  Background - Startup companies are becoming important suppliers of innovative
and software intensive products. The failure rate among startups is high due to
lack of resources, immaturity, multiple influences and dynamic technologies.
However, software product engineering is the core activity in startups,
therefore inadequacies in applied engineering practices might be a significant
contributing factor for high failure rates. Aim - This study identifies and
categorizes software engineering knowledge areas utilized in startups to map
out the state-of-art, identifying gaps for further research. Method - We
perform a systematic literature mapping study, applying snowball sampling to
identify relevant primary studies. Results - We have identified 54 practices
from 14 studies. Although 11 of 15 main knowledge areas from SWEBOK are
covered, a large part of categories is not. Conclusions - Existing research
does not provide reliable support for software engineering in any phase of a
startup life cycle. Transfer of results to other startups is difficult due to
low rigor in current studies.
