Олександр

Oleksandr Bunin
Python Developer
Kyiv
[open contact info](look above in the "contact info" section) | [open contact info](look above in the "contact info" section) | https://t.me/i_am_oleksandr192

Summary
Senior Backend Software Engineer with 8+ years of commercial experience in Python and Java, specializing
in scalable distributed systems, AI-powered SaaS platforms, and high-load microservices architectures.
Python is the primary production stack — used across FastAPI services, AI agent workflows (LangGraph),
ETL pipelines, Telegram automation (Telethon), and end-to-end testing infrastructure.
Complementary production experience includes Java/Spring Boot (enterprise-grade microservices),
Golang/Gin (2+ years), and Node.js/Nest.js (2+ years). Solid frontend exposure in React and Next.js enables
full product ownership without frontend dependency.
Founder and Lead Engineer of multiple live products, including an AI orchestration platform aggregating 40+
models, a BI analytics pipeline, and a subscription-based media platform.

Key Achievements
› 8+ years delivering production backend systems in enterprise and startup environments
› Designed multi-tenant SaaS architectures serving thousands of users with strict tenant isolation and
transactional event handling
› Implemented AI agent workflows using LangGraph for multi-step reasoning, tool execution, and
streaming responses
› Built real-time systems at scale: WebSocket and SSE-based pipelines, live updates, multi-client state
sync
› Led backend architecture in enterprise SAP ecosystems with Kafka-based event-driven infrastructure
› Built Python ETL pipelines integrating Meta Ads, TikTok Ads, and Moloco Ads APIs — saving 20+
hours/week of manual reporting
› Built privacy-first developer tools achieving 5K+ monthly organic visitors and 100/100 Lighthouse scores
› Maintained 99.9% uptime across all production environments
› Achieved <100ms conversion event latency with 99.8% delivery rate on a real-time event pipeline
handling 10K+ events/day

Technical Skills

Backend
› Python (8+ years): FastAPI, async APIs, Celery, background workers, AI agents, LangGraph, Telethon,
Telegram Bot API
› Java (8+ years): Spring Boot, Spring Security, Spring Modulith, Hibernate, JPA, MyBatis
› Golang (2+ years): Gin, GORM
› Node.js (2+ years): Nest.js, Express.js
› REST APIs, WebSockets, Server-Sent Events (SSE), event-driven architecture
› Kafka, RabbitMQ, Redis
› OAuth2, OIDC
AI & Automation
› LangGraph — multi-step agent workflows, tool execution, streaming
› Multi-model orchestration (LLM, image, video)
› Telegram automation — Telethon, Bot API, multi-account management
› Prompt engineering, RAG pipelines, AI SaaS architecture

Databases & DevOps
› PostgreSQL, MySQL, MongoDB, SQLite, SAP HANA Cloud, Neo4j
› Docker, Kubernetes, Helm, Terraform
› GitHub Actions, Jenkins, Bamboo
› ELK Stack, Nginx, HAProxy, S3-compatible storage
› Linux administration (Ubuntu/Debian), SSL/TLS automation (Let's Encrypt)

Architecture Patterns
› Microservices and modular monoliths
› Event-driven architecture (Kafka, Redis Pub/Sub)
› Async-first APIs (SSE, WebSockets, background workers)
› CQRS, SAGA, Outbox patterns
› Multi-tenant SaaS (logical and schema-level isolation)
› Caching strategies (Redis) for performance and cost optimization
› High-availability, zero-downtime deployments

Analytics & Data Engineering
› ETL pipeline development (Python)
› Meta Ads Conversion API, TikTok Events API, Moloco Ads API
› Data warehousing, incremental sync, change detection
› BI dashboards and automated reporting

Frontend (Supporting)
› React, Next.js (App Router, SSR, RSC, Streaming)
› TypeScript — sufficient for full product ownership without frontend dependency

Professional Experience

LeverX International LLC — Senior Software Engineer (Backend / Full-Stack)
Apr 2018 – Present

› Developed and maintained Java (Spring Boot) and Python microservices: business logic, REST APIs,
integration layers, performance tuning, and production operations
› Implemented event-driven flows with Kafka: producers, consumers, message handling, and
troubleshooting in distributed systems
› Built real-time features via WebSockets: connection lifecycle, server-side handling, multi-client state sync
› Owned Python E2E test suites, backend unit/integration tests, and release regression verification
 › Designed and maintained database schema migrations (PostgreSQL / SAP HANA Cloud) using ORM +
migration tooling
› Supported cloud-native delivery: Kubernetes (Helm), CI/CD pipelines, rollout debugging, and production
operations
› Participated in epic-level architecture planning, code reviews, and cross-team technical alignment

FSM SAP — Field Service Management Platform
Apr 2021 – Jun 2024
Large-scale multi-tenant platform for assigning tasks to thousands of field technicians, optimizing resource
utilization across tasks, skills, equipment, and schedules.

› Implemented features across Java/Spring Boot microservices with tenant-aware data isolation
› Applied transactional event publishing patterns to prevent data inconsistency and message loss
› Implemented and maintained Kafka-based inter-service communication (producers, consumers,
troubleshooting)
› Built and maintained Python E2E test infrastructure and backend integration tests
› Contributed to WebSocket-based real-time UX updates
› Supported Kubernetes deployments (Helm), rollout verification, and production troubleshooting
› Built shared libraries and internal tooling used by multiple teams

Technologies: Java 11/17, Spring Boot, Python (E2E testing), Kafka, PostgreSQL, Kubernetes, Terraform,
Helm, Bamboo, WebSockets, SAP BTP

SAP Deal Modeling Tool (DMT) — Senior Backend / Full-Stack Engineer
High-performance deal modeling platform enabling Account Executives to evaluate complex multi-scenario
enterprise deals (TCV, ACV, LEP, IT1/IT2).

› Built and extended backend services (Java/Spring Boot) and domain logic for deal modeling and KPI
calculations
› Implemented caching strategies (Redis) to reduce price list access latency during active modeling
sessions
› Implemented real-time collaboration via WebSockets: state broadcasting and synchronized multi-client
sessions
› Integrated with SAP Harmony (CPQ) and multiple legacy internal SAP systems
› Worked within SAP BTP Cloud Foundry runtime with platform-managed security and resilience

Technologies: Java, Spring Boot, Spring Modulith, SAP HANA Cloud, Hibernate, Liquibase, Redis, SAP
Event Mesh, SAP BTP (Cloud Foundry)

Multitenant Task Manager — Utility Companies Platform
Jul 2020 – Nov 2020
Enterprise task management platform with multi-tenant architecture for utility companies.

› Designed and implemented backend architecture decisions
› Implemented security with Spring Security: authentication, authorization, exception handling
› Built real-time features using Spring WebSockets and JMS (ActiveMQ)

Technologies: Java 11, Spring 5.0 (Security, MVC), Hibernate, JMS (ActiveMQ), WebSockets, MongoDB,
MySQL

Financial Applications — Product Companies
Jan 2020 – Jun 2020
Suite of financial applications handling invoices, orders, and payments.
 › Implemented backend modules for Invoices, Authentication, Registration, Orders, and Payments
› Designed database schema and optimized SQL queries

Technologies: Java 8, Spring 3.0, Hibernate, PostgreSQL

Microsoft Visio to BPMN Converter
Dec 2020 – Jan 2021

› Designed architecture and implemented parsing algorithm for Visio -> BPMN 2.0 conversion

Technologies: Java 11, Camunda BPMN 2.0 API, Apache POI OOXML, Spring MVC

Online Education Platform
May 2019 – Dec 2019

› Implemented REST APIs and optimized SQL queries on SAP Cloud Platform

Technologies: Java 8, Spring Boot, MyBatis, SAP Cloud Platform

Founder Experience & Products

Promtheon — Unified AI Workspace (SaaS)
Founder & Lead Engineer | promtheon.io
AI-powered SaaS platform providing a unified workspace for interacting with 40+ LLM, image, and video
models.

› Designed and built backend architecture for AI orchestration and multi-model routing
› Implemented AI agent workflows using LangGraph for multi-step reasoning and tool execution
› Built real-time streaming using Server-Sent Events (SSE)
› Developed scalable FastAPI services for chat, document processing, and AI tools
› Implemented caching and performance optimizations for cost and latency control
› Deployed on cloud infrastructure with Docker containerization
› Owned end-to-end product lifecycle: architecture, development, deployment, and operations

Technologies: Python (FastAPI, LangGraph), Golang (Gin), PostgreSQL, Redis, Docker, Cloudflare

Telegram Browser Client with Marketing Attribution
Lead Engineer
Browser-based Telegram client with real-time event streaming to advertising platforms for conversion
tracking.

› Built backend services in Python for Telegram API integration and event processing
› Implemented Meta Ads Conversion API (server-side) and TikTok Events API integration
› Built event pipeline for streaming conversion events to ad platforms in real-time
› Achieved 99.8% event delivery rate with retry mechanisms and <100ms latency
› Scaled to handle 10K+ events/day

Technologies: Python, Golang (Gin), Next.js, SSE -> WebSockets, Meta Ads Conversion API, TikTok Events
API, Docker

BI Analytics Pipeline — Multi-Platform Ad Data Integration
Lead Engineer
Automated ETL pipeline extracting, transforming, and loading advertising data from multiple platforms into a
centralized BI system.
 › Built Python ETL pipelines for Meta Ads API, TikTok Ads API, and Moloco Ads API
› Implemented incremental sync with change detection for efficient processing
› Designed data warehouse schema for multi-platform campaign analytics
› Built alerting system for campaign anomalies and budget threshold breaches
› Scheduled sync jobs using cron and Python background workers
› Saved 20+ hours/week of manual reporting work
› Maintained 99.9% data accuracy with validation checks

Technologies: Python (FastAPI), PostgreSQL, Redis, Meta Ads API, TikTok Ads API, Moloco Ads API,
Docker

Papira — Subscription-Based Media Platform
Founder & Lead Engineer | papira.net.ua

› Built backend-first subscription media platform
› Configured Nginx for reverse proxy and SSL termination
› Managed Linux server with security hardening, monitoring, and automated SSL renewal
› Achieved sub-500ms page load times and 99.9% uptime

Technologies: Golang (Gin), PostgreSQL, Nginx, Linux (Ubuntu), Docker, Cloudflare

Telegram Automation & Bots
› Built Telegram bots and automation clients using Python, FastAPI, Telethon, Telegram Bot API, and
LangGraph
› Implemented AI-powered conversation management and multi-step agent workflows
› Automated message handling, routing, multi-account management, and alerting

Technologies: Python, FastAPI, Telethon, Telegram Bot API, LangGraph, PostgreSQL

Education

Bachelor of Science in Applied Mathematics
Applied Cryptography & Information Security
Polytechnic Institute, Physical-Technical Institute

Languages
› English — Advanced (C1)
› Ukrainian — Native