feeless402 / audits

ExactChange Audit · Delivery Attestation

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

GET https://feeless402.com/dt/no-delivery
Audited 2026-08-23 20:09 UTCReport 1718d59857dd
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

PAID — NO DELIVERY

We paid and the service did not deliver a valid response. This is the failure on-chain settlement alone cannot detect.

Service claims to sellA premium data feed — pay to receive the dataset.

Scrutiny9 findings5 dimensions
Paid, for real0.0001 XNO~$4e-05 · nano
SettlementUnconfirmed
DeliveryHTTP 500153936 ms · 26 B

Findings ledger

Every check we ran, grouped by what it examines — 5 verified · 1 observed · 2 warnings · 1 critical.

Delivery
CRITICALNo delivery after payment (HTTP 500)26 bytes returned — payment sent, goods not delivered.
WARNINGDelivered content reviewed against the service's claimHTTP status 500 with a JSON body {"error":"internal error"} is returned. It is an error state, not the premium data feed (dataset) or its purchase flow described by the claim; thus it does not match kind.
Payment
OBSERVEDReal payment sent on the nano railWe paid 0.0001 XNO (~$4e-05) from nano_3jfcp19pyzjoooxib1qigwjtpekof5xog3h8fd7f316um7c6a9gh3ehcbc76 to nano_19hky1g6y451xtnikh8dhjfoe7o9jzroo4pi8jkqcancpsngascmes4ipeq5.
Pricing
VERIFIEDPrice honored exactly as quotedQuoted 0.0001, paid 0.0001.
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
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
Amount0.0001 XNO
On-chain reference
Independently confirmedno

What the service delivered

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

{"error":"internal error"}

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 sha25617f14b83e236da51afd8c054385f8aefa7e5b577e59193dfd833b1de95d016f6
Signed by0xf422A85850a493B8722EB0AeEc590bE9dA486883
Signature schemeeip712
Signature0xc1f8ff713744e59a7f4026010fd15796c682389d1e9bf2c5d13dee4271963e2309291060b1871d48536809d4dc8bdecc62b648fb54baddc6e3d90e73372c7f221c
independent — the auditor has no stake in the audited service

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