The whole price list, on one page, free tier first
Most verification pricing hides behind a sales call because the meter is complicated. This one fits in a table because the meter is call volume over time, and nothing else.
- Free, every day: 20 calls + 1 wrap-up. Pickup in another AI is always free. Enough to run and verify a real job daily.
- Day Pass, $0.99: unlimited calls for 24 hours. One payment, nothing renews. Get a Day Pass.
- Zambo Pass, $29 for 30 days: the working month, unlimited. $19 for $ZAMBO holders.
- Lifetime, $250 once: buy the product outright and stop thinking about the meter.
Zambo is the verifiable work layer for AI: 153 tools behind one MCP endpoint at https://zambo.dev/mcp, 37 on the default surface, and a verifiable AER-1 receipt for every call at every rung. A receipt proves the saved result was not changed since it was saved. It does not prove the answer was right, and any tool that prices itself on a stronger claim than that is selling you the claim, not the check.
Worked example: an agency proofing a month of client deliverables
Take a small agency that delivers AI assisted work to 12 clients and proofs every deliverable before it ships. Proofing one deliverable properly is not one call. It is the delivery job itself, plus the checks: open the job record, verify each step receipt, recompute the commitments, attach the proof pack to the client handover. Call it 25 receipted calls per deliverable, 12 deliverables a week, roughly 300 calls a week and about 1,200 calls in the month.
Now watch the ladder do its work. Day one, the free tier covers the first 20 calls plus the wrap-up. Call 21 lands mid morning, inside the second deliverable of the day: that is the wall, and it arrives while real client work is in flight, not during a demo. The agency buys a Day Pass for $0.99 and finishes the day unlimited. By day three the pattern is obvious, daily proofing is the job, so the month rung is the honest fit: $29 for 30 days covers the remaining 1,100 or so calls. Total cost of verifying a month of client work: about $30, against deliverables the agency bills in the thousands, and every proof is a receipt link the client can check without an account.
If the agency is still proofing client work in month three, the arithmetic flips to Lifetime: $250 once costs less than nine monthly rungs and ends the renewal question for good. That is the whole pricing story. No tiers named after metals, no per seat math, no quote.
What you are actually paying for
You are not paying for the receipt file. You are paying for call volume through an endpoint where every call is receipted by default, continuity carries jobs across AIs, and HANDOVER, the flagship product, wraps a job into a record a client can sign off on or dispute against. The free tier exists so you can verify that claim on your own work before any money moves: run a job, close it, open the receipts, change nothing, and check them at the verifier. Then run the same job past 20 calls and feel exactly where the paid rungs begin.
Start free: where the free tier ends, in plain numbers
Zambo gives you 20 calls + 1 wrap-up free every day, and picking up work in another AI is always free. Call 21 is where a job outgrows the free tier. The Day Pass is $0.99 for 24 hours unlimited. Ongoing, the Zambo Pass is $29 for 30 days ($19 for $ZAMBO holders) and Lifetime is $250 once. There is no per receipt fee and no per seat fee in this ladder: you pay for call volume over time, and every call at every rung leaves the same verifiable receipt.
Questions, answered
AI agent verification tool pricing: what does Zambo charge?
Four rungs, in order. Free: 20 calls + 1 wrap-up every day, pickup in another AI always free. Day Pass: $0.99 for 24 hours unlimited, at https://zambo.dev/day-pass/. Zambo Pass: $29 for 30 days, or $19 for $ZAMBO holders. Lifetime: $250 once. Every rung produces the same verifiable AER-1 receipts; the rungs differ only in how many calls you can run and for how long.
How much does AI agent verification cost for a heavy month?
Work it from volume. An agency proofing a month of client deliverables at about 300 receipted calls runs past the daily free tier on day one: call 21 lands inside the first morning. One Day Pass at $0.99 covers a single heavy proofing day. A month of daily proofing is the Zambo Pass at $29 for 30 days. A team that proofs client work every month stops renting at Lifetime, $250 once.
Is there a per receipt or per check fee?
No. Pricing is by call volume over time, not per receipt and not per verification. Checking a receipt at https://zambo.dev/verify/ is free for anyone, including the client you send the link to.
What does the free tier actually let me verify?
A real job, not a toy sample. Twenty calls plus one wrap-up is enough to run a multi step job, close it into one bound record, open each receipt, and recompute the hash commitments yourself. Verification quality is identical on the free tier; only volume is capped.