Senior Full Stack Software Engineer - Review team

Ljubljana, Slovenia | Product Development | Full-time | Fully remote


About Celtra

At Celtra, we are building two world-class products. The first product (Creative Enablement or CE) has already been a growing market leader for a couple of years now, helping companies such as CNN, TripAdvisor, Bloomberg, NBCU, and Business Insider monetize their advertising inventory. It covers the entire lifecycle of launching a campaign: ad product ideation and design, ad content production, trafficking tags, and tracking performance. With our second, younger product (Creative Automation or CA), we are chasing a much bigger opportunity by helping brands produce a massive amount of content better, faster, and more efficiently. Although its development is still in the early days, it already includes an impressive list of customers such as Spotify, adidas, Shopify, Unilever, P&G, LEGO, Lululemon, and many others. 


What is our team responsible for? 

Our clients are running global campaigns with 10k+ ads making it impossible to review and discuss ads one by one. Our team is making collaboration at scale possible with our purpose built preview tool facilitating overview of thousands of ads side-by-side, search capabilities, real-time commenting, annotations, and by tapping into existing communication channels such as Slack. 


Who are we searching for? 

We are looking for senior Fullstack software engineers with an appreciation for Frontend technologies to join the journey of building the Creative Automation team (CA). 

In the past we built 

  • Real-time collaborative commenting (like Google Docs)
  • A pin dropping to mark specific ad details.
  • High-performance infinite scroll of thousands of ads.
  • Google Doc like sharing capabilities.


What are the challenges ahead?  

We are facing many tech challenges such as:

  • Alternative ad overview layouts (grouping, sampling)
  • Integrating with existing client workflows - Slack app
  • Ad approvals
  • Comments with emojis and reactions 
  • Continues scalability improvements both on backend and frontend
  • Notifications pipeline revamp


What kind of tech stack do we use?

Our CA product is using NodeJs, PHP, MySQL, Redis and Python. For both products, on the front-end, we use Vue.js, NPM, Webpack and vanilla JavaScript when needed. Everything runs on the AWS cloud, and the Kubernetes cluster orchestrates it.


What are our expectations?

You care about clean code. You write high-quality, maintainable code and are aware of industry best practices and trends. You proactively identify possible technical issues before it turns into long-term problems,  and you encourage others to do the same. We always do code reviews to provide feedback and ensure code quality.

You have a product mindset. We are not a feature factory. We have cross-functional teams with engineers, product managers, and product designers who are crafting a solution for a problem since day one. There is a lot of fun in this phase, requiring a lot of ingenuity, hacking, and validating.

You have strong troubleshooting skills. You are not afraid to parse logs, look at machine metrics or go deep into the code to understand what went wrong. You do not jump to conclusions, but act based on facts and evidence. 

You’re a  team player. You work well in the team, are willing to share the knowledge, and want to help others as you know only a strong team can succeed.


What would be your responsibilities? 

  • Create performant interfaces that are a joy to use
  • Contribute to the technical direction of our modules, define them and execute on them
  • Help define and improve the architecture
  • Code, review other people's code, ensure code quality, be a good boy scout, etc..
  • Work with the Products, Customer support, and other internal teams to solve challenges
  • Teach and help junior/mid-level developers grow
  • Help plan and transfer old parts of the codebase to the state of the art



  • 3+ years of experience in programming and following modern software development processes. 
  • Have experience of building single-page applications using modern web technologies (Javascript / TypeScript / CSS / HTML) and frameworks (VueJS / React / Angular).
  • Have experience with server-side principles (scaling, concurrency, etc. and back-end technologies (PHP, Python, Golang, Ruby, etc.).
  • Have understanding and experience of relational databases (e.g., MySQL) or document databases (e.g., Mongo).
  • Have experience with writing a unit, integration, and end-to-end tests. 
  • Willingness to learn, sharing our passion for constant improvement 
  • Experience with complex business software and large codebases
  • Experience with developing and deploying performant frontend code
  • Show passion for learning, and help us learn too.
  • Be fluent in written and spoken English.


We appreciate:

  • Experience with TDD & CI 
  • A big plus is some interest in or experience with UX/UI
  • Understanding of various software paradigms and architecture styles (REST, OOP, functional programming, state management, etc.)
  • B.Sc. or higher in Computer Science or a related field  
  • Be open to collaborating in the tech community 


What do we offer? 

In Celtra it’s all about looking beyond the surface, beyond the numbers, and really trying to see the qualities that are at the core of each person, their talents; the discovered ones or better still, the undiscovered ones. We look for people who naturally want to take responsibility for their own success, and strive to do something that has a tangible impact. To our best talent, we give them the freedom to do the unusual. 


Here is what we offer:

  • A competitive benefits and compensation package 
  • We place great importance on the professional development of our employees 
  • Comprehensive health coverage and additional pension insurance 
  • We provide plenty of opportunities for employees to seek a more active and healthy lifestyle. We provide a dedicated budget for any kind of sport activities employees are passionate about, and we sponsor group sports activities such as basketball and yoga lessons. 
  • We provide employees with top-notch working equipment and an additional budget for your home office.