Lazar Popović, Developer in Podgorica, Podgorica Municipality, Montenegro
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Lazar Popović

Verified Expert  in Engineering

Mobile Developer

Podgorica, Podgorica Municipality, Montenegro
Toptal Member Since
October 21, 2019

Lazar is an experienced web developer with over seven years in designing, developing, and deploying web apps. He is proficient in React, Python, and various libraries. He is well-versed in custom UI and API integration. Lazar has excellent problem-solving, debugging, and testing skills and is keen to stay current with industry trends and advancements in tech.


React, Django, Python, JavaScript, TypeScript, FastAPI, SQL
Mitec d.o.o
Kotlin, Bluetooth, Android, Android Jetpack, Firebase, GraphQL...
Airmeet Inc.
Android, Java, APIs, SQLite, Kotlin, Android Studio, Asynchronous Programming...




Preferred Environment

Git, Visual Studio Code (VS Code), React, Python, Django, FastAPI

The most amazing...

...thing I've worked on is the back end for Šansabet—the leading sports bookmakers in Montenegro.

Work Experience

Senior Full-stack Developer

2022 - 2023
  • Developed and implemented a data integration system that merged marketing data from various sources on the back end.
  • Developed and implemented diverse data visualization methods, including graphs, tables, and CSV formats.
  • Implemented multiple APIs and incorporated best UI practices, streamlining client management across multiple platforms.
  • Designed a client-centric self-invoicing system that greatly simplified financial tracking for enhanced client convenience.
  • Managed task assignments and bug tracking through Jira, efficiently coordinating task deliveries to other team members.
Technologies: React, Django, Python, JavaScript, TypeScript, FastAPI, SQL

Senior Android Developer

2021 - 2022
Mitec d.o.o
  • Created an Android app to communicate with a Bluetooth-connected watch that measures heart rate and oxygen level inside a patient's blood.
  • Processed byte data received from the device and transformed the data into usable Kotlin classes.
  • Made the login/register flow, syncing data with the server. Enabled the back end to control the device through the Android app.
  • Reverse-engineered Bluetooth SDK to see the messages sent from the device on the binary level.
Technologies: Kotlin, Bluetooth, Android, Android Jetpack, Firebase, GraphQL, Mobile Development, REST

Senior Android Developer

2020 - 2021
Airmeet Inc.
  • Started an app from scratch as a sole developer, setup the paradigm and coding guidelines for developers that joined afterward.
  • Developed a framework for building UI based on finite state machines.
  • Reviewed code through Bitbucket pull requests and ensured the quality was on par.
Technologies: Android, Java, APIs, SQLite, Kotlin, Android Studio, Asynchronous Programming, Coroutines, Android Jetpack, Functional Programming, Jira, Retrofit 2, Android Architecture Components, KOIN, Mobile Development, REST, Location Services and Maps, Stripe

Android Mobile App Developer

2020 - 2020
OTR Perfomance Inc
  • Used the client's Bluetooth SDK to connect to the IoT device.
  • Developed UI for the Android app, a bridge between servers and an IoT device that the client manufactured.
  • Connected the dots by implementing a REST API to transmit relevant Bluetooth data.
Technologies: Java, Android, iOS, AWS IoT, Bluetooth, Swift, Internet of Things (IoT), Android Studio, Asynchronous Programming, Room, Jira, Retrofit 2, Mobile Development, REST

Full-stack Developer

2015 - 2019
  • Designed and built applications for the Android platform from scratch.
  • Worked on back-end services in Node.js and related technologies.
  • Served as a senior developer and ensured the performance and responsiveness of applications.
  • Checked and ensured code quality and designed paradigms for writing Android apps.
  • Defined, designed, and shipped new features in multiple Android applications.
Technologies: Node.js, Android, SQLite, Android Studio, MongoDB, JavaScript, Express.js, Retrofit 2, Passport.js, Mobile Development, REST

Full-stack Developer

2013 - 2015
Bild Studio
  • Developed in-house apps as well as solutions for numerous clients.
  • Started as an Android developer but advanced to a full-stack developer position during the project.
  • Developed SDKs that were used across Android applications.
Technologies: Node.js, Android, SQLite, Android Studio, JavaScript, Express.js, Retrofit 2, Mobile Development, REST

Senior Android Developer
An interesting app that allows users to join virtual conferences with multiple speakers, tables, and QA sessions. I started the app as a sole developer, and later two more developers joined. I used Kotlin exclusively and all the latest available libraries to set up a robust codebase that other devs could jump on easily.

Mobile App Developer | Android
This was an IoT kind of app. The client had a device that was Bluetooth-based, and it would be attached to a truck and connected to the driver's mobile device. The office team used this setup to monitor their trucks remotely and deal with any issues that could arise. I used their in-house SDK for Bluetooth connection. My responsibilities were building the UI and consuming the data that the device generated to be passed on to company servers.

mCard (Fleka — Android)

mCard is a free service within an existing mobile banking app. It is available to all banking customers who are using Android mobile devices and have active Mastercard payment cards.

The payment process via mCard service is done simply by selecting the desired card first and then the payment option. After that, the user is asked to enter their PIN for the mobile banking app and finally to approach the POS terminal screen to establish the NFC connection, necessary to perform the transaction.

Dream Estates (Fleka — Node.js)

Dream Estates is a progressive technological platform for renowned real-estate agencies to sell properties on the Montenegrin and Croatian Coast. It is adapted to contemporary buyers’ needs.

I developed the API at the level of the entire platform for the purpose of managing properties whose characteristics are presented in detail—from location and description to photo gallery.

In addition, I built a newsletter subscription feature in the system and linked it to a Mailchimp external service.

NET Friends (Fleka — Android)

NET Friends is a mobile application designed for the UNICEF office in Montenegro and their ongoing campaign aimed at fighting and prevention of online violence against children as well as bullying among children.

The app is intended for children from the ages of nine to 11, and it is formed as a quiz with multiple choice answers.

Šansa Bookmakers (Bild Studio — Node.js)

This project was developed for “Šansabet,” one of the leading sports bookmakers in Montenegro.

It included a website with strong back-end support as well as an iOS app. My responsibilities were on the back-end side, where I used Node.js as a primary tool and MongoDB for the database.

Autodiler (Freelance — Android)

I worked on this app from scratch as a personal project for, a leading platform for selling/buying vehicles and parts. This was one of the first apps that I developed.


Kotlin, Java, JavaScript, SQL, Python, TypeScript, Swift, GraphQL


Express.js, Dagger 2, KOIN, Django


Node.js, Android Architecture Components, Retrofit 2, Passport.js, Stripe, React


Git, Android Jetpack, Mongoose, Android Studio, Jira


Functional Programming, Model View Viewmodel (MVVM), Asynchronous Programming, Test-driven Development (TDD), Mobile Development, REST


Android, Firebase, Visual Studio Code (VS Code), AWS IoT, iOS


MongoDB, SQLite


Room, Coroutines, Location Services and Maps, FastAPI, Bluetooth, Internet of Things (IoT), APIs

2009 - 2013

Bachelor's Degree in Computer Science

Mediterranean University - Podgorica, Montenegro

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