If I build a product on this idea, I know every job seeker under the sun would jump in but what about the employers? Does a market exist, can I expect early adopters?
Also you assume employees would love it. But what happens when you get blackballed in the system by a bad actor? How do you dispute what prior employers said about you?
Your best shot (imo) is to find a way to officially certify developers for a demanded tool. Otherwise I don't ever see this idea taking off.
I work through an agency, haven't done anything resembling a modern tech interview in 15 years.
Disclaimer: 10X Management represents me, but I post my own opinions, I don't speak for them.
The "every job seeker" who "jumps in" is in practice bottom of the barrel- that's why they are seeking. How are you going to make them more attractive than any of the certificate/upskill/bootcamp/yadda yadda things that already exist.
Moving a little higher up the abstraction tree, either you are taking responsibility for the work/person or you are not. If you are, then you are a contracting agency. If you are not, you are a body shop. These are both just cattle businesses. Employers are not finding their staff through those commodity channels.
That said, the hiring market is so broken for all sides a good sounding pitch that ignores the reasons for the breakage can probably get traction. But absent a strategy- like top of market consultancy as a service- or bottom market consolidate federal work programs/grants/yadda yadda into a single place- it doesn't seem like the legs will run that long.