An engineer who likes to see things through

Architecture, performance, and reliability — that's what gets me to work.

ДД

Daniil Davydov

Backend Developer

LocationRussia, remote
Experience2 years 7 months
EmploymentFull-time / part-time / internship
FormatRemote / hybrid
Message on Telegram

I'm a backend developer with 2.5+ years of commercial experience designing, building, and optimizing distributed server systems in Python (FastAPI) and PHP (Yii2).

I've worked in a 10-person product team and led a full-cycle solo project — from architecture to production: SoulMates, a high-load dating platform with ML-based matching, real-time chat, and asynchronous data processing.

Architecture & design

Designing REST APIs following Clean Architecture, SOLID, and the Repository Pattern. Experience decomposing monoliths and extracting resource-heavy services (ML, integrations) into isolated modules.

Performance & highload

Eliminating performance bottlenecks: fixing N+1 queries, optimizing algorithms, profiling, and resolving deadlocks in DB transactions. Designing multi-layer caching schemes (in-memory + disk).

Async processing & queues

Building event-driven systems on RabbitMQ + Celery. Configuring fault-tolerant message delivery (idempotency, retry policies), managing background workers, and monitoring queues via Flower.

Testing & QA

Building automated test infrastructure: unit tests, integration tests with rollback-isolated DB transactions, E2E (Playwright), and load testing (Locust).

Infrastructure & DevOps

Containerizing and orchestrating environments (Docker, Docker Compose), basic Kubernetes experience. Configuring Nginx and automating CI/CD pipelines (GitHub Actions).

Professional journey

2 years 7 months of commercial development — from a solo product to a product team.

June 2025 — present · 1 yr 2 mo

Backend Developer

POWER International-TIRES · team of 6 backend, 4 frontend engineers
  • Built a module to detect a service center's timezone and local time from coordinates; reworked the algorithm for a 4× speedup (65.1s → 14.8s).
  • Modernized the order-creation flow (cart, notes, service statuses) and user profile functionality.
  • Implemented an API-key system for direct client API access; found and fixed 5 critical route-hanging bugs inside DB transactions.
  • Fixed an email encoding bug (UTF-8) that caused some emails to be sent incorrectly; optimized N+1 queries in transactions.
  • Wrote integration tests for 50+ API routes, fully covering the order lifecycle, plus unit tests for business logic.
  • Authored technical documentation for service logic and maintained Postman collections, reducing onboarding time for new developers.
PHPYii2MS SQLRedisDockerSentry
January 2024 — June 2025 · 1 yr 6 mo

Backend Developer

SoulMates · full-cycle solo project
  • Designed a scalable architecture based on the Repository Pattern; extracted resource-heavy ML algorithms into an isolated FastAPI service.
  • Configured rate-limiting and secure authentication via httpOnly JWT.
  • Eliminated N+1 issues in candidate recommendation calculations by moving to batch queries with data preloading; implemented two-tier caching (in-memory + disk).
  • Moved email delivery to an async queue (RabbitMQ + Celery) with retry policies and Flower monitoring — API now responds instantly.
  • Integrated a recommendation engine based on LightGBM (16 features, including Jaccard similarity of interests); implemented MMR diversification and an ELO rating for cold start.
  • Built a 6-layer privacy protection system: EXIF stripping on photos, geo-coordinate fuzzing, contact filtering before a match, and photo verification.
  • Built test infrastructure: E2E (Playwright), load testing (Locust), integration tests via httpx.AsyncClient with rollback-isolated DB state; set up CI/CD in GitHub Actions.
PythonFastAPIPostgreSQLRabbitMQCeleryLightGBMDocker Compose

Learning & growth

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Secondary education

Continuous self-education: distributed systems architecture, highload, and ML engineering — learned through real product work.