At my arrival I got welcomed by Pedro, who had been the kindest host. The communication run very smoothly by whatsapp and he even gave me a map of Porto, suggesting places to visit.
The apartment was perfect, big enough for 1/2 people. It was not in the city centre but it was situated 4 minutes from the metro station and from there you could get into town in just 2 stops.
It had all the comfort I needed, it was also in a very nice and quiet neighbourhood, and in front of a big supermarket.
I would definitely recommend it, especially for solo travellers.