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Backend Developer & Systems AdministratorBelgrade, RS

Velibor
Simonović

I build REST APIs and real-time services in TypeScript, Go and PHP, and run the Linux servers they're deployed on.

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open to work · Belgrade or remote

01 / About

I'm a backend developer and systems administrator in Belgrade. I build APIs, and then I run the servers they live on.

Since 2022 I've worked remotely with Hitex World Operations SA. I built the backend for Skycaster.tv, a versioned REST API that serves weather forecasts to TV and radio broadcasters, plus the headless pipeline that renders those forecasts to broadcast video.

On the infrastructure side I moved 33 sites, 35 mail domains and 45 databases off cPanel onto a self-managed HestiaCP server on Oracle Cloud, and I keep it patched, monitored and backed up. Alongside that I'm studying Information Systems and Technologies at FON.

“Make it work. Make it right. Make it fast. In that order.”
3+years in production
33sites on servers I run
267unit tests on one API

02 / Experience

Hitex World
Operations SA

Dec 2022 – Present · Remote

Three hats at one company: I build the APIs, run the servers they live on, and keep both secure and backed up.

  1. 01

    Backend Developer

    • Built the Skycaster.tv backend, a versioned REST API (TypeScript/Next.js) serving Open-Meteo forecasts to TV and radio broadcasters.
    • Added API-key auth, Redis rate limiting and Stripe billing, covered by 267 unit tests.
    • Built a headless, CLI-driven render pipeline (Electron, Chromium, FFmpeg) with SDI and MP4 output on macOS and Windows.
    • Packaged and code-signed the Skycaster macOS app (electron-builder, Apple Developer ID) with bundled FFmpeg and V8 bytecode protection.
  2. 02

    Server Administrator

    • Migrated hosting from cPanel/WHM (after 3 years) to self-managed HestiaCP on Oracle Cloud: 33 sites, 35 mail domains and 45 databases across 24 accounts.
    • Run nginx + Apache, PHP-FPM 8.1–8.3 and MariaDB 11.4, with Let's Encrypt SSL on 31 domains.
    • Run BIND DNS for 37 zones on custom nameservers (ns1/ns2.sxsful.com) and the mail stack: Exim via Brevo, Dovecot, SpamAssassin, ClamAV.
    • Fixed email deliverability by tracing bounces to unauthenticated WordPress senders and missing SPF/DKIM.
  3. 03

    Infrastructure Administrator

    • Hardened the server with 11 fail2ban jails (incl. custom rate-limit and scanner filters), a 15-rule firewall and automatic security updates.
    • Set up monitoring (New Relic, atop/sysstat, disk-usage alerts) and restic backups on a systemd timer with 14/6/6 retention.

03 / Stack

Backend

  • Go
  • TypeScript / Node.js
  • PHP / Laravel
  • REST APIs
  • WebSockets
  • Redis
  • MariaDB / MySQL
  • SQLite
  • Stripe API

Frontend & Apps

  • React / Next.js
  • React Native / Expo
  • Electron
  • Tailwind CSS

Infrastructure

  • Linux & Bash
  • nginx & Apache
  • HestiaCP / cPanel
  • Docker
  • Cloudflare
  • BIND DNS & mail
  • fail2ban & restic

04 / Projects

05 / Education

  • B.Sc. Information Systems and Technologies

    Oct 2024 – Oct 2028

    Faculty of Organizational Sciences (FON), Belgrade

    E-business Technologies concentration. Coursework: Web Technologies, Databases, Software Engineering.

  • High School Diploma, Natural Sciences and Mathematics

    Sep 2020 – Jun 2024

    Gymnasium “Bora Stanković”, Vranje

    Databases and SQL, computer networks, web programming, calculus, statistics, quantum and particle physics, astrophysics.

Languages

  • SerbianNative
  • EnglishFluent
  • GermanElementary
  • RussianElementary

06 / Contact

Got a
Problem?

An API that needs building, a server that needs migrating, or mail that keeps landing in spam? I'm listening.

Send me an email