> ## Documentation Index
> Fetch the complete documentation index at: https://docs.qedproof.site/llms.txt
> Use this file to discover all available pages before exploring further.

# Check a receipt yourself

> Verify a receipt's signature, Merkle inclusion, and on-chain anchor independently, without trusting QED Proof's API.

export const NotBuilt = ({what}) => <Note>{what ? `${what} is not built yet.` : "This is not built yet."} It's described here so you know what to expect, not as something you can use today.</Note>;

A receipt is only useful if you don't have to trust QED Proof to believe it. The reference checker in the open-source
[POAW repository](https://github.com/Nuraveda-Labs/POAW) verifies a receipt entirely offline (plus one optional RPC
call for the anchor), against nothing but the receipt itself and the issuer's published keys.

## What it checks

1. Parses the receipt and rejects an unsupported spec version.
2. Resolves `issuer.key_id` against the issuer's published key set, checks the key's validity window, and verifies
   the Ed25519 signature over the receipt body.
3. Recomputes the claim digest and confirms it matches.
4. If a `proof` is present, verifies the Merkle inclusion proof — and, if you pass an RPC URL, verifies the on-chain
   anchor too (see [anchoring](/concepts/anchoring)).
5. Reports the achieved [trust level](/concepts/trust-levels) and the verdict.

## Running it

From a checkout of the [POAW repository](https://github.com/Nuraveda-Labs/POAW):

```bash theme={null}
# fetch the receipt and the issuer's public keys
curl https://api.qedproof.site/v1/receipts/<receipt_id>      > receipt.json
curl https://api.qedproof.site/.well-known/poaw-keys.json    > keys.json

# check it, including the on-chain anchor
uv run spec/tools/check.py receipt.json keys.json --rpc https://sepolia.base.org
```

Leave off `--rpc` to check everything except the anchor (signature, schema, and Merkle inclusion), which reports the
anchor as `"not_checked_offline"` rather than skipping it silently.

The tool prints a JSON report, for example:

```json theme={null}
{
  "checks": {
    "spec_version": true,
    "schema": true,
    "integers_only": true,
    "key": true,
    "signature": true,
    "claim_digest": true,
    "inclusion": true,
    "anchor": true
  },
  "valid": true,
  "achieved_trust_level": 2,
  "verdict": "verified"
}
```

`valid` is only `true` if every applicable check passes. `achieved_trust_level` is what the checker could actually
confirm — 2 requires both a verified inclusion proof and a verified on-chain anchor; without `--rpc`, the ceiling is
1\.

## In the browser

<NotBuilt what="An in-browser receipt checker at qedproof.site/r/<receipt_id>" />

Until then, use the command-line checker above, or point any RFC 6962-compatible Merkle verifier and an Ed25519
signature check at the receipt's `body`, `signature`, and `proof` per the [receipt spec](https://github.com/Nuraveda-Labs/POAW).