emphasizing architecture, infrastructure, and scoped ownership rather than rapid hands-on coding.

11 years of commercial experience in
Adtech
Advertising
AI
Consumer goods
Consumer services
Healthtech
Logistics
Medtech
Scientific research
Sports
Chatbots
Mobile apps
SaaS
Main technologies
React
5 years
Python
7.5 years
Microsoft Azure
2 years
Typescript
5 years
Additional skills
AI agent development
RAG
C++
FastAPI
JavaScript
PHP
MongoDB
LLM
Computer Vision
CI/CD
Node.js
Direct hire
Possible
Ready to get matched with vetted developers fast?
Let’s get started today!

Experience Highlights

Senior Software Engineer & Consultant
Feb 2026 - Ongoing6 months
Project Overview

Led a high-impact migration project for a food delivery platform, focusing on porting and adapting advertising technology components to a new platform. The project involved modernizing existing adtech functionality and ensuring a smooth transition to the new technical environment.

Responsibilities:
  • Acted as DRI for the migration of legacy services to the new brand-shared platform;
  • Discovered and fixed an incident-level bug that had been in production for years;
  • Identified and documented critical data parity issues, proactively coordinated with partner teams to prevent major launch delays;
  • Accelerated delivery by contributing core code and actively dismantling cross-team engineering bottlenecks.
Project Tech stack:
Golang
gRPC
Python
Claude Code
Lead Software Developer
Oct 2024 - Jul 20261 year 8 months
Project Overview

A PWA-based web application for planning, logging, and analyzing sports training. The platform supported individual athletes, self-coached paying users, professional coaches using SaaS features, and internal coaching teams, providing tools for structured training management and performance analysis.

Responsibilities:
  • Migrated 10+ years of production data to managed cloud infrastructure;
  • Rapidly ported .NET MVC app to a modern TypeScript (Bun) + React stack, using an AI-assisted workflow;
  • Engineered an agentic AI assistant utilizing OpenAI API and Azure AI Foundry, enabling autonomous tool execution and retrieval of proprietary business knowledge;
  • Optimized cloud service usage, reducing infrastructure costs by 53%.
Project Tech stack:
Microsoft Azure
Typescript
React
MySQL
Node.js
CI
CD
ETL
Bun.js
Hono.js
tRPC
GitHub Actions
AI-assisted coding
OpenAI API
Lead Developer
Sep 2024 - Feb 20261 year 5 months
Project Overview

An in-house web application for managing sports and fitness coaching. The platform combined training management, nutrition tracking, and direct communication between coaches and clients through an integrated chat.

Responsibilities:
  • Designed and provisioned a production cloud-native environment;
  • Built CI/CD pipelines and observability infrastructure;
  • Led an international engineering team;
  • Developed backend and mobile features;
  • Executed Python-based ETL for a major version upgrade.
Project Tech stack:
Golang
Svelte.js
Typescript
Capacitor
OpenAPI
PostgreSQL
Python
ETL
GitHub Actions
DevOps
Amazon S3
Docker
R&D & Software Engineer
May 2015 - Feb 20248 years 9 months
Project Overview

A diagnostic medical device for reading and analyzing lateral flow tests, covering the full product lifecycle from initial design through development. The project followed IEC 62304 and ISO 13485 requirements for regulated in-vitro diagnostic solutions.

Responsibilities:
  • Owned architecture across backend, frontend, and analytics;
  • Designed and implemented an integrated software and hardware solution;
  • Developed Python-based analytics workflows using NumPy and Pandas;
  • Delivered a production-grade system under strict regulatory requirements.
Project Tech stack:
Python
Typescript
React
Node.js
NumPy
Pandas
OpenCV
Computer Vision
GitLab CI
CD
Mobile Developer & Computer Vision Engineer
Jun 2017 - Oct 20203 years 4 months
Project Overview

Developed native Android and iOS applications integrating custom computer vision algorithms with cloud-based data visualization. The platform enabled users to process visual data and access insights through interactive visualizations.

Responsibilities:
  • Built a native Android application utilizing computer vision technology with Java and the Android SDK;
  • Ported the application to iOS, implementing an Objective-C++ bridging layer to enable the Swift frontend to utilize the native OpenCV C++ library;
  • Developed a reliable image processing pipeline through extensive data exploration and analysis of a large image dataset;
  • Implemented a cloud backend and database to collect telemetry and visualize results on an interactive world map.
Project Tech stack:
Computer Vision
Android
iOS
Java
Swift
Objective C

Education

2017
Physics
Master of Science - MS

Languages

Finnish
Advanced
Swedish
Advanced
English
Advanced

Hire Johan 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.