Email attention, backed by a refundable bond.
zkBounce lets a sender post a refundable USDC bond on Base before a message lands. Good mail gets the bond back. Spam does not. Zero-knowledge proofs settle the result without exposing who anyone is.
Join the closed beta How it works
Status: Phase 0 feasibility. The contracts are unaudited and no product is live yet. The first closed beta is planned for 200 people.
How a bond works
Post a bond
Before sending, the sender posts a refundable USDC bond on Base. Payment comes before the message is delivered.
The recipient decides
The recipient can engage or simply ignore the message. Both are fine.
Settle
If the message was engaged with or ignored, the sender gets the full bond back. If it was spam or abuse, the bond is paid to the recipient and the protocol.
The problem
Sending spam is nearly free, so inboxes fill up. Filters guess. Pay-to-email schemes tax everyone, including honest senders.
A 2017 project called BitBounce tried a version of this idea and did not survive. We studied why, and we designed zkBounce around those lessons.
Who it is for
Senders
A legitimate sender only loses the float: the time the bond is locked. Nothing is spent if the message is welcome or merely ignored.
Recipients
Unwanted mail has a price. When a sender abuses your attention, the bond pays you, not an ad network.
The protocol earns only from punishing spam. It never earns from mail that is delivered fairly.
Our commitments
- No tokenNo token, no sale, no airdrop. Ever.
- No custodyzkBounce does not hold your funds.
- Private by designNo server-side matching. Your email address is never committed on-chain.
- Base + USDCOne chain, one stablecoin. No custom L1.
Want early access?
We are opening a closed beta for 200 people, starting with open-source maintainers and crypto infrastructure founders.