Ruslan Petrenko

Фрилансер

Backend Developer (Node.js / PostgreSQL)

Бишкек, Киргизия

Backend Developer (Node.js / PostgreSQL)

I build backends on Node.js (Express, Nest.js) with PostgreSQL as the primary database. Before freelancing, I spent six years on a mid-size SaaS product team, so I'm used to thinking not just about how to build a feature but how that feature will behave at ten times the user load. I design database schemas with normalization where it's genuinely needed and deliberate denormalization where it speeds up frequent queries. I write migrations that can be rolled back and try not to break API backward compatibility without versioning. I set up basic authentication, task queues, and integrations with external payment and email services. Most recently I've been deep in slow-SQL-query optimization and indexing — a service I can provide even without touching the rest of the system. I don't do frontend work beyond simple plain-HTML admin panels — for a real client-facing interface I recommend a separate frontend developer. Before starting, I ask for a spec or at least a 20–30 minute call, so the estimate is realistic instead of a guess.

Backend Developer (Node.js / PostgreSQL)

Навички

Node.jsPostgreSQLExpressNest.jsREST APIDatabase migrationsQuery optimization

Портфоліо

API for a booking service

Backend — A Node.js/Express REST API for a booking service — endpoints for creating, changing, and canceling bookings with time-overlap checks.

Database schema for a CRM module

Database — Designed PostgreSQL schema for an internal CRM module — clients, deals, interaction history, with indexes for frequent filters.

Query optimization for a reporting module

Database optimization — Sped up slow aggregate queries in a reporting module using materialized views and composite indexes.

Backend for a real estate inquiry service

Backend — An API for accepting and filtering property viewing requests, with role-based access control for agents.