Tadej Slamic, Developer in Oslo, Norway
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Tadej Slamic

Verified Expert  in Engineering

Software Developer

Oslo, Norway
Toptal Member Since
July 10, 2019

With over a decade of experience in the software industry, Tadej boasts an exceptional track record. His versatile expertise ranges from assisting startups to guiding FTSE 100 companies through digital transformations, fueling the fintech revolution, optimizing particle accelerators, and more. Specializing in developing modern, scalable, high-performance solutions, Tadej also excels in team leadership, strategic business planning, and effective communication.


Go, Java, JavaScript, TypeScript, Python, GraphQL, Android, iOS, React...
Team Management, Technical Leadership, Leadership, Tech Sales, Public Speaking
Python, Node.js, React, TypeScript, Swift, Kotlin, Java, Docker, Kubernetes...




Preferred Environment

Go, Java, Kotlin, Python, JavaScript, TypeScript

The most amazing...

...project I've worked on went from zero to millions of users in less than a year and won an internationally acclaimed award for the best product in its genre.

Work Experience

Principal Consultant

2020 - PRESENT
  • Assisted a fintech startup in delivering a Minimum Viable Product (MVP), which led to a successful Series A funding round and earned the Non-Bank Lender of the Year award.
  • Collaborated with a multinational pharmaceutical and biotechnology corporation on software that streamlined the delivery of the COVID-19 vaccine.
  • Served as the chief technology officer (CTO) for a well-funded crypto startup valued at a $7 million market cap with over 50,000 transactions.
  • Contributed to one of the most prominent and rapidly growing fintech startups in the United States.
  • As a senior leadership team member, I managed a unit responsible for one of the market's most established AdTech creative automation products.
  • Authored a series of articles focused on best practices in authentication and authorization for the world's leading identity platform.
Technologies: Go, Java, JavaScript, TypeScript, Python, GraphQL, Android, iOS, React, React Native, PostgreSQL, Firebase, Kubernetes, Terraform, Amazon Web Services (AWS), Google Cloud, Experian, Amazon Cognito, Node.js, Plaid, Stripe, Fiserv, Ethereum, Web3.js, Advertising Technology (Adtech), PHP, Scala, Vue, Technical Writing

Chief Technology Officer

2019 - 2022
  • Oversaw engineering efforts and delivery, aligning the tech strategy with company OKRs. Ensured the implementation of modern practices, processes, and tools and guided leaders in international offices in adopting a similar operational approach.
  • Contributed to acquisitions, performed technical due diligence, and supported sales initiatives, leading to increased monthly revenue and higher hourly rates across the engineering team.
  • Managed technical recruitment, conducting numerous technical interviews since joining the organization.
Technologies: Team Management, Technical Leadership, Leadership, Tech Sales, Public Speaking

Technical Lead

2018 - 2019
  • Designed and developed an Identity Provider (IDP) for a multinational retail giant, substantially reducing running costs and eliminating all legacy issues. Improved user experience latency, crash reporting, and performance metrics.
  • Led the development of a mobile solution for Scandinavia's largest haircut provider, consolidating multiple services onto a single, scalable platform with a seamless API. This facilitated the company's effortless expansion across Europe.
  • Held responsibility for the technical output of teams developing some of Scandinavia's most popular applications.
Technologies: Python, Node.js, React, TypeScript, Swift, Kotlin, Java, Docker, Kubernetes, Google Cloud Platform (GCP), gRPC, Go, Technical Leadership, Technical Hiring, Leadership, Team Leadership, Team Management, Interviews, Interviewing, Mobile, Mobile APIs, Mobile Apps, Cloud, Google, Amazon Web Services (AWS), Heroku, Code Review, Open Source, Source Code Review, Presentations, Tech Sales, CTO

Engineering Lead

2017 - 2018
Lloyds Banking Group
  • Led a team of 10+ people responsible for the platinum journeys around payments and statements on the #1 UK banking app three years in a row.
  • Governed the adaption of a recent mobile acquisition onto our tech stack.
  • Engaged in technical debt burning, architecture, refactoring, and performance tuning of an app used by millions.
  • Performed code reviews across the whole mobile floor.
Technologies: Jenkins, Gerrit, Behavior-driven Development (BDD), JavaScript, iOS, Android, Kotlin, Java, Interviews, Technical Hiring, Interviewing, Code Review, Open Source, Source Code Review, Team Management, Distributed Team Management, Offshore Team Management, Cucumber, Leadership, Agile, Mobile Banking, Online Banking, Fintech, Architecture, Web Architecture

Senior Software Consultant

2016 - 2017
  • Served as the technical architect for a major healthcare client, investigating the feasibility of transitioning their web-based product to mobile platforms. Following my comprehensive report, the client successfully implemented the proposed solution.
  • Served as the Android lead for the UK's largest postal service, spearheading the development of an app that offered insights into employee operations, work environment, and behavioral patterns. This enhanced the accuracy of delivery predictions.
  • Conducted a thorough review of the largest UK-owned airport operator's Android app, successfully resolving numerous memory and performance issues and fixing various bugs.
Technologies: Xamarin, C#, JavaScript, iOS, Android, Kotlin, Code Review, Web, Interviews, Agile, Amazon Web Services (AWS), Python, Team Management

Senior Software Engineer

2013 - 2016
Full Tilt Poker / PokerStars
  • Spearheaded the entire development lifecycle of the Full Tilt Poker Android app, achieving over one million downloads across multiple distribution platforms in less than a year.
  • Optimized various components of the app, achieving speed improvements by factors of two to 20. Introduced form-factor independent UI elements, resulting in a notable uptick in tablet usage.
  • Achieved the IGA gaming app award for the Best Poker App of 2014.
Technologies: C, C++, JavaScript, iOS, Android, Leadership

Open Source Projects

I've contributed to various open-source projects across multiple technologies, including but not limited to gRPC, golden files, dependency injection, and cross-platform tools. My portfolio also includes tutorials, scripts, and various other resources, ranging from highly practical to experimental.

Lloyds Bank Mobile Banking

Lloyds Bank mobile app is used by over 8 million people daily. It was the #1 UK banking app for three years in a row, according to Forrester. I was leading a team of 10+ people creating platinum journeys involving payments and statements.

Technical Writing

I've authored a series of blog posts on constructing and securing a hypothetical API for a restaurant. These articles demonstrate established practices in authentication and authorization, utilizing technologies such as Java, Spring Boot, and Auth0.


Java, Go, Kotlin, Python, TypeScript, JavaScript, C#, HTML5, SQL, Swift, Objective-C, HTML, CSS, XML, YAML, Solidity, Ruby, Embedded C, C, C++, PHP, Bash, GraphQL, Scala


Spring Boot, Spring, OAuth 2, JSON Web Tokens (JWT), Flask, Flutter, Express.js, gRPC, Swagger, .NET, Ruby on Rails (RoR), Angular, Bootstrap, Kohana, PhoneGap, Django, Swing, React Native, Storm, Hadoop, Spark


Experian, Yodlee API Interface, REST APIs, Node.js, API Development, Slack API, Stripe, RxJava 2, OpenID, MooTools, SWT, jQuery, React, Eclipse SWT, Stripe API, Facebook API, GitHub API, Twitter API, Google Places API, Google Play API, Web3.js, Vue


Firebase Cloud Messaging (FCM), Git, Make, IntelliJ IDEA, GitHub, Auth0, Google Analytics, Gradle, Apache Maven, Fastlane, Terraform, Android Studio, Xcode, Gerrit, JetBrains, Shell, Jenkins, Sonar, Eclipse RCP, Cucumber, Jira, Visual Studio App Center, Amazon Cognito, Plaid


Automation, App Development, RESTful Development, REST, Clean Architecture, Scalable Application, Dependency Injection, Agile, Functional Programming, Microservices, Reactive Programming, Continuous Delivery (CD), Continuous Integration (CI), Event-driven Architecture, Test-driven Development (TDD), Unit Testing, Web Architecture, Web Application Architecture, Serverless Architecture, Continuous Deployment, Behavior-driven Development (BDD), Cross-platform, Testing, MapReduce, DevOps


AWS Lambda, Mobile, Android, Firebase, Google Cloud Platform (GCP), Twilio, iOS, Xamarin, Docker, Amazon Web Services (AWS), Ethereum, Azure, Kubernetes, Eclipse, Apache Kafka, Unix, Blockchain, Heroku, Web


JSON, PostgreSQL, Memcached, Databases, NoSQL, Redis, Realm, MySQL, Cloud Firestore, Google Cloud, Elasticsearch, PL/SQL, MongoDB

Industry Expertise

Banking & Finance


Software Development, Blockchain Development, Back-end, APIs, Authentication, Technology, Technical Leadership, SOAP, Minimum Viable Product (MVP), Mobile Architecture, Middleware, Software as a Service (SaaS), CTO, Fintech, Mobile Apps, Mobile APIs, Containerization, Containers, Software Architecture, Writing & Editing, Stripe Payments, Planning, Back-end Development, Firebase Cloud Functions, Data Scraping, Payment APIs, SOLID Principles, Open Source, Communication, Leadership, Architecture, Web Scraping, Mentorship & Coaching, Native Mobile Apps, Web Development, Full-stack, Team Management, Distributed Team Management, Technical Hiring, Interviews, Interviewing, Code Review, Source Code Review, Push Notifications, Scripting, SaaS, API Integration, Integration Testing, System Integration Testing (SIT), OAuth, CI/CD Pipelines, System Architecture, Progressive Web Applications (PWA), Cloud Services, Consul, Financial Services, WebSockets, FindBugs, Google Cloud Functions, Cloud, Serverless, Protocol Buffers, Algorithms, Data Structures, Analytics, User Experience (UX), Concurrency, Trading, Mathematics, Software, Cordova, Kotlin/Native, Mobile Banking, Machine Learning, Big Data, Offshore Team Management, Online Banking, Team Leadership, Google, Presentations, Tech Sales, Public Speaking, Technical Writing, Fiserv, Optimization, Advertising Technology (Adtech)

2007 - 2010

Completed Credits towards a Bachelor's Degree in Mathematics and Computer Science

University of Ljubljana - Ljubljana, Slovenia

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