Work · Karbonity
Trade a renewable-energy certificate. Keep the buyer out of the public record.
Project · Live prototype on Midnight preview · Built with the Midnight Solutions Team under a Midnight Foundation grant, third milestone delivered April 2026, remaining work nearly complete · 2026 · Midnight Foundation grant
- Which buyer bought which certificate, on the public ledger
- The buyer's secret that unlocks a purchase, away from the chain and the bot
- A buyer's full holdings and retirements
- That a certificate was created under a named issuer, with its source, region and scale
- That it is listed, sold or redeemed
- That a holder can prove a certificate is theirs, when they choose to
The problem, as they feel it
An issuer certifies that a unit of renewable energy was generated. Buyers want those certificates, and want to prove they own or retired them. What nobody wants is a public ledger that shows who bought what, because a company's purchases say a great deal about its operations, and a certificate that can be traced back to its buyer is a liability as much as an asset.
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What it is
Karbonity is a marketplace for renewable-energy certificates from several issuers, on Midnight. A certificate is created under a named issuer with its source, region and scale. A holder lists it for sale or retires it to claim its benefit permanently. A buyer browses, buys and redeems, and can prove a certificate is theirs whenever they need to, without their identity leaving with the proof.
Two paths for two kinds of write
The part worth drawing is how a write reaches the chain, because there are two kinds and they must not be treated the same.
- The Lace wallet
- The purchase intent
- Proof of ownership, when asked for
- The buyer's secret noncenever reaches the chain or the bot
- Listing
- Price
- Unlisting
- The burn that completes a redemption
Public-state writes, the ones that change what everyone can see, go through a bot: listing, pricing, unlisting, the burn that completes a redemption. Nothing in that path is secret.
Buying, withdrawing and proving ownership each carry a secret only the buyer may hold. Those are signed in the buyer's own wallet, in the browser, and the secret nonce behind a purchase never reaches the chain or the bot. The bot cannot buy on your behalf because it never has what it would need to.
Where it stands
Karbonity was the platform for the ZkyProof pitch-day demo in Build Club Cohort 1: the same marketplace, a very different asset. The repository carries a written spec, not yet built, for agents acting for a buyer through a pluggable signer. The RWA framework, the base new projects start from, was extracted from work like this.
The facts
- StatusLive prototype on Midnight preview
- Backed byBuilt with the Midnight Solutions Team under a Midnight Foundation grant, third milestone delivered April 2026, remaining work nearly complete
- When2026
- FundingMidnight Foundation grant
- Built onCompact contracts on Midnight; a React front end with a Convex real-time backend; a Fastify and Inngest workflow server for the public-state writes; the Lace wallet for the writes that carry a secret.
- Live atkarbonity.eddalabs.io
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