Selly

Inspiration

Selling 2nd hand sucks. Making a listing, negotiating with potential buyers, and meeting up with a person isn't even worth making 10€ . We've personally left 100's of € on the table because the experience is so painful

What it does

Selly makes the 2nd hand selling experience smooth as butter. Just upload your pictures and let Selly take care of

Assessing quality
Finding a good market price
Putting up a listing with description
Negotiating the best price
And the payment link via bunq

Challenge: integrating with Marktplaats

When looking into our options for the second-hand auction platform to integrate with, we discovered that most existing platforms - including, for instance, Facebook marketplace or Etsy, do not provide a meaningful API for interacting with the ads. Marktplaats was no exception. However, we decided to go with it because of its popularity in the Netherlands.

To interact with Marktplaats, we used PlayWright. The system is very fragile, but we attempted to improve it by processing some fields with an LLM to avoid small changes in design. However, the overwhelming complexity of the system forced us to unroll to the old, finite-state-automaton interaction system. Besides, we periodically regenerate and preserve cookies between sessions to speed up the process. The trade-off, of course, is that the interaction with the marketplace is slow (around 10 seconds per message sent), which does not allow us to have real-time use of the system, but adds a "human-like" delay to interaction. Besides, the system is not robust to the different serving servers of Marktplaats: the US server serves a slightly different website, but different enough to lead to a significant slowdown of our system.

What is next for Selly?

We intend to integrate with more marketplaces and make the whole interaction more seamless. The first step towards this goal would be becoming an official data partner of Marktplaats, allowing us to access the internal API with minimal restrictions and bringing us closer to real-time interactions.