Sofia Office

Senior Data Scientist

Senior Data Scientist

Created:
March 4, 2026
March 4, 2026

Senior Data Scientist

Contact: gdj@weply.chat | 0883 683 960

Job location in Sofia, Bulgaria

We are looking for an experienced Data Scientist to join our development team in Sofia, Bulgaria. If you thrive in a fast-moving scale-up where your work ships quickly and has real impact – keep reading.

Who you are:

  • A hands-on builder who has worked in a startup or scale-up environment and is comfortable wearing multiple hats rather than owning a single, narrow domain
  • A curious mind who stays current with the latest in AI/ML and brings new ideas to the table
  • Someone who holds the bar high -  you move decisively but don't cut corners, because you know your work has a direct, measurable impact on real interactions at scale

What you need to succeed:

Requirements:

  • 3+ years of proven experience building models that run at production scale
  • Solid understanding of machine learning concepts and algorithms (supervised learning, unsupervised learning, and deep learning)
  • Hands-on expertise in building and deploying models at scale
  • A thorough understanding of the data science and machine learning development process
  • Strong proficiency in Python (NumPy, pandas, scikit-learn, TensorFlow/PyTorch etc.)
  • SQL (We use MySQL)
  • MongoDB query syntax
  • Fluent spoken and written use of English
  • Background in a startup or scale-up: you know how to operate without a large supporting team around you

Advantages:

  • Good working experience of at least one cloud infrastructure, ideally AWS
  • Familiar with the concepts of MLOps
  • Experience in building RAG systems
  • Experience in building chat bots
  • Experience with prompt engineering
  • Software engineering background

What we offer:

  • This is a full-time position that comes with an excellent salary and an opportunity to grow within the company based on demonstrated merit
  • The chance to work together and learn from one of the top AI/ML experts in Denmark
  • Supportive environment, where your impact is visible
  • Hybrid model of working
  • 25 days annual paid leave
  • Annual team building that gathers together the offices from Sofia and Copenhagen
  • Mini-team buildings and other local company events that run throughout the year
  • Modern office with fresh atmosphere and good transport links
  • Free beverages

Who we are:

SaaSscale-up in growth!
We develop and staff live chat features for companies that want to convert website visitors into leads. Today, we handle chats for 2400+ companies in the Nordic region and have ambitions to become the global market leader. The development of our product and engineering team is central to that ambition, and that’s where you come in to the picture.

We+ reply = Weply
We meet our customers visitors' needs for instant replies and personal customer experience via a dedicated and trained team of chat agents, ensuring a meaningful real-time engagement. Our chat solution is proven to increase conversions and customer loyalty.

By having real people assisted by artificial intelligence to answer chats, every inquiry gets a fast response and qualified leads are identified, delivered to our clients. This leaves them with more time to focus on their expertise. 

Team of Vikings
Our commercial team sits in our offices in Copenhagen, Denmark, while our product development team is based in Sofia, Bulgaria. We have a large network of chat agents spans in 130+ locations all over the world. True to the old Viking traditions, we are explorers, dreamers and occasional party-doers!

How to apply:

Send us an application with your CV by email to gdj@weply.chat and start the subject with “Data Scientist”.

Pro-Tip: Skip the cover letter and pitch us in 3 sentences why exactly you are the perfect match for our team!