What counts as eligible research and development work for the SR&ED tax credit?

Eligible SR&ED work generally requires two things together: a genuine attempt at technological advancement, going beyond what's already standard or routine in the field, and real technological uncertainty, meaning it genuinely wasn't clear at the outset whether or how a particular technical problem could be solved using existing knowledge and standard practice. Work that simply applies well-known techniques, even skillfully, or debugs routine issues that any competent practitioner in the field could resolve, doesn't meet this bar.

The work also generally needs to follow a systematic investigation, some form of hypothesis, testing, and evaluation, even if informal, rather than simply trying something once and moving on without any structured process of experimentation. This is part of why documentation matters so much for a claim: CRA wants to see evidence of the technical problem, the uncertainty involved, and the systematic process used to try to resolve it, not just a finished product.

Because "eligible" work is defined by these substantive characteristics rather than by industry or company size, a genuinely small project with real technical uncertainty can qualify just as much as a large one, provided the systematic-investigation and advancement elements are actually present and documented.