Open NoteCheck · Docs · How it works · Run locally

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Miden payments are private: the chain doesn't show who paid whom or how much. That's the point, but it leaves a gap when you need to prove a payment to the person you paid, or to your accountant.

NoteCheck fills it. Pay through your wallet, get a link, share it. Whoever opens the link sees the amount, the recipient and the sender, checked against the Miden network in their own browser, and nothing else about your account.

What's inside

Pay with a receipt	Send a private payment from the Miden wallet. When it's on chain you get a receipt link, optionally password-protected.
Ask to be paid	Create a payment request link with your address, the token and the amount. The payer opens it, pays in one step and gets a receipt to send back.
Receipt page	A plain-language check anyone can read: amount, paid to, paid from, whether the recipient has claimed it. Save it as a PDF with a QR code, or share it as an image.
Receive	The recipient's wallet gets the note privately; if it doesn't arrive, they can import it from the receipt.
Developer tools	Address and account ID decoder, felt and word conversion, Poseidon2 and RPO256 hashing, note tag and fee calculators, allowlist and invite-code check, each with a visual breakdown.
Docs	A built-in guide, FAQ and glossary.

Everything runs in the browser. There is no backend; the receipt lives in the link's #fragment, which browsers never send to a server.

Works on Miden mainnet and testnet. Independent project, not affiliated with Miden.

How a receipt works

sequenceDiagram
    autonumber
    participant P as Payer
    participant W as Miden wallet
    participant M as Miden network
    participant R as Whoever gets the link
    P->>W: Pay 250 to the recipient (private note)
    W->>M: Prove and submit
    M-->>W: Note committed
    W-->>P: Full note
    P->>P: Pack note + proof into a link
    P->>R: Share the link
    R->>M: Look up the note ID, check its spend status
    M-->>R: Included in block N, consumed or not

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When you pay from the Pay tab, your wallet sends a private P2ID note to the recipient. NoteCheck takes the full note from the wallet, waits until it is committed, and packs it with the node's inclusion proof into a link:

https://<site>/r#r1.<base64url(gzip(json))>

The JSON holds the serialized note file plus an optional memo and date. With a password the payload is encrypted (PBKDF2-SHA256, 600k iterations, AES-256-GCM) and the link starts with r1e.; send the password separately.

Opening the link:

1. decodes the note file and recomputes the note ID from its contents,
2. asks a Miden node for that note ID and compares the sender, tag and note type it reports,
3. asks whether the note's nullifier has been published, i.e. whether it was consumed.

Changing the amount or the recipient changes the note ID, so an edited receipt won't match anything on chain.

What a receipt proves These assets were sent as a note to this recipient account, by this sender account. The note was committed to the network, in a given block. Whether the note has been consumed, and when.

What it doesn't prove Who consumed it. For P2ID only the recipient can; a P2IDE note can also go back to its sender after a deadline, and the receipt says so. Anything else about either account. The memo and date: they come from the sender and are shown as such. That a payment wasn't presented twice. One payment is one note ID; record it.

Also worth knowing:

• Checking a receipt asks the Miden node about that note, so the node can link the note to its later spend.
• A receipt link contains the note's details. Only P2ID and P2IDE notes are accepted, because anyone who knows the details of a note without a target check could consume it.
• Token names come from the official Miden token list. A token that isn't in the list, apart from the network's own fee token, is marked unverified, since anyone can create a token with any name.

Receipts from the CLI

If you sent a note with the Miden CLI, export it in full format and use the Receipts tab:

miden export --note <note-id> --export-type full

or make the link in the terminal with npx notecheck receipt <note-id>.mno.

The notecheck package

The receipt and request logic is also an npm package with a CLI, in packages/notecheck:

npm i notecheck @miden-sdk/miden-sdk
npx notecheck verify "https://notecheck-miden.vercel.app/r#r1.…"

See its README and the format spec, SPEC.md. The app imports the package from source (the notecheck alias in vite.config.ts, vitest.config.ts and tsconfig.app.json), so both always run the same code.

Running it

Requires Node 22 or newer and Yarn 1.

yarn install
yarn dev        # http://localhost:5173
yarn build      # type check + production build
yarn test       # unit and component tests

The package has its own scripts (its tests also run with yarn test):

yarn pkg:build  # compile packages/notecheck to dist/
yarn pkg:test
yarn pkg:pack   # npm pack --dry-run: what would be published

Browser checks run against a running dev or preview server with your installed Chrome:

yarn smoke <base-url>
yarn smoke:extra <base-url>

LIVE=1 yarn test also runs a few tests against testnet, including a full payment with a local client standing in for the wallet. The images in this README are regenerated with node brand/readme-assets.mjs against a running preview.

Built with React, Vite and @miden-sdk/miden-sdk 0.17. The wallet connection uses @miden-sdk/miden-wallet-adapter.

License

MIT