Building a circular future
Our engineering mission
Technology is part of everything we do at Sellpy. We care deeply about building great products, both for our customers as well as for our colleagues who are using our internal systems. Regardless if its integrating a new machine learning feature into our warehouse systems or deploying scalable search across millions of unique products our work has tremendous impact on the future success of Sellpy.
The key to our future success will be our ability to grow our knowledge by eagerly searching for new ways to solve problems and learning from each other. We believe in an environment where implementation discussions are encouraged and occur frequently and where every member contributes to the architecture of our product.

Tech stack
JavaScript. :) We use it through React and React native for all our clients and through Node on Heroku hosted servers, AWS lambda functions and Intel NUCs for our photo robots. We complement this core with interesting technologies such as GraphQL, React Hook Form, styled-components, Expo and much more. There are always new exciting technologies around the corner for us to explore.
To learn about our full tech stack you can visit our page on stackshare: https://stackshare.io/sellpy/sellpy#stack
Behind the scenes in Engineering
Meet Johan, Junior Full-stack Engineer
Starting out at Sellpy has been a wonderful experience. Being introduced to a modern well-built tech stack makes me want to expand my skills as a developer and through Sellpy I get the freedom and help required to do so. As always, a new project can be scary, but the team around me always answers all questions that arise as well as going far beyond to help and guide me through the issues.
Have you had a chance to be involved in exciting projects yet?
Having started only a couple of months ago I have already had the chance to work in interesting areas. The best project yet must be our Finland launch. Adding yet another region to our already expanding market was exciting. This project taught me a lot about how all our projects at Sellpy link together. It made me more self-sufficient and set me up for more responsibility in future projects.
Another ongoing project that I also find interesting and fun is our new Sellpy app. Taking Sellpy to the mobile market truly is the right thing to do and since we’re always adding new features there is clear progress every day.
Why Sellpy?
The best thing about working at Sellpy is that you get to work with a lot of different areas in our tech stack. This makes work engaging through the whole process and gives me a chance to really implement clean solutions and expand Sellpy as a product. Furthermore, it is nice to see the changes I make directly impact our users and make the Sellpy experience better. As a developer it is nice to see that you are valued and get the room to grow in all areas. For example, we have a concept we call Level up Day where we focus on improving our knowledge in a technical subject of each developer's choice. Sellpy also provides a generous working environment with flexible hours as well as a hybrid set up, which is important for me who is working remotely from Linköping.
I would recommend Sellpy as a workplace for any developer who is interested in full stack engineering, frontend development, JavaScript, React or simply someone who is ready to try something new. I would also recommend Sellpy to anyone who likes the idea of working in smaller teams with more focus on coding rather than meetings, more focus on individual responsibility but still a focus on teamwork. Sellpy is the workplace for the interested developer.
Meet Helena, Engineering Manager
I started part-time at Sellpy in 2019 as a Software Engineer. This was during my last year of studying at KTH and from the first day I felt that Sellpy was a perfect fit for me. Fast-forward one year and I was starting full time in the Internal team after having done my Master’s thesis at Sellpy as well. Now - after 2.5 years in total at Sellpy - I’ve started working as Engineering manager for the Internal team.

Can you tell us about interesting projects you have been a part of?
During my Master’s thesis I investigated the use of machine learning models for segmenting the images in our ads, a super interesting project that afterwards was put into production.
Another interesting feature was when I took part in improving our algorithm for picking orders in the warehouse, a fun but challenging project - especially since the problem is NP hard!
Lastly, a project that I’m currently working on is collecting and structuring data for our registered items so that we can re-use the data later on when we receive a similar item - an exciting feature that will help us process more items and create better ads.
Why Sellpy?
It’s very rewarding to work at a company that’s working towards transforming the very industry it’s part of. It brings unique challenges that no one really has solved before which at times can feel almost intimidating, but that feeling is quickly changed to excitement when all your colleagues are kind, fun and ambitious people that makes it a complete delight to solve these problems together.
I would recommend Sellpy to developers who want to make a big impact by finding simple solutions to challenging problems. Sellpy is growing fast, a developer’s opinion is valued highly and you will be a part of driving the company forward. I’d say that Sellpy is built on team players - we feel safe in knowing that we will always help each other out if needed, but you shouldn’t be afraid to trust your own skills as well!
3 teams of Engineering
Selling Services
Our sellers and their items is what makes Sellpy possible. Our unique and vast inventory is all thanks to them and we need to provide them with a great experience.

The Selling services team is responsible for the journey of our sellers. From their first bag order, through their items being described and photographed and all the way to the items being sold.
Buying Services
Access everything, consume nothing.
This is the vision of Sellpy. In order to reach that vision buying second hand items need to be as easy as buying new. The team is constantly working towards not just the best second hand experience, but the best e-commerce experience period. This is no small task and it involves great user interfaces, availability across devices and countries and accurate search and discovery.

We have come far on this journey but there is so much more to do!
Internal
Describing 250 000 items a week, Capturing more than 1 million images a week and sending 200 000 items a week. These are some of the great challenges of working with our internal systems. On top of that every item is unique!

Having doubled our processing ability in only a year we are in a very expansive phase and that results in very exciting challenges. We transfer items between warehouses, across borders, in order to provide the best experience for our customers. We automate photography with photo robots that ensure high quality and fast processing speeds. We make descriptions of items more accurate, provide tools for quality control and much more. Our internal systems are already international but the growth has only started!