I had a client six years ago. A startup from the Bay area was looking for a software engineer with video encoding background.
You don't find such filters on LinkedIn, so I used GitHub to look for these engineers. This is how I conducted the search:
Research what open-source libraries do video encoding specialists use. Think of FFmpeg, DivX, libvpx, etc. 1-2 hours
Find those repositories on GitHub. 3-4 hours
Research users who A) forked those repositories or B) contributed to the main repos. Probably 10-15 hours
Find contact details, personal websites, emails or LinkedIn profiles of the most promising prospective candidates. 8-10 hours maybe?
I recall having a short-list of candidates for the CTO. He interviewed 4 and one got an offer. Six years ago, I used this as a case study during some of my training sessions for recruiters on my YouTube channel:

YouTube channel: AI with Michal Juhas
Fast forward to 2026
Sourcing on GitHub is so much easier...
I built an open-source recruiting agent that can do all of the manual work for you.
Research libraries that your target candidates use.
Find those libraries on GitHub
Find contributors of those libraries
Find contact details of those contributors
Score and pre-select the most promising candidates
Create a document that you can download
How it works
STEP 1
If you open Calyflow.ai, and import the "GitHub Sourcer" agent, you put a simple prompt:
Find software engineers who specialize in video encoding.That's a very generic prompt just to demonstrate its functionality. You can write a better one, right? ;)

Calyflow > GitHub Shortlist Agent > Prompt
STEP 2
Wait for the agent to finish. It can take several minutes. #coffeeTIme

Calyflow > GitHub Shortlist Agent > Chat
STEP 3
Open the final short-list, review and engage with those people. You'll have their contact emails and websites. Isn't this amazing??

Calyflow > GitHub Shortlist Agent > Results
I show how to use tools like Calyflow during my online workshops. See what is inside: AI Recruiting Accelerator.
Cheers,
Michal
PS: A new group starts on Monday with a detailed plan, skills, ATS/CRM connectors, and Claude workflows. The Live Build is scheduled for Thursday.
