Alex is available for hire
Hire AlexAlex Rossovsky
Verified Expert in Engineering
Python Developer
Bangkok, Thailand
Toptal member since December 1, 2021
Bio
Alex is an accomplished full-stack developer with a distinctive edge in computer security and reverse engineering. His expertise spans developing full-stack web applications and mobile applications for Android. Alex's strong problem-solving skills and diverse technical skillset ensure he delivers optimal solutions for even the most intricate challenges.
Portfolio
Cogentic Labs Inc.
Python, React, OpenAI API, Retrieval-augmented Generation (RAG), LangChain...
clozz.io
React, MacOS, Swift, Python, ChatGPT, ChatGPT API, Claude, CopilotKit, Chatbots...
TensorAlchemy
Python, PyTorch, Machine Learning Operations (MLOps)...
Experience
- Linux - 11 years
- Python - 10 years
- Reverse Engineering - 10 years
- Android - 10 years
- C - 9 years
- Full-stack - 8 years
- Django - 6 years
- Technical Leadership - 5 years
Preferred Environment
PyCharm, Vim Text Editor, Android Studio, VirtualBox, Interactive Disassembler (IDA), Server Security, Automation, Data Scraping, Claude Code
The most amazing...
...project I've worked on is mobile device management (MDM). It's a complex Django server and Android app solution to control 50,000+ devices.
Work Experience
Full-stack AI Engineer
2025 - PRESENT
Cogentic Labs Inc.
- Architected and developed full-stack AI-powered bid matching platform using Node.js, MongoDB, and React, deployed to DigitalOcean with a complete CI/CD pipeline implementation.
- Implemented an AI document parsing system using instructor.js for LLM orchestration and Zod for structured output validation, comparing top-tier and mini models across providers (GPT-4/3.5, Claude Opus/Haiku, Gemini Pro/Flash, Grok).
- Conducted comprehensive cost-benefit analysis of LLM models and vector store solutions (OpenAI, Ragie, Google Vertex AI vs In-House), providing data-driven recommendations that informed key architectural decisions.
- Designed complete software architecture in Miro, establishing system blueprints for back-end services, AI integration, and data flow across the platform.
- Built co-pilot chat functionality with persistent message storage and single-thread-per-opportunity architecture, integrating CopilotKit with defined RAG architecture and back-end actions, enabling users to extract useful data.
- Developed document scraping pipeline using Playwright with smart bot detection bypass (stealth and proxy), handling complex formats including zip files and image-based documents.
- Built front-end components in React based on Lovable-generated code, resolving front-end/back-end inconsistencies and API schema duplication issues.
- Led technical evaluation and selected Gemini 2.5 Flash as the most cost-effective model with sufficient quality for production parsing, transitioning the project from research phase to production build mode.
Technologies: Python, React, OpenAI API, Retrieval-augmented Generation (RAG), LangChain, REST APIs, Supabase, Prompt Engineering, FastAPI, Node.js, Large Language Models (LLMs), CopilotKit, MongoDB, BullMQ, Algorithms, AI Chatbots, Multistage LLM Chains, Scraping, Claude API, Software Architecture, Anthropic
CTO, Senior Full-stack Developer
2025 - 2025
clozz.io
- Built full-stack AI sales coach assistant using React and Python.
- Developed a MacOS client app with screen recording API to record calls done by sales managers.
- Created AI-based chatbot using CopilotKit React library.
- Developed back-end and data retrieval (RAG) endpoints for chatbot using FastAPI.
Technologies: React, MacOS, Swift, Python, ChatGPT, ChatGPT API, Claude, CopilotKit, Chatbots, AI Chatbots, FastAPI, Retrieval-augmented Generation (RAG), Slack, Scraping, Software Architecture
Senior Python Developer
2024 - 2024
TensorAlchemy
- Developed and optimized the FastAPI back end for a blockchain-based project, ensuring efficient API support and high performance.
- Deployed and fine-tuned machine learning models, including Stable Diffusion and ImageReward, enhancing model accuracy and relevance.
- Developed a Discord bot for human validation, integrating models for image generation evaluation to streamline user verification.
- Managed comprehensive DevOps tasks on Linux servers, covering database management, Grafana setup, and project metric monitoring, ensuring system reliability and uptime.
- Created a human evaluation system on Amazon MTurk for quality assessment of generated images, improving data quality and feedback accuracy.
Technologies: Python, PyTorch, Machine Learning Operations (MLOps), Artificial Intelligence (AI), Machine Learning, Stable Diffusion, DevOps, Linux, FastAPI, MongoDB, Grafana, Discord Bots, Discord, OpenAI, Claude, Technical Leadership, React, ChatGPT API, AI Chatbots, Scraping, Web Scraping, Software Architecture
Senior Python Developer
2023 - 2024
NEWO AI
- Defined a microservices architecture and developed an AI-based project.
- Integrated the ChatGPT Assistants API and a function-call API into company workflows.
- Developed AI-based browser automation using the Playwright Library.
- Managed and mentored a small team of back-end and front-end developers.
- Developed a back end using FastAPI, Python, PostgreSQL, and RabbitMQ.
Technologies: Docker, Kubernetes, FastAPI, Python, SQLAlchemy, ChatGPT, Artificial Intelligence (AI), Asynchronous Programming, Back-end Development, DevOps, Performance Optimization, CI/CD Pipelines, Database Design, Leadership, Containerization, OpenAI Assistants API, OpenAI, Prompt Engineering, Large Language Models (LLMs), API Integration, Technical Leadership, Grafana, React, ChatGPT API, AI Chatbots, Scraping, Web Scraping, Claude API, Software Architecture
Senior Full-stack Developer (via Toptal)
2023 - 2023
CREATE MEDIA S.R.L
- Developed an instance of ChatGPT, a clone with its own set of features, and integrated it with the company database.
- Created the project from scratch using Docker, FastAPI, SQLAlchemy, PostgreSQL, and React for the front end.
- Determined a set of OpenAI and other data analysis APIs for integration.
- Leveraged ChatGPT function that calls the API to give AI access to company sources of data: databasea, Excel sheets, Google Sheets, and websites via Playwright scripts. Developed a plugin system for each source.
- Developed a custom code interpreter plugin for automating company workflows when the CI plugin was not available.
- Made CI/CD using GitHub Actions to deploy projects to the cloud.
- Used LlamaIndex and ChatGPT to summarize and store company data.
Technologies: Docker, OpenAI GPT-4 API, Data Analysis, Algorithms, Reverse Engineering, Data Visualization, APIs, FastAPI, React, Cloud, LangChain, Chatbots, Artificial Intelligence (AI), Full-stack, Back-end, Git, OpenAI GPT-3 API, ChatGPT, Python, Asynchronous Programming, Back-end Development, DevOps, Performance Optimization, Database Design, Containerization, OpenAI Assistants API, OpenAI, Prompt Engineering, Large Language Models (LLMs), API Integration, ChatGPT API, Software Architecture
Senior Developer | Reverse Engineer
2023 - 2023
Rollee SaS
- Reverse-engineered an Android app obfuscated by a commercial tool, Promon.
- Recovered multiple obfuscated algorithms from native ARM code to Python.
- Researched API endpoints used by Android apps and created API clients in Python.
- Developed FastAPI microservices for remote device management.
Technologies: Mobile Apps, Reverse Engineering, APIs, Algorithms, Python, Documentation, ARM, ARM Assembler, Decompilation, Hex-Rays Decompiler, Android, Cryptography, Git, Back-end Development, API Integration, Scraping, Web Scraping, Software Architecture
Python Developer
2022 - 2022
Shippo
- Worked as part of a team to switch the whole company from Python 2 to Python 3.
- Fixed code for migrating to the newest Django and Python.
- Corrected CircleCI jobs to support the deployment process for the new Python 3 environment.
- Fixed many deployment issues related to Kubernetes cluster deployment and the new Python 3 environment.
- Created Python scripts to perform stress testing to measure the performance of the new Python 3 environment against Python 2.
- Developed scripts to identify blind points and bugs not covered by automatic tests.
Technologies: Python, Django, Kubernetes, Docker, Stress Testing, CircleCI, Android API, Cloud, Full-stack, Back-end, Git, Back-end Development, DevOps, Performance Optimization, CI/CD Pipelines, Database Design, Containerization, API Integration, Software Architecture
Senior Full-stack Flutter Developer
2021 - 2022
Nextsense
- Built an Android app that communicates with specific Bluetooth earbuds collecting data to derive insights about sleep, seizures, and other clinical cases.
- Developed the native part in Java and Flutter for UI (as a module over the native app).
- Created the back-end part in pure Python to act as a scheduler for time-critical push notifications and database manager.
- Converted multiple designed pages from Figma to Flutter.
- Developed an emulator that allowed to work on the UI part without having the actual device.
Technologies: Flutter, Cloud Firestore, Python, Docker, Android, Google Cloud Platform (GCP), SQL, Python 3, SSH, Cloud, Full-stack, Back-end, Git, Back-end Development, Containerization, API Integration, Software Architecture
Full-stack Flutter and Back-end Developer
2020 - 2021
Freelance
- Developed a Flutter app for a big dental company that helps users learn about their healing progress and interact with clinics.
- Built the back end for an app using Django framework and integration with the internal company database, 1C:Enterprise.
- Developed an admin panel for app-specific features such as interaction with the user via messages.
Technologies: Flutter, Android, iOS, Django, Python, REST APIs, PostgreSQL, Dart, Mobile, Architecture, Technical Leadership, Mobile Development, CSS, Bash, SQL, Python 3, Django REST Framework, SSH, Full-stack, Back-end, Git, Back-end Development, DevOps, Performance Optimization, Database Design, Containerization, API Integration
Full-stack Developer
2015 - 2021
Freelance
- Developed an MDM solution with full use of Android features and back end written in Python and Django.
- Made Windows-based software for a remote firmware update with the use of Qt framework with Django server as the back end.
- Built Android apps for different purposes based on customer requirements.
- Managed and deployed back-end software on multiple Linux servers at DigitalOcean with features for different customers.
- Reverse-engineered multiple Android and Windows applications and researched USB and TCP-based protocols using Wireshark.
- Managed a small team of back-end and Android developers.
Technologies: Java, Kotlin, Qt 4, C, Django, Python, DigitalOcean, Linux, REST APIs, Architecture, Mobile Development, HTML, CSS, Bash, WebView, SQL, Python 3, Django REST Framework, SSH, Cryptography, Full-stack, Back-end, Back-end Development, DevOps, API Integration, Amazon Web Services (AWS), Hex-Rays Decompiler
Full-stack Developer
2014 - 2015
Freelance
- Developed a front-end app using Backbone.js and Marionette and a back end using Yii PHP framework for a cinema production company.
- Managed the development process for both back end and mobile. Developed small parts of the iOS application.
- Developed architecture for offline synchronization between the iOS device and back end for customers with poor internet connection during the production process.
Technologies: JavaScript, PHP, Backbone.js, Yii, Linux, REST APIs, Architecture, Mobile Development, HTML, CSS, Bash, SQL, Python 3, SSH, Android API, Cryptography, Full-stack, Firmware, Back-end, Python, Back-end Development, Assembly, Low-level Programming
Reverse Engineer and Software Developer
2010 - 2014
Telecommunications Security Company
- Reverse-engineered C, ARM, and Java mobile apps with the help of IDA debugger.
- Researched and developed applications and baseband stack working with GSM protocol (3GPP specs). Developed baseband and Linux Kernel modules in pure C.
- Debugged apps using hardware debugger (JTAG) and worked with hardware and baseband processor DSP.
- Developed different apps for Android, using low-level libraries written in C.
Technologies: C, C++, ARM Embedded, Linux, Windows Mobile, Android, JTAG, Reverse Engineering, Mobile, Architecture, Mobile Development, CSS, Bash, WebView, Android API, Cryptography, Firmware, Back-end, Python, Performance Optimization, Database Design, Assembly, Low-level Programming
Full-stack Developer
2009 - 2012
Translation Agency
- Developed software for tracking orders, translators, customers, and payment calculations.
- Deployed the project as a Windows-based server using MAMP stack.
- Assured that the server worked at production for more than ten years, as the customers reported.
Technologies: JavaScript, Yii, PHP, MySQL, Architecture, HTML, CSS, Full-stack
Experience
Mobile Device Management Solution for Samsung Phones
MDM solution with full use of Android features and a back end written in Django (Python).
The solution consists of two main parts:
• The Django-based back end acts as a server for device enrollment, management of device policies, and remote application installation.
• The Android application, written in Java, is the client app for performing server-controlled actions and utilizing features of MDM (Samsung Knox)
The solution consists of two main parts:
• The Django-based back end acts as a server for device enrollment, management of device policies, and remote application installation.
• The Android application, written in Java, is the client app for performing server-controlled actions and utilizing features of MDM (Samsung Knox)
Dental Care Management App
https://astrejaapp.ruFull-stack Flutter and Django back-end app helping customers of a dental company to track their progress in healing, see their expenses, and communicate with clinic administration. The most challenging process was integrating the existing database and passing data into the Flutter app, which was solved by developing a middle service written in Django.
Firmware Flashing Solution
A remote software flashing tool used to update firmware on Qualcomm and MTK-based mobile phones and it consists of a Windows tool written in Qt 4 framework (C++) and Django back end (Python) to track software update states.
The Windows tool used low-level serial communication via com port and protocols acquired by reverse-engineering existing flashing tools (x86) and device software (ARM).
The Django back end was used to build and store different firmware depending on customer requirements. The firmware was then downloaded by Windows tool and flashed to phones.
The Windows tool used low-level serial communication via com port and protocols acquired by reverse-engineering existing flashing tools (x86) and device software (ARM).
The Django back end was used to build and store different firmware depending on customer requirements. The firmware was then downloaded by Windows tool and flashed to phones.
Smart Home Automation App
Worked on Flutter Android and iOS app for smart home automation system built on top of Home Assistant. Improved the existing system architecture and team development environment. Implemented integration for different kinds of smart home devices.
Brain Conditions Monitoring App
Developed an Android app with Flutter UI that communicates with a Bluetooth device to monitor and collect EEG data from the brain and notify users about different clinical studies. Developed the back end on Python to handle database-specific tasks and serve time-critical push notifications to users' smartphones.
Education
2006 - 2012
Engineer's Degree in Computer Science
Peter the Great St. Petersburg Polytechnic University - Saint Petersburg, Russia
Skills
Libraries/APIs
Android API, REST APIs, React, Playwright, OpenAI Assistants API, Claude API, Backbone.js, Vue, SQLAlchemy, PyTorch, OpenAI API, Node.js
Tools
Vim Text Editor, Git, Android Debug Bridge (adb), Claude Code, PyCharm, WebView, Figma, ChatGPT, Slack, Android Studio, VirtualBox, Interactive Disassembler (IDA), Celery, CircleCI, Grafana, Claude, CopilotKit
Languages
C, Python, Bash, JavaScript, C++, Java, Dart, CSS, HTML, Embedded C, SQL, Python 3, Assembly, PHP, Kotlin, ARM Assembler, TypeScript, Swift
Frameworks
Django, Qt, Flutter, Django REST Framework, Yii, Flask
Paradigms
Automation, Mobile Development, REST, Microservices, Asynchronous Programming, DevOps, Database Design, Stress Testing, Real-time Systems
Platforms
Linux, Android, Mobile, Embedded Linux, Docker, Firebase, Windows Mobile, DigitalOcean, iOS, Google Cloud Platform (GCP), Kubernetes, Amazon Web Services (AWS), MacOS
Storage
MySQL, PostgreSQL, Cloud Firestore, MongoDB
Other
Software Development, Reverse Engineering, APIs, Web Scraping, Architecture, Technical Leadership, SSH, Cryptography, Cloud, Chatbots, Full-stack Development, Full-stack, Firmware, Web Development, Back-end, Back-end Development, Proxies, API Integration, ChatGPT API, Scraping, Software Architecture, ARM Embedded, Qt 4, Wireless Protocols, Minimum Viable Product (MVP), Internet of Things (IoT), Embedded Systems, Embedded Development, Documentation, Telegram Bots, Data Scraping, OpenAI, OpenAI GPT-4 API, FastAPI, Artificial Intelligence (AI), Cloudflare, OpenAI GPT-3 API, Graphical User Interface (GUI), Browser Automation, Performance Optimization, Containerization, Prompt Engineering, Large Language Models (LLMs), AI Chatbots, Low-level Programming, Anthropic, Computer Security, JTAG, MDM, ARM, Mobile Apps, Algorithms, Decompilation, Hex-Rays Decompiler, Data Analysis, Data Visualization, LangChain, Server Security, CI/CD Pipelines, Leadership, Machine Learning Operations (MLOps), Machine Learning, Stable Diffusion, Discord Bots, Discord, Retrieval-augmented Generation (RAG), Supabase, BullMQ, Multistage LLM Chains
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