These are observations, not accusations. A band of LOW, MEDIUM or HIGH describes how much of what we check we were able to confirm — it is not a judgement about the operator of an endpoint. Every signal, its weight and its rationale are published on the methodology page, and any operator can claim an endpoint, correct a fact or opt out.

What does this x402 endpoint charge?

0.031000 USDC as served — decoder refused

https://api.hyperextend.xyz/v1/trades/BTC

MEDIUM 76/100

Observed 2026-08-15T14:34:03Z · 1266 ms · HTTP 402 · v1 methodology

CHALLENGE_MALFORMEDAn x402 challenge was served, but the strict decoder refused it.

Endpoint

What we observed about the endpoint
URL	https://api.hyperextend.xyz/v1/trades/BTC
Canonical	https://api.hyperextend.xyz/v1/trades/BTC
Endpoint id	1b8c0d0c5cfbd4f976a078f608f1a294
HTTP status	402
Latency	1266 ms
Redirects	0
TLS	handshake okThe negotiated TLS version is not exposed to a Worker.
Wire form	both the v2 header and a v1 body
Bytes read	3128
Strict decoder	refusedInvalid PAYMENT-REQUIRED challenge: upstream-schema-invalid

Payment

as served

The decoder refused this challenge. The terms below were parsed out of what the endpoint served, so that whoever maintains it can see what we saw. They are not terms tx402 would pay.

The payment terms this endpoint asks for
Price	0.031000 USDC
Amount (atomic)	31000
Scheme	exact
Network	eip155:8453 in manifestRecognized means present in the tx402 signed release manifest. Nothing more is claimed.
Asset	USDC 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 in manifestRecognized means present in the tx402 signed release manifest. Nothing more is claimed.
Pay to	0x548fC289526ab2F0391D562a723cdA64Bbf1abc4
Pay to declared dynamic	nox402 v2 has no on-the-wire declaration of a dynamic payTo, so this is usually unobservable.
Authorization window	60s
Resource	https://api.hyperextend.xyz/v1/trades/BTC
MIME type	application/json
Description	Raw market trades over a time window — the live hot tier (~24h) plus S3 read-through for older history (archive from 2025-05-25), merged. Each row mirrors HL's WsTrade verbatim, including the buyer/seller addresses (`users`) and the trade `hash`. Priced per asset-hour ($0.015 base, $0.03 HIP-3/HIP-4) plus $0.05 per uncached archive hour pulled (warms the cache); ≤24 asset-hours/request.
Facilitator	not observed

Risk

MEDIUM 76/100 · v1 · static_only

A band describes how much of what we check we were able to confirm. It is not a judgement about the operator of an endpoint.

Result: fail 25 The challenge does not decode under the strict x402 decoder tx402 uses before paying. challenge_decodes
Result: pass 15 The challenge describes the endpoint that served it. resource_origin_match
Result: pass 12 The amount is a canonical atomic integer. amount_canonical
Result: pass 12 The recipient is a well-formed address for the declared network. pay_to_wellformed
Result: pass 8 The network is in the tx402 signed release manifest. network_recognized
Result: pass 8 The asset is in the tx402 signed release manifest for this network. asset_recognized
Result: skip — The challenge named no facilitator. facilitator_known
Result: pass 6 The payment scheme is one tx402 can route. scheme_known
Result: pass 5 The endpoint was reached over a valid TLS connection. tls_ok
Result: pass 4 The authorization window is within the maximum tx402 will sign for. timeout_sane
Result: pass 3 No redirect downgraded the connection. redirect_scheme_downgrade
Result: pass 3 The endpoint serves the x402 v2 header form. wire_form
Result: pass 2 The amount is within the range we see for x402 endpoints. amount_magnitude_band

Security

challenge refused

The strict decoder refused this challenge (TX402_PAYMENT_REQUIRED_INVALID), which is the finding that matters most here. The checks below describe what could still be determined from what the endpoint served.

A check that could not run reports skip, and a skip is never counted as a pass.

Result: pass wire_form_detected Served as both.
Result: skip base64_strict The decoder refused the challenge; the framing cannot be reported separately.
Result: pass json_wellformed
Result: pass x402_version_known Declared x402Version 2.
Result: pass accepts_present The challenge offers 2 ways to pay.
Result: pass size_within_limit Read 3128 bytes, within the probe's cap.
Result: pass network_caip2_wellformed network: eip155:8453
Result: pass network_recognized Recognized means present in the tx402 signed release manifest.
Result: pass asset_recognized Recognized means present in the tx402 signed release manifest.
Result: pass amount_atomic_canonical
Result: pass amount_positive
Result: pass pay_to_wellformed
Result: pass max_timeout_sane
Result: pass resource_origin_match
Result: pass scheme_known
Result: skip facilitator_known The challenge named no facilitator.
Result: pass mime_type_wellformed mimeType: application/json
Result: pass extra_wellformed `extra` carries 2 field(s), preserved verbatim.
Result: skip amount_within_observed_range needs our data No prior observations of this endpoint.
Result: skip recipient_matches_observed needs our data No prior observations of this endpoint.

Observed

What the corpus knows about this endpoint
First seen	2026-08-15T04:00:12Z
Last seen	2026-08-15T14:34:03Z
Scans recorded	2
Availability (30d)	not measured yet
Latency p50	not measured yet

Recorded changes to this endpoint's terms
2026-08-15T06:00:24Z	first_seen: challenge_hash — → 269dca4864273991c8d716d17070df72dceb1713ec1dfb9d259db0129c85515a

Test with tx402 →

Pre-filled with this endpoint's real terms. Your signer stays in your process — this service never sees a key, never asks for one, and cannot build a payment.

CLI — dry run, nothing is signed

npx tx402 call "https://api.hyperextend.xyz/v1/trades/BTC" \
  --max-spend "0.031000 USDC" \
  --network "eip155:8453" \
  --dry-run

# --dry-run stops after the policy decision. Nothing is signed and nothing is spent.

TypeScript

import { createTx402Client } from "tx402";
// Your signer stays in your process. tools.tx402.io never sees a key,
// never asks for one, and cannot build a payment.
import { signers } from "./signers.js";

const tx402 = createTx402Client({
  signers,
  policy: {
    maxPerRequest: "0.031000 USDC",
    allowedDomains: ["api.hyperextend.xyz"],
    allowedNetworks: ["eip155:8453"],
  },
});

// Policy and budget are committed before the signer is reachable, so a
// refusal here is a payment that was never authorized.
const response = await tx402.fetch("https://api.hyperextend.xyz/v1/trades/BTC");

Python

from tx402 import Tx402Client, Policy

# Your signer stays in your process. tools.tx402.io never sees a key,
# never asks for one, and cannot build a payment.
tx402 = Tx402Client(
    evm_signer=evm,
    policy=Policy(
        max_per_request="0.031000 USDC",
        allowed_domains=["api.hyperextend.xyz"],
        allowed_networks=["eip155:8453"],
    ),
)

# Policy and budget are committed before the signer is reachable, so a
# refusal here is a payment that was never authorized.
response = tx402.fetch("https://api.hyperextend.xyz/v1/trades/BTC")

This report, as JSON or Markdown

curl -sS 'https://tools.tx402.io/api/v1/inspect?url=https%3A%2F%2Fapi.hyperextend.xyz%2Fv1%2Ftrades%2FBTC'

# The same result as Markdown, for a terminal or an agent:
curl -sS -H 'Accept: text/markdown' 'https://tools.tx402.io/inspect?url=https%3A%2F%2Fapi.hyperextend.xyz%2Fv1%2Ftrades%2FBTC'

The challenge, as served

Public data: the endpoint serves this to anyone who asks. It is shown exactly as it arrived, truncated to the documented cap.

raw challenge

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

SHA-256 of the canonicalized challenge: 269dca4864273991c8d716d17070df72dceb1713ec1dfb9d259db0129c85515a

Raw signals

The exact input the scoring function was given. A signal we could not determine has observed: false and contributes nothing to the score — it is never counted as a failure.

signals

[
  {
    "id": "probe_ok",
    "value": true,
    "observed": true,
    "detail": null
  },
  {
    "id": "challenge_served",
    "value": true,
    "observed": true,
    "detail": null
  },
  {
    "id": "challenge_decodes",
    "value": false,
    "observed": true,
    "detail": "Invalid PAYMENT-REQUIRED challenge: upstream-schema-invalid"
  },
  {
    "id": "wire_form",
    "value": "both",
    "observed": true,
    "detail": null
  },
  {
    "id": "x402_version",
    "value": 2,
    "observed": true,
    "detail": null
  },
  {
    "id": "tls_ok",
    "value": true,
    "observed": true,
    "detail": null
  },
  {
    "id": "tls_protocol",
    "value": null,
    "observed": false,
    "detail": "The negotiated TLS version is not exposed to the probe."
  },
  {
    "id": "redirect_count",
    "value": 0,
    "observed": true,
    "detail": null
  },
  {
    "id": "redirect_scheme_downgrade",
    "value": false,
    "observed": true,
    "detail": "Cross-scheme redirects are refused."
  },
  {
    "id": "resource_origin_match",
    "value": true,
    "observed": true,
    "detail": null
  },
  {
    "id": "network_recognized",
    "value": true,
    "observed": true,
    "detail": "Recognized means present in the tx402 signed release manifest."
  },
  {
    "id": "asset_recognized",
    "value": true,
    "observed": true,
    "detail": "Recognized means present in the tx402 signed release manifest."
  },
  {
    "id": "facilitator_known",
    "value": null,
    "observed": false,
    "detail": "The challenge named no facilitator."
  },
  {
    "id": "amount_canonical",
    "value": true,
    "observed": true,
    "detail": null
  },
  {
    "id": "amount_magnitude_band",
    "value": "small",
    "observed": true,
    "detail": null
  },
  {
    "id": "pay_to_wellformed",
    "value": true,
    "observed": true,
    "detail": null
  },
  {
    "id": "pay_to_declared_dynamic",
    "value": false,
    "observed": true,
    "detail": null
  },
  {
    "id": "timeout_sane",
    "value": true,
    "observed": true,
    "detail": null
  },
  {
    "id": "scheme_known",
    "value": true,
    "observed": true,
    "detail": null
  },
  {
    "id": "requirement_count",
    "value": 2,
    "observed": true,
    "detail": null
  },
  {
    "id": "challenge_size_bytes",
    "value": 3128,
    "observed": true,
    "detail": null
  },
  {
    "id": "first_seen_age_days",
    "value": null,
    "observed": false,
    "detail": "No history yet."
  },
  {
    "id": "scan_count",
    "value": null,
    "observed": false,
    "detail": "No history yet."
  },
  {
    "id": "availability_30d",
    "value": null,
    "observed": false,
    "detail": "No history yet."
  },
  {
    "id": "latency_p50_ms",
    "value": null,
    "observed": false,
    "detail": "No history yet."
  },
  {
    "id": "price_changes_90d",
    "value": null,
    "observed": false,
    "detail": "No history yet."
  },
  {
    "id": "recipient_changes_90d",
    "value": null,
    "observed": false,
    "detail": "No history yet."
  },
  {
    "id": "recipient_unstable_undeclared",
    "value": null,
    "observed": false,
    "detail": "No history yet."
  },
  {
    "id": "terms_changed_within_24h",
    "value": null,
    "observed": false,
    "detail": "No history yet."
  }
]

JSON Markdown Methodology Error reference