Yevhen

Yevhen PROFILE

Omelianenko Backend engineer specialising in payment and settlement systems. Sole
owner of the settlement core of a production crypto-to-fiat OTC platform
since May 2025 — schema and migrations on live data, idempotency and
Backend Engineer locking design, custody and fiat-rail integrations, and incident response — on
(Python) money paths where correctness under concurrency is the primary
engineering constraint.
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PROFESSIONAL EXPERIENCE
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Backend Engineer (Python)
Kyiv Emirex
LinkedIn 09/2024 – present | Remote
Platform ownership
GitHub Sole developer of the core payment API, owned end to end since 05/2025 —
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90+ REST endpoints, 38-table PostgreSQL schema, 62 migrations, ten async
workers; 93% of ~83k lines across 212 modules, alongside one engineer
SKILLS owning internal services.
Money correctness and concurrency
Languages: Designed a ten-pass ledger reconciliation engine, idempotent by
Python 3.11–3.13, SQL
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construction: diffs every money leg against already-written entries and self-
Backend: heals gaps each cycle without operator intervention.
FastAPI, Starlette, Pydantic v2, REST API Built exactly-once payout semantics — partner-supplied idempotency keys
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design and versioning, JWT auth, per- enforced by unique constraints, plus PostgreSQL advisory locks with
tenant authorisation, asyncio, aiohttp, conditional-UPDATE guards serialising concurrent balance mutations
httpx under READ COMMITTED.
Root-caused and closed five production money-loss paths, including a
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Databases: cross-tenant fund-misrouting defect traced to a custody provider's tenant-
PostgreSQL — schema design, raw SQL, wide reference uniqueness; every fix was structural rather than a retry.
hand-written migrations, advisory locks, Integrations
SELECT FOR UPDATE, ON CONFLICT Integrated five external money rails (MPC custody over gRPC,
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upserts, indexing, asyncpg and psycopg2 AED/EUR/USD payouts, RUB deposits, partner settlement, bank webhooks)
pooling and four FX providers, gated by per-company feature flags and a merchant
→ category → company → default config cascade.
Distributed / reliability: Replaced the incumbent custody provider end to end — gRPC client, per-
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Redis Streams with consumer groups and company vault routing, signing callbacks, on-chain verification — with no
XAUTOCLAIM, idempotency keys, retry partner-visible downtime.
and backoff strategies, circuit breakers, Built signed outbound webhooks (HMAC-SHA256, SSRF allowlist, staged
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signed webhooks (HMAC-SHA256), SSRF retry ladder that never retries 4xx) and a scrubbed outbound-provider audit
hardening, fail-closed design trail over Redis Streams.
Data and reliability
Domain: Migrated the primary datastore from Google Sheets to PostgreSQL on a live
Payment settlement, double-entry-style
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money system across 45 incremental phases, removing 17,000 net lines of
ledgers and reconciliation, FX rate Python with no data-loss incident.
resolution, EVM / Tron / Solana RPC, MPC Built the platform's earlier data plumbing: PDF bank-statement extraction
custody, sanctions screening and
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into a unified schema, incremental multi-coin exchange transaction
transaction risk scoring tracking with deduplication, and automated settlement reporting.
Infrastructure: Founded the test suite from zero (pytest, pytest-asyncio, 635 tests),
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Docker, Docker Compose, gRPC / protobuf, introduced structured logging with a 53-class domain error taxonomy, and
Git, GitLab CI, Linux and Windows authored nine partner-facing API references.
deployment Technologies: Python, FastAPI, PostgreSQL, Redis Streams, asyncpg,
Pydantic v2, Docker Compose, gRPC/protobuf, Web3, pytest
Testing:
pytest, pytest-asyncio, unit / service / API- Data Engineer
contract layers FERM
05/2024 – 08/2024 | Kyiv, Ukraine
English: Built automated collection pipelines extracting and normalising product
Advanced
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data from catalogues, websites, Excel and PDF sources into a unified
schema.
EDUCATION Developed a price monitoring service with Scrapy and Selenium, integrated
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with tender platforms for competitive procurement analysis.
MSc, Marine Engineering
Produced reporting and visualisation for business stakeholders in Power BI
Kherson State Maritime Academy
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and Matplotlib.
09/2019 – 12/2020
Python Developer
BSc (Honours), Marine Engineering Self-employed
Kherson State Maritime Academy 11/2023 – 05/2024 | Kyiv, Ukraine
09/2015 – 06/2019 Delivered data processing and automation tooling for multiple clients.
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Built web scraping solutions for collection at scale.
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