A live demo proves something works. How do you prove what you contributed?

I’m validating Workly, a freelance network based on actual project work, and I’m trying to avoid a weak definition of “proof.”

Different artifacts seem to answer different questions:

• A live demo shows that something works, but not who actually built it.
• A repository exposes implementation, but a lot of client work is private.
• A case study explains decisions, but the claims are self-reported.
• A client reference adds credibility, but creates another task for the client.

That leaves a problem I’m trying to understand:
How does a developer prove meaningful contribution to a project without publishing confidential code or writing a huge case study?

If you’ve done paid frontend, full-stack, or AI development, think about the last time a client asked for evidence of your ability:

1. What did you show them?
2. Did they actually inspect it?
3. What did they still need to verify?
4. Was there important work you couldn’t show because it was private?

I’m also interested in cases where a referral or conversation mattered much more than any portfolio, GitHub profile, or demo.

The decision I’m trying to make is whether a structured project record would actually help freelancers, or whether it would just become another portfolio they have to maintain.

If you want context on what I’m validating:
https://workly-landing.pages.dev/?utm_source=devto&utm_medium=post&utm_campaign=freelancer_validation&utm_content=proof_of_work_v1