I would look over the candidates who are currently, or over the past few years, working as a Golang Backend Developer at those companies. Then, we need to consider what we may learn from each profile.
If you are newer to the type of role, you want to be sure to take notes on any keywords you are not familiar with. Oftentimes, keywords may be a generalization that can be discussed several different ways on a profile. Once you know what tech/keywords you are looking for in your candidate, be sure to circle back and do further research on what you do not understand.
For example, if you are not familiar with “API” or “node,” go ahead and run a quick Google search to learn a little bit more about the tech. This will help you ensure that you are not missing great candidates who are speaking about their experience differently than your sample candidates.
For me, when I do not understand a type of tech, or I think I could be more creative with my search, I will pull up 3-4 different websites explaining the tech to make sure I am covering all my bases.
If you are able to speak to the research you did or keep data to reflect your work, you will be able to come to the table with the hiring manager with your expertise, and learn where you may be off base in the future.
Rather than jumping to an easy (but not always the best) solution, you can take some time to develop your toolset as a sourcer and create a strong relationship with your client by fostering a sense of trust and capability. Taking the time to research will not only save your hiring manager the time of writing up a job description, but will also establish you as a credible expert as a sourcer. You will also be developing strong habits and research skills to further your career. Next time you work on a role without a job description, see it as an opportunity to grow, rather than an inconvenience!