Олег

OLEH NOVOSELSKYI
Full Stack Python Developer | Django · FastAPI · React · TypeScript
Lviv, Ukraine (Remote) | [відкрити контакти](див. вище в блоці «контактна інформація») | [відкрити контакти](див. вище в блоці «контактна інформація») | [відкрити контакти](див. вище в блоці «контактна інформація»)

SUMMARY
Full Stack Python Developer with 2.5 years of commercial experience, focused on building production Python services with Django / DRF
and FastAPI, backed by PostgreSQL, Redis, and Celery, with React / TypeScript and React Native on the client. Experienced in REST API
and data-model design, OAuth 2.0 / JWT / RBAC, background jobs, real-time (WebSockets / Channels), payments (Stripe, Moyasar), and
third-party integrations, shipping to production with Docker, GitLab CI/CD, pytest, and Sentry. Owns features end-to-end and works
directly with clients.

EXPERIENCE
Full Stack Developer (Python) — Join.To.IT Jul 2025 – Present
Backend-focused full-stack development on outsourced products for US and EU clients, owning features end-to-end across the full
delivery cycle.
ARRA — referral network for luxury real estate agents (US client) | Python, Django, DRF, Celery, Channels, PostgreSQL, Stripe, React
• Developed backend and full-stack features on a Django / DRF platform serving a React web app and an Expo mobile client through
one API, collaborating directly with the US client on production incidents, fixes, and new features.
• Engineered the matching and introductions flow: an approved match opens a shared WebSocket chat (Django Channels) seeded
with a system “ARRA introduction” message, with admin-approved scheduling driven by Celery / Redis.
• Resolved duplicate match-reminder notifications caused by Celery redelivering long-ETA tasks by implementing an atomic claim
(UPDATE … WHERE sent_at IS NULL) so each reminder fires exactly once, and cleaned up the duplicates already in production.
• Diagnosed and fixed a signup outage where a lint auto-fix had removed Django signal imports, leaving new members without a
profile: traced the root cause, restored signal registration, and backfilled affected users on production.
• Integrated Stripe subscriptions and promo codes with SendGrid list sync, SimpleJWT sliding sessions with rotating refresh tokens,
and multi-channel notifications (in-app, Expo push, email, SMS via Twilio), releasing to dev and prod with Docker Compose and
GitLab.
EWRA — multi-tenant risk-assessment SaaS (EU/UK/US) | Python, Django, DRF, PostgreSQL
• Worked on a configurable compliance platform with per-product billing, independent access periods and Report-Credit batches,
organization identity locking, and jurisdiction-driven (EUR/GBP/USD) applicability rules.
• Contributed to Super-Admin configuration, role-based access, audit trails, and CSV/XLSX billing exports over a Django REST
backend.
Flight Logbook — offline-first logbook & analytics platform for pilots | Python, FastAPI, PostgreSQL, Redis, React Native
• Designed and implemented the Python / FastAPI backend and PostgreSQL schema for flights, aircraft, and a 10,000+ airport
directory, with Pydantic validation and API versioning.
• Built timestamp-based delta sync (push/pull endpoints with conflict resolution) and an offline-first React Native client on
WatermelonDB, keeping a pilot's logbook consistent across devices with no connection.
• Wrote the import pipeline for ACARS logs, photo OCR, and uploads (parsing, deduplication, validation), cutting manual flight entry
by ~60%; added a PDF report service for regulator-compliant logbooks.
APOK — cleaning-operations platform (Saudi market) | Python, Django, DRF, Celery, Redis, React Native
• One of two backend developers; owned payments and the driver-facing API across three client apps (Customer, Worker, Driver).
• Integrated the Moyasar gateway (Apple/Google/Samsung Pay, Visa/Mastercard, STC Pay) and Tabby/Tamara BNPL with payment
creation, webhook signature verification, and idempotent order-status updates; moved reconciliation and notifications into Celery
tasks.
• Built driver job-assignment, route, and location endpoints; verified Firebase phone-auth tokens server-side; delivered RTL (Arabic)
support on the Driver React Native app.

Full Stack Developer — Appexoft May 2024 – Jun 2025
Built frontend and backend features for a production marketplace, collaborating cross-functionally with designers, backend engineers,
and QA.
Delivery Platform — multi-vendor courier & restaurant marketplace | Python/Django, Node.js, Socket.IO, PostgreSQL, React
• Built two synchronized apps around a shared order lifecycle, connecting customers, restaurants, and couriers from order creation
through to delivery.
• Developed real-time order-status synchronization over Socket.IO rooms, propagating state changes across both apps and the
backend in under 2 seconds.
• Implemented courier-location ingestion and ETA calculation with the Google Maps / Places APIs, plus live route visualization on an
interactive map.
• Built the React / TypeScript restaurant panel (incoming orders, menus, live courier map), cutting map re-renders by ~40% with
marker clustering and memoization on mid-range Android devices.
• Integrated FCM push notifications for new orders and every status change, and maintained the GitLab CI/CD release pipeline.

SKILLS
Languages: Python, TypeScript, JavaScript (ES6+), SQL

Backend: Django, Django REST Framework, FastAPI, Celery, Django Channels, Node.js, Express, Pydantic, REST API design, WebSockets
/ Socket.IO
Databases & Caching: PostgreSQL, Redis, AWS S3
Frontend: React, TypeScript, Redux Toolkit, React Query, Vite; React Native (Expo), offline-first, WatermelonDB
Auth & Security: OAuth 2.0, JWT (SimpleJWT), RBAC, DRF permissions, Firebase Auth, webhook signature verification
Integrations: Stripe, Moyasar (Apple/Google/Samsung Pay, Tabby, Tamara), SendGrid, Twilio, Google Maps / Places, LLM APIs, OCR
DevOps & Testing: Docker, Docker Compose, GitLab CI/CD, Traefik, Git, GitHub, pytest, Jest, Sentry, Postman

EDUCATION
B.Sc. Computer Science — Lviv Polytechnic National University 2023 – 2027 (expected)

LANGUAGES
English — B2 | Ukrainian — Native