What is the cheapest way to prove AI work to a client without building my own logging system?
The cheapest way that actually proves anything is free: run the job through a connection that saves a verifiable receipt at each step, then send the client the check link. Screenshots cost nothing and prove nothing. A self-written certificate costs nothing and is worth the same. Free beats both.
Rank the methods by what a skeptical client can check, not by sticker price. Screenshots: free, and they show a picture of a claim; they can be cropped, staged, or taken from a different run. Chat exports: free, and they show what the AI said, which is the thing in dispute. A certificate you write yourself: free, and it asks the client to trust the person being questioned. Each is cheap because the checking is impossible.
The execution-time record is the first method on the list that a client can verify without trusting you. On Zambo the job runs through one connection, each step is saved as a verifiable receipt (AER-1, IETF Internet-draft-zambo-aer1-21), and the client opens one handover link and checks the steps in a browser. The free tier covers a first job end to end; the demo takes a minute and mints a real receipt.
Cheap has a boundary, and it is honest to name it: the record proves the saved result was not changed since it was saved. It does not prove the work was good. But in a payment dispute, "the record was not changed" is exactly the argument that ends the argument, and it costs $0 to start and $0.99 for a full day when one job becomes a delivery day.
Table: proof methods ranked by what a client can check
Method | Cost | What the client can check. Screenshots | $0 | Nothing independently; a picture of a claim. Chat export | $0 | What the AI said, not what it did. Self-written certificate | $0 | Your say-so, formatted. Platform timestamps (Drive, email) | $0 | That a file existed at a time, not what produced it. Verifiable receipt plus handover link | $0 to start, $0.99 per proof day | Each step's saved result, recomputed in the client's browser, with gaps labelled.
Worked example
A public handover shows the shape: open https://zambo.dev/handover/45434a17-4afc-486a-9646-e689bcee4297 and read its acceptance view. Four steps, each checked, the client's decision recorded as accepted, and the release marked ok to release. Producing that cost the sender one free-tier job; checking it costs the client one click and no account.
Frequently asked questions
Are screenshots ever enough proof?
For friendly clients and small jobs, screenshots are often accepted because nobody is disputing anything. The moment money is contested, a screenshot is a claim, not a check. Keep them as illustration; never let them be the record.
Why not just export the chat?
An export shows what the AI said, including the part where it said the work was done. That is the statement under dispute. A step receipt shows what was saved at execution time, and the client can recompute it instead of believing it.
When does the free route stop being enough?
When proof becomes a habit rather than an event: daily client work, several deliveries a week, a team. That is what the $29 monthly pass is for. Occasional proof stays at $0.99 a day or free.
By Brennan Zambo, founder of Zambo.
Last verified: 2026-10-17.
Try a handover
A handover gives your client one proof link with verifiable receipts to review, then Accept or Flag.
try it: say 'use zambo to hand this over to <client>' in your ai