Azzaro Mujic, Developer in Zagreb, Croatia
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Azzaro Mujic

Verified Expert  in Engineering

iOS Developer

Zagreb, Croatia
Toptal Member Since
February 25, 2019

Azzaro is an experienced software engineer with a decade of expertise in product-oriented development. He excels in crafting innovative native iOS and Android apps and aligns business objectives with technology to maximize impact. He is skilled in leadership, programming, algorithms, cost estimations, process optimization, code review/testing, architectural design, issue resolution, strategic planning, client management, quality assurance, and project management. He delivers exceptional value.


Google API, Swift, Firebase, Lottie, iOS Frameworks, UIKit, Mobile Apps
Petersons (via Speck)
RxSwift, Model View ViewModel (MVVM), JSONAPI::Resources, Core Data, Swift...
Sumeru Software Solutions Pvt Ltd
Realm, Objective-C, Audio Streaming, Video Streaming, WebRTC...




Preferred Environment

Charles, Zeplin, Sketch, Xcode, Git, MacOS

The most amazing...

...thing I’ve done was build a dream team—highly motivated and satisfied—where the client ended up happy and all of the deadlines were met.

Work Experience

Freelance Lead iOS Developer

2020 - 2021
  • Developed a platform for those who enjoy life's simplest joys while being organized and productive.
  • Implemented multiple sign-in features with Google, email, Apple, and phone.
  • Worked in an agile team with four iOS developers, four Android developers, one designer, and one project manager.
  • Led an iOS team of four, which included direct reports to me.
  • Coached and reviewed the performance of the whole agile team.
Technologies: Google API, Swift, Firebase, Lottie, iOS Frameworks, UIKit, Mobile Apps

Freelance Lead iOS Developer

2019 - 2020
Petersons (via Speck)
  • Developed an educational iOS application using MVVM architecture with RxSwift.
  • Implemented an offline mode feature using core data and data synchronization.
  • Worked in an agile team followed by scrum principles.
  • Developed a white-label application so it can be used by multiple clients.
  • Led the iOS team with a focus on architecture and clean code.
Technologies: RxSwift, Model View ViewModel (MVVM), JSONAPI::Resources, Core Data, Swift, Lottie, iOS Frameworks, UIKit, Mobile Apps

Freelance Lead Senior iOS Developer

2019 - 2020
Sumeru Software Solutions Pvt Ltd
  • Developed real-time communication using VoIP, including audio and video streaming.
  • Worked on a messenger feature with more than one million users. Used the Realm database to store messages.
  • Implemented SSO for a mobile app so that the app can authenticate into multiple external web pages.
  • Implemented webhooks so the app can pay instead of using an external web.
  • Coached and reviewed the performance of the engineering team.
  • Led the iOS team with a focus on architecture and clean code.
Technologies: Realm, Objective-C, Audio Streaming, Video Streaming, WebRTC, Real-time Communication (RTC), WebKit, VoIP, Webhooks, Swift, Agile Software Development, Lottie, Google Maps SDK, iOS Frameworks, UIKit, Mobile Apps

Freelance iOS Expert

2019 - 2020
Peg B Technology
  • Reviewed the project requirements and defined the development architecture.
  • Led recruitment efforts and conducted interviews to hire talented developers.
  • Mentored and evaluated employees' technical skills. Onboarded new developers.
  • Conducted routine code reviews and ensured code quality and collaboration.
  • Created an iOS payment app, delivering a seamless mobile payment experience.
Technologies: iOS, Google Maps SDK, iOS Frameworks, UIKit, Core ML, Mobile Apps

Head of Mobile Development

2019 - 2020
  • Supervised efficient workflows within the company and ensured compliance with company policies and regulations.
  • Designed strategic plans to provide effective product development.
  • Ensured appropriate implementation of all methodologies and development processes.
  • Facilitated interviews to hire appropriate employees and provided training to achieve all organizational goals.
  • Coordinated with the R&D department and prepared plans for effectively integrating various technical skills.
  • Led a mobile department with more than 20 people to achieve the highest technical goals.
Technologies: Pushwoosh, Messenger, R&D, Java, Objective-C, Kotlin, Swift, Bluetooth, Google Maps, Facebook iOS SDK, Figma, Sketch, Minimum Viable Product (MVP), Model View Presenter (MVP), Model View ViewModel (MVVM), Clean Code, Clean Architecture, VIPER Architecture, Viper, JSONAPI::Resources, API Documentation, Agile Software Development, Android, iOS, Google Maps SDK, iOS Frameworks, UIKit, Core ML, 3D Graphics, Metal, iOS SceneKit, Augmented Reality (AR), 3D Modeling, Mobile Apps

iOS Senior Developer and Team Leader

2017 - 2019
  • Successfully led a 10+ member team and drove collaboration.
  • Efficiently organized meetings and scrums for seamless communication.
  • Monitored and reported on standards and performance targets.
  • Played a key role in recruiting new staff and building a strong team.
  • Effectively coordinated daily work allocation, optimizing productivity.
  • Improved the business and development processes inside the company.
  • Communicated closely with the client for consulting purposes.
  • Implemented continuous integration with GitLab and Fastlane.
  • Provided valuable guidance and mentorship to junior developers, fostering growth.
  • Reviewed the project requirements and defined the development architecture.
Technologies: Android, iOS, iOS Frameworks, Mobile Apps

iOS Senior Developer

2016 - 2017
  • Developed the most popular Croatian application for advertising.
  • Worked in an agile environment with scrum principles.
  • Worked closely with designers to ensure iOS design best practices.
  • Collaborated with back-end developers and helped to define RESTful APIs for mobile applications.
  • Performed regular code reviews and peer programming.
  • Wrote iOS development-related blog posts and gave talks at iOS meetups.
  • Mentored junior iOS developers. Wrote onboarding documents and made the process better for new developers.
Technologies: CI/CD Pipelines, GitLab CI/CD, Apple Maps API, Google Maps, Machine Learning, ML Kit, PaintCode, Zeplin, Sketch, Clean Architecture, VIPER Architecture, Viper, RxSwift, Core Data, Objective-C, AsyncDisplayKit, CocoaPods, Swift, iOS

iOS Developer

2015 - 2016
  • Built multiple iOS apps with an emphasis on good UI/UX.
  • Developed various iOS apps written in Swift and Objective-C using MVC, MVVM, or VIPER architecture.
  • Meticulously crafted a bespoke user interface (UI) that exudes attention to detail. Every aspect, from the layout to the animations, has been thoughtfully designed to ensure a seamless and engaging user experience.
  • Defined and implemented an offline mode for the app.
  • Wrote unit and UI tests to ensure the stability of the written code.
  • Performed routine code reviews to ensure code quality and facilitate collaboration.
Technologies: iOS, Swift, Objective-C, Agile, Scrum, SnapKit, Google Maps

DAZN | Live and On-demand Sports Streaming
As a senior iOS developer at DAZN, I had the opportunity to work on exciting projects. We followed clean architecture principles and utilized technologies like RxSwift for reactive programming. Unit testing, snapshot testing, and Gherkin UI tests were integral to our development process, ensuring high-quality code and seamless user experiences. I specifically contributed to developing watch party and streaming features, enhancing the platform's capabilities, and enriching user interactions. It was an engaging experience to be part of a team dedicated to delivering top-notch sports streaming services at DAZN.

White-label Food Ordering App

As the senior developer on the Koala project, I led the development of a white-label food ordering app. We created a robust and scalable solution by leveraging the MVVM+Coordinator architectural pattern and RxSwift framework. Our development process included extensive unit and snapshot testing to ensure the app's functionality and maintain code quality.

Working closely with our client based in New York, we integrated famous food brands such as Mod Pizza, Capriotti's, and Waba Grill into the app. Users could easily browse menus, customize orders, and place food orders from their favorite restaurants within the app.

The Koala app provided a seamless and intuitive user experience, allowing customers to track their orders in real-time and receive timely notifications. The app also facilitated secure online payments, ensuring a convenient and safe transaction process.

Adopting modern development practices and technologies, we delivered a high-quality white-label food ordering app tailored to our client's requirements.

Njuskalo is Croatia's largest online trading place, where millions of sellers and buyers publish ads daily, review bids, and successfully trade. More than 1 million active ads and more than 200,000 active users exist.

With the Njuskalo application, you can:
• Submit and manage ads
• Search and browse ads
• Save interesting ads
• Save queries with filters
• Modify user data
• Pay funds on balance (card, PayPal, Paysafe, SMS)
• View accounts and traffic
• Push ads to the top of the list using the "Jump to Top" feature

My initial role in this project was as an iOS developer, and I became the team leader and scrum master after one year.

We Vibe App
While at We-Vibe, I worked on developing the We-Vibe app, available on the App Store. I leveraged cutting-edge technologies like Combine and dependency injection while following clean architecture principles. Thorough unit testing ensured the app's stability and reliability. A significant highlight was implementing a video chat feature with custom controls, allowing users to grant permission to their partners and control their toys via WiFi and Bluetooth. It was an exciting and fulfilling experience to contribute to enhancing intimate connections through innovative mobile technology.

Elyments | Social Media Simplified
Elyments is a comprehensive social networking app that is literally a one-stop app for everything you might need: Connect and converse with friends, share updates, network with like-minded people, discover interests, make seamless voice and video calls, and much more. The app has more than one million downloads and half-million daily active users.

The app is written in Swift using MVVM architecture with Coordinator.

My role was to improve architecture, educate others, improve processes, and make things work.

A1 Telecom
I was an iOS expert for these features of the app:
• Monitor balance and optimize costs
• Top-up and pay on the go
• Manage services and update packages
• Control the rest of the traffic, minutes, and SMS
• View accruals for the current period
• Enable or disable additional services
• Change the tariff plan
• Top-up with A1 banking
• Find your nearest A1 office
• Find out about A1's best deals first

Aircash | Mobile Money Transfer App
Financial application for money remittance between people and for topping up or withdraw money from an online partner and telecom accounts.

The iOS app is written in Swift. It uses the MVVM architecture pattern and a reactive approach (RxSwift).

Unit tests are written using Quick/Nimble frameworks. In addition to the unit, the app also has a suite of snapshot tests.

The app is hosted on a GitLab repository and uses GitLab integrated CI and CD features.

Takko | Video-sharing App

As an iOS developer for a startup based in California, I had the opportunity to work on a short-form mobile video app similar to TikTok. I was responsible for implementing key features that enhanced user engagement. This included developing a seamless video feed with immediate playback of short-form videos, allowing users to dive into captivating content effortlessly. I also worked on creating a feature-rich video creation tool that empowered users to add text, music and apply effects like the popular boomerang effect. Being part of a California-based startup increased my excitement as a vibrant and innovative tech scene surrounded me. It was a rewarding experience to contribute to the dynamic world of short-form video creation and be part of a team revolutionizing social media engagement.


Taskkey is a task management application. It's a platform for those who enjoy life's simplest joys while being organized and productive. So, have a "deadline to catch" for that marketing pitch? Assign and manage your tasks like a champ! Or want to throw a "surprise birthday party" for a loved one/your friend? Just create a card and start planning the most amazing party in town!

The app is written in Swift using MVVM architecture. The back end is written in Firebase; all data is encrypted.

My role was to improve architecture, educate others, improve processes, and push the app to the App Store before a hard deadline.

I was the team leader and iOS developer for the FOREO app that connects users' phones with skincare devices to make their skin gorgeous and glowy.

Features allowed users to:
• Connect and manage FOREO skincare devices via Bluetooth
• Receive tutorial treatments on the phone
• Shop within the app


This comprehensive iOS app simplifies a truck driver's daily search for parking by providing information about facilities on European highways. With Trucker, users can see where parking spaces are available, what facilities are included with each parking space, and where parking a truck is safe.

The app is written in Swift using VIPER architecture and clean code. The code is tested using unit tests (Quick and Nimble) and UI tests.

The app includes amazing custom animations and transitions.

Meddox Healthcare Mobile App
As the senior iOS developer and team leader for the Meddox app, I spearheaded the development of a comprehensive healthcare solution. My responsibilities included unit testing to ensure the app's stability.

Meddox featured an impressive AI-powered photo recognition capability, enabling users to scan and digitize their medical records effortlessly. The app securely stored the recognized data alongside the original images.
Additionally, Meddox included a calendar feature to help users manage medical appointments and medications. With a focus on data security, I implemented robust measures such as encryption and secure authentication.

Collaborating with designers, I ensured a seamless user interface and experience. Leading the development process and meeting deadlines, I facilitated an efficient workflow. In summary, I successfully led the team in creating Meddox, a healthcare app that securely stores medical records, and leverages AI for photo recognition, integrates a calendar, and prioritizes user privacy.

OASC Academic Skills Training | Educational Mobile App
OASC Academic Skills Training is an educational mobile app for military students.

The app is written in Swift. It uses the MVVM architecture pattern and a reactive approach (RxSwift). It has an offline mode implemented with core data. It uses the JSON:API standard for communication with the back end.

I led a team of two. We aimed to write clean, testable code and deliver a great UI/UX product. I had daily meetings where we communicated with the back-end team, a designer, the Android team, and the client.

Alias Words
As the creator and owner of a popular game on both the App Store and the Google Play Store, I designed an exciting and engaging player experience. The game's objective is simple yet challenging: explain as many words as possible to your teammates within a limited time frame. This encourages quick thinking, effective communication, and teamwork. The game provides a platform for players to showcase their creativity and strategic skills while having a blast with friends or family. With its availability on both major app platforms, the game has reached a broad audience, fostering a sense of competition and enjoyment among players worldwide.

Pasta Maestro

Pasta Maestro is an iOS application for pasta lovers. This app is packed with surprising step-by-step recipes, videos, and inspirational stories to help pasta lovers cook a varied Italian meal in no time.

The app is written in Objective-C using VIPER architecture.

I aimed to build an iOS app for iPhone and iPad that supports portrait and landscape orientation. The app also includes an offline mode built with the Core Data framework. I have worked in a team of two.

iVictim is an educational iOS app that is vulnerable. Its main goal is to provide a platform for mobile security enthusiasts, professionals, and students to test their iOS penetration testing skills in a legal environment.

It includes:
- Bad login
- Piracy detection
- Jailbreak detection
- Screenshot vulnerability
- Pasteboard vulnerability
- SSL pinning
- Transport layer security
- Web view vulnerability
- Brute force
- Local storage vulnerability

Blog Post: So You Think You Can Call Yourself a “Senior iOS Developer”?

If you search for an iOS developer on LinkedIn, you will see job titles prefixed with the word "senior". But what does it mean to be a "senior developer" and, more precisely, what does it mean to be a "senior iOS developer"?

Blog Post: Animations as a Part of Your Daily Job

Good design is one of the most important aspects of mobile applications. It's valuable for end-users, defines how the application looks and feels, and defines how the application works.

However, it is not enough to only have a good design in your applications for the perfect UX/UI. Nowadays we have to take one step forward and make animations a part of UX/UI. In my opinion, every mobile application should contain animations.

Blog Post: Getting Deeper With Deep Linking on iOS

If you have a website that allows users to access some of the same content and functionality as your app, this post is for you. As of iOS9, it is possible to connect websites and iOS apps using universal links. In other words, when users click on an HTTP/HTTPS link on an iPhone or iPad they will be redirected to an iOS app.
2013 - 2016

Master's Degree in Computer Science

University of Zagreb, Faculty of Electrical Engineering and Computing - Zagreb, Croatia

2010 - 2013

Bachelor's Degree in Computer Science

University of Zagreb, Faculty of Electrical Engineering and Computing - Zagreb, Croatia

MARCH 2017 - MARCH 2019

Scrum Master

Scrum Alliance


Social Media APIs, JSON API, Core Animation, CocoaPods, RxSwift, Google Maps SDK, Lottie-iOS, Twilio API, Xcode Server, Facebook iOS SDK, Parse SDK, Camera API, WebRTC, Google API, Firebase iOS SDK, Apple Maps API, JSONAPI::Resources, Google Maps, SnapKit, Pushwoosh, RxCocoa


Auto Layout, Xcode, Git, GitHub, GitLab, GitLab CI/CD, AsyncDisplayKit, Charles, Charles Proxy, SourceTree, Fastlane, Figma, PaintCode, Sketch, Zeplin, Optimizely, Jira, CircleCI


Core Data, Viper, iOS Frameworks, SwiftUI, RealmSwift, UIKit, ARKit, Core ML, iOS SceneKit, OAuth 2, Core Motion, Vapor, iOS SDK, Core Bluetooth, Combine, Metal


Swift, Objective-C, Kotlin, C++, Swift 3, Java, SQL, HTML


API Architecture, Agile Software Development, Mobile Development, Waterfall Development, REST, Unit Testing, VIPER Architecture, Agile, Scrum, Clean Architecture, Clean Code, Model View Presenter (MVP), Model View ViewModel (MVVM)


iOS, Firebase, Twilio, Android, Parse, Apple TV, Apple Watch, MacOS, tvOS


Firebase Realtime Database, Realm, JSON, SQLite

Industry Expertise

Social Media, Project Management


Video Streaming, Code Architecture, CI/CD Pipelines, Social Media Apps, Social Media Login, Mobile UI, Mobile UX, Mobile Video, Architecture, iOS Design Guidelines, Leadership, Team Leadership, iOS Animations, Bluetooth, iOS Camera, Live Chat, Lottie, Social Networks, Mobile Apps, Videos, Audio Streaming, Estimations, iOS App Design, iPad, Product Management, Business Analysis, Scrum Master, Certified ScrumMaster (CSM), API Documentation, Communication, Empathy, Planning, QA Automation, GitFlow, Security, Augmented Reality (AR), 3D Modeling, Webhooks, VoIP, Real-time Communication (RTC), Crypto, 3D Secure, 3D Scanning, ML Kit, Messenger, Push Notifications, Writing & Editing, Blogging, Deep Linking, Minimum Viable Product (MVP), R&D, Machine Learning, Driving, iPhone, Mobile Security, UX Analysis, Quality Assurance (QA), UI Testing, WebKit, Networking, Broadcasting, TV Broadcasting, Streaming, HTTP Live Streaming (HLS), Over-the-top Content (OTT), iOS Video, iOS TV, TV, Multicast, 3D Graphics

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