Lion Code logo Lion Code

$ whoami
// you tell, I code

Software engineering, from idea to App Store.

I'm Nikola Čubelić, the engineer behind Lion Code. For 13+ years I've been designing and shipping software - iOS apps first and foremost, plus the web applications and backends around them.

See my work Get in touch
01 - About

One engineer, full ownership.

Nikola Čubelić

Lion Code is me - Nikola Čubelić, a software engineer from Zagreb, Croatia. When you work with Lion Code, you talk directly to the person who designs, writes and ships your software. No hand-offs, no account managers, no telephone game.

My strongest ground is iOS and Swift - I've been building for Apple platforms since 2014 and my own apps live on the App Store today. Around mobile, I build what a product actually needs: web frontends in Next.js, backends in Django and Java, and the integrations that hold it all together.

I care about software that survives contact with real users: clean architecture, honest estimates, and code the next engineer can read. Away from the keyboard you'll find me on a bicycle, behind a drum kit, or chasing my kids around.

  • 13+ yrs experience
  • iOS · Swift · SwiftUI
  • Next.js · Django
  • Zagreb, Croatia 🇭🇷
02 - Services

What I do

From a napkin sketch to a maintained product. I take on complete projects or join your team where the deep platform experience is missing.

.swift

iOS & Mobile Development

Native iPhone and iPad apps in Swift and SwiftUI - architecture, App Store delivery, and everything in between. This is my home turf.

.tsx

Web Applications

Modern web frontends and dashboards in Next.js and React - often the companion piece to a mobile product.

.api

Backend & Integrations

REST APIs and business logic in Django and Java, payment integrations (SEPA), and the plumbing between your systems.

.consult

Consulting & Support

Technical consulting, code reviews and architecture guidance - plus long-term support for everything I ship. I don't disappear after launch.

03 - Selected work

Things I've built

A selection of shipped products - my own apps on the App Store and client work across mobile, web and backend.

SmartBox Organizer

own product

Storage box organizer for garage, home and moving. Number your boxes, search contents instantly, generate QR labels. Local-first with iCloud sync.

  • iOS
  • Swift
  • App Store
smartboxorganizer.app →

FoodSafe

client work

Digital food safety compliance for the hospitality industry - replaces paperwork with smartphone workflows, wireless sensors and cloud sync. In production since 2017.

  • iOS
  • Swift

Genius

client work

iOS development on Genius, InterCapital's robo-advisor: automated ETF portfolio investing for everyday people, from a 50 EUR minimum.

  • iOS
  • Swift
  • Fintech
geniusapp.com →

Konzum klik

client work

iOS app for online grocery shopping at Konzum, Croatia's largest retail chain: browsing, cart and ordering for everyday shoppers at scale.

  • iOS
  • Swift

Icarus SMS

client work

Aviation Safety and Compliance Management System - safety reporting and compliance workflows for aviation operators, on iPhone and iPad.

  • iOS
  • iPadOS

Ledolu

client work

Transportation management software - full-stack build with a Next.js frontend and a Django REST backend.

  • Next.js
  • Django REST

OJT Logbook

client work

Web application for keeping on-the-job training records: logging sessions, tracking progress, and reporting.

  • Laravel
  • Vue.js

Irki Webshop

own product

Custom-built webshop for the Irki brand, with a companion iOS admin app for managing orders on the go.

  • Web
  • iOS
  • Swift
irki.hr →

Emanuel Concert Ticketing

client work

End-to-end ticketing for a limited edition concert by the band Emanuel: generated, numbered, print-ready tickets, each with a unique QR code, plus scanner apps at the door. Tickets scanned after the show revealed a one-off hidden message.

  • Ticketing
  • QR
  • Print

MIDI Confetti Cannon

stage tech

An air cannon for confetti, triggered straight from the band's MIDI session: the blast lands exactly on the drop, every show, no stagehand required.

  • MIDI
  • Hardware

Meat Curing Chamber

hardware + iOS

ESP32-based controller for a meat curing (drying) chamber, paired with an iOS app over Bluetooth LE for monitoring and control.

  • iOS
  • BLE
  • ESP32

Plavi telefon

client work

Call center management software for the Plavi telefon helpline: call tracking, statistics and reporting for the people answering the phones.

  • Next.js
  • Web

Barcoder

open source

PDF417 barcode generator for SEPA payment slips in Swift - scan-to-pay barcodes straight from your iOS app.

  • Swift
  • Open source
View on GitHub →
04 - Clients

Trusted by

Companies and teams I've built software for or with, over the years.

Emanuel MIB Studio NEO Recycling Mali Einstein Plavi telefon Exelisso Q software Drvostipan
06 - Writing

From the blog

Notes from real projects - Swift, architecture and the occasional payments rabbit hole.

Generating PDF417 barcodes for SEPA payments in Swift

What I learned building Barcoder: the HUB3 payment slip format, and how to render a scannable barcode on iOS.

The Coordinator pattern in Swift, without the ceremony

How I untangle navigation from view controllers using coordinators - with a working tab bar example.
07 - Contact

Let's build something.

Have a project in mind, need an extra pair of experienced hands, or just want a second opinion on your architecture? Send a message - I reply personally, usually within a day.