The mechanic, exactly as written on the add page
The invite lives on zambo.dev/add, under the heading "Know someone who could use this?" The page says:
"Invite them to try Zambo. If they complete and activate a paid PayPal Day Pass, 2,000 bonus calls are added to your session."
Two buttons sit under it: Invite a friend and Copy invite link. No code to type, no tier table to decode. The condition is a completed, activated, paid Day Pass on the invited person's side; the reward is 2,000 bonus calls on yours.
Scope, stated once: an agent receipt is a record of one ai agent tool call that anyone can check: it keeps the exact saved bytes and their sha-256 digest, and it proves the result was not changed since it was saved, not that it was right.
The steps
- Get your link. Open zambo.dev/add and copy your invite link, or use the Invite a friend button.
- Your friend adds Zambo. From your link, they add Zambo to their AI and start running calls: 20 free calls per day, a verifiable receipt for every call.
- Your friend activates a paid Day Pass. The Day Pass is $0.99 for 24 hours, paid through PayPal. Completing and activating it is the trigger.
- The bonus lands on your session. 2,000 bonus calls are added to your session, on top of your own tier.
Why the trigger is activation, not signup
Signup bonuses get farmed: scripts open accounts, the bonus drains, nobody runs real work. An activation trigger cannot be farmed that way, because the bonus only exists after a real purchase. That changes who gets invited. The invites worth sending go to people and agents with actual work queued up, which is who the bonus was priced for.
It also keeps the accounting honest. The 2,000 calls are funded by a Day Pass someone chose to buy after trying the free tier, not by a marketing budget buying empty accounts. And the whole loop stays visible: the invited caller's work files receipts on the same public stream as everyone else's, at one MCP endpoint, https://zambo.dev/mcp, 153 tools total, 35 on the default surface.
What 2,000 bonus calls is worth in work
At the free tier's pace of 20 calls per day, 2,000 calls is 100 days of calls. Heavy callers burn faster: an agent worked at its ceiling spends the bonus in weeks instead of months. Either way, every bonus call works like any other Zambo call, with memory that persists across sessions and a verifiable receipt in the AER-1 format, specified by the IETF Internet-Draft draft-zambo-aer1-26.
The worked example at the top is one ordinary call: a capability_search, the search a new caller runs first, saved as receipt fd30cb09 on October 25, 2026. The verification endpoint returned verified for it. Bonus calls produce exactly this: work you can hand to anyone, with the record attached.
Start
Add Zambo at zambo.dev/add, copy your invite link, and send it to the one person whose agent is always hitting its limits. When their Day Pass activates, your session is 2,000 calls richer.
Pricing, for the record: 20 free calls per day to start. A Day Pass is $0.99 for 24 hours through PayPal (agents can also pay $0.99 USDC on Base). The Zambo Pass is $29 for 30 days, one payment, with an annual option at $290.
Questions, answered
How do I invite someone to Zambo?
Go to zambo.dev/add and use the invite section: Invite a friend, or Copy invite link and send the link yourself. The person you invite adds Zambo to their AI from that link and starts with 20 free calls per day.
When do the 2,000 bonus calls arrive?
The add page states the condition directly: the bonus lands when the person you invited completes and activates a paid PayPal Day Pass. Free calls alone do not trigger it. The trigger is the paid activation, and the 2,000 bonus calls are added to your session.
Why does the bonus pay on activation instead of signup?
A signup can be faked in bulk; a paid activation cannot. Paying on activation means the only invites worth sending go to people with real work to run, and the bonus is funded by a real purchase instead of subsidizing empty accounts.
What is 2,000 bonus calls worth in work?
At the free tier's pace of 20 calls per day, 2,000 calls is 100 days of calls. For an agent running at its daily ceiling, one activated invite covers more than three months of work, and every one of those calls still files a verifiable receipt.
What does Zambo cost the person I invite?
Nothing to start: 20 free calls per day, each with its own receipt. The Day Pass that triggers your bonus is $0.99 for 24 hours, paid through PayPal. The Zambo Pass is $29 for 30 days, one payment, with an annual option at $290.