Benjamin Fajić

An in-production pay-as-you-go platform with 1+ million customers and 30,000+ users. I had a back-end-heavy full-stack role, working with Java and Spring Boot cloud-based microservices for an Angular front-end application. I used Docker and Kubernetes with a CI/CD pipeline on Jenkins and multiple Amazon services such as EC2, RDS, SES, SQS, and S3.

I handled many microservices, such as accounting, reporting, and CRM. I created integrations with payment and SMS providers and other third-party services. I also worked remotely in a distributed team using the Agile methodology, communicated with product owners, project managers, and other team members, and operated under on-call rotation off-hours to support critical issues.

A software solution for charging certain services using SMS. The application also has a CMS for managing companies and services, keywords, phone numbers, and users, and a dashboard with filterable and sortable data.

I developed and maintained the whole system. I implemented a database to fit requirements, wrote back-end logic to handle SMS processing, and communicated with mobile providers, external APIs, and software using this system for charging.

An online payment application that I developed to integrate with a bank gateway. This included a web API and a form-based front-end application that collects data from the end user, makes a request to the back end, processes that data, and returns a response. The front-end application either displays an error message or redirects the user to the bank's page for entering sensitive data. In the end, it displays the final result and emails an invoice to the user.

I worked on IEEE conference ticket purchases and handled the back end. I designed and implemented database solutions and web APIs for retrieving data from the front-end application. I also wrote logic for processing those requests, communicating with the transaction ID service, and returning a response to the front-end application.

A system that consists of a CMS with a back-end, database, and mobile application. Hosts or receptionists use the mobile app at the event to manage attendees by searching for guest names or scanning QR codes. After successful registration, the mobile app sends a request to the printer connected over the network to print appropriate accreditation.

I worked on the back end, implementing the database, specifying relationships and business logic, handling user authentication, and providing APIs for the mobile application. I also implemented different features on the CMS, including importing guest lists from Excel files or raw lists, sending invitations to guests by email, generating QR codes for guests, and sending event reminders. Additionally, I worked on features that presented all relevant data to event admins in the CMS and an external API that handled communication with the printer connected to wifi for requests to print.