The problem with sourcing engineers on paper
Every backend profile in your search claims the same five technologies. The list is aspirational for some of them, historical for others, and accurate for a few. There is no way to tell from the profile, which is why technical screening exists and why so much recruiter time is spent on candidates who were never going to pass it.
Public code changes that for the engineers who have any. You can see what someone actually builds, how substantial it is, whether they maintain things or drive by, and whether the tools on their profile appear anywhere in their work. That evidence is free to gather.
The catch is coverage. Most engineers, including many of the best, have nothing public. So this play runs the evidence leg and a broad market leg side by side and merges them, which gives you proof where proof exists and reach everywhere else.
What you get back
A merged shortlist where each row says which leg it came from. GitHub-sourced rows carry the evidence: what they build, how significant it is, and where the stack shows up in real code. Market-sourced rows carry the career history instead. Both are scored against the same spec, so the ranking is comparable across legs.
Variations worth knowing
Lead with the market leg for infrastructure roles. Ask for it explicitly. There is no point spending the session hunting for open-source evidence that structurally does not exist for that discipline.
Ask for the impact tier. Someone maintaining a widely used project is a different conversation from someone with a tidy set of personal repositories. Both can be excellent hires. They need different approaches, and knowing which you are looking at before you write the message matters.
Add the personal-site pass for the final few. Conference talks, blog posts and side projects are where you find the hook for an approach that does not read like every other recruiter message that week.
Where this goes wrong
Treating an empty code search as a rejection. Only public code on default branches is searchable. A missing fingerprint means the search could not see it, not that the person cannot do the work.
Letting the open-source leg dominate. If most of your merged list came from GitHub, the market half was under-run and you are looking at a biased sample of the talent pool. The play flags that rather than letting it pass silently.
Approaching people through their commits. Lead with LinkedIn. A recruiter email to an address someone published for bug reports lands badly, and it is the fastest way to acquire a reputation in a community that talks to itself.