feeless402 / audits

ExactChange Audit · Delivery Attestation

We paid this service, and here is exactly what happened.

GET https://feeless402.com/dt/price-discrepancy
Audited 2026-08-23 20:14 UTCReport afd8ec07c152
DEMONSTRATION CASE — this is a deliberately flawed reference endpoint operated by ExactChange to show what the auditor detects. It is not a real third-party service.
Verdict

DELIVERED — SETTLEMENT UNVERIFIED

The service delivered a valid response to our paid request; on-chain settlement could not be independently confirmed at audit time.

Service claims to sellA cheap lookup at 0.0001 XNO per call.

Scrutiny9 findings5 dimensions
Paid, for real0.0009 XNO~$0.00036 · nano
SettlementUnconfirmed
DeliveryHTTP 200124494 ms · 27 B

Findings ledger

Every check we ran, grouped by what it examines — 6 verified · 1 observed · 2 warnings · 0 critical.

Delivery
VERIFIEDResponse delivered (200, 27 bytes, 124494 ms)Content-Type application/json. Body fingerprint sha256:065ed241bd854299…
Payment
OBSERVEDReal payment sent on the nano railWe paid 0.0009 XNO (~$0.00036) from nano_3jfcp19pyzjoooxib1qigwjtpekof5xog3h8fd7f316um7c6a9gh3ehcbc76 to nano_19hky1g6y451xtnikh8dhjfoe7o9jzroo4pi8jkqcancpsngascmes4ipeq5.
Pricing
VERIFIEDPrice honored exactly as quotedQuoted 0.0009, paid 0.0009.
Protocol conformance
VERIFIEDPresents an x402 payment challengeHTTP 402 on unpaid request
VERIFIEDDeclares a supported x402 versionx402Version=2
VERIFIEDOffers at least one payment option1 payment option(s)
VERIFIEDOption 0 fieldsnano:mainnet: complete
WARNINGOption 0 price matches description — not metdescription advertises ~0.0001, machine amount charges ~0.0009 — CHARGED AMOUNT DIFFERS FROM THE ADVERTISED PRICE
Settlement
WARNINGSettlement not independently verifiedblock_info failed: Block not found

Payment receipt

The audit is only credible because we actually paid. This is the transaction, independently checkable on-chain.

Railnano
From (auditor payer)nano_3jfcp19pyzjoooxib1qigwjtpekof5xog3h8fd7f316um7c6a9gh3ehcbc76
To (service)nano_19hky1g6y451xtnikh8dhjfoe7o9jzroo4pi8jkqcancpsngascmes4ipeq5
Amount0.0009 XNO
On-chain reference
Independently confirmedno

What the service delivered

The first bytes of the response to our paid request, verbatim.

{"ok":true,"data":"result"}

Cryptographic appendix

Re-verify this report yourself: the body hash is signed by the same key that paid the service, so the attester and the payer are one.

Report schemaexactchange-audit/v0
Report body sha256a245be7bffa4d301c56d7381de0b77ea17fdc08d9f7a9e2a18d2932e0bceb70c
Signed by0xf422A85850a493B8722EB0AeEc590bE9dA486883
Signature schemeeip712
Signature0xe167bc855c850e45e9b784342c1fcb51c1e99664b621ab63a47064659438ad0170725a6d5ad8e083d9a9ca834862ee42e9be03ec84789ca4f765d605bb2a83b01c
independent — the auditor has no stake in the audited service

ExactChange Audit — the agent that reads the receipt. feeless402.com/audits