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?

0.005000 USDC per request

https://api.n0brains.com/x402/signals

LOW 96/100

Observed 2026-08-15T14:32:50Z · 210 ms · HTTP 402 · v1 methodology

Endpoint

What we observed about the endpoint
URL	https://api.n0brains.com/x402/signals
Canonical	https://api.n0brains.com/x402/signals
Endpoint id	70ecd4a6a2995ebfc9d601cdddacaf11
HTTP status	402
Latency	210 ms
Redirects	0
TLS	handshake okThe negotiated TLS version is not exposed to a Worker.
Wire form	x402 v2 — PAYMENT-REQUIRED header
Bytes read	2
Strict decoder	accepteddecodePaymentRequired, imported from tx402 — the same code the SDK runs before it pays.

Payment

accepted by the decoder

These terms were accepted by the strict decoder tx402 uses before it pays.

The payment terms this endpoint asks for
Price	0.005000 USDC
Amount (atomic)	5000
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	0xc1793B8AA0D25193117EF025f145994e1c02011F
Pay to declared dynamic	nox402 v2 has no on-the-wire declaration of a dynamic payTo, so this is usually unobservable.
Authorization window	300s
Resource	https://api.n0brains.com/x402/signals
MIME type	application/json
Description	Real-time crypto trading signals for BTC, ETH, SOL and 400+ coins — classified by type (whale flows, funding, liquidations, listings, news, on-chain), scored, with direction, confidence and conviction. Emitted signals' forward-return record is public at n0brains.com/proof. Not financial advice.
Facilitator	not observed

Risk

LOW 96/100 · 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: pass 25 The challenge decodes 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: warn 4 The authorization window is outside 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

1 to look at

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

Result: pass wire_form_detected Served as v2-header.
Result: pass base64_strict The strict decoder accepted the header's base64 framing.
Result: pass json_wellformed
Result: pass x402_version_known Declared x402Version 2.
Result: pass accepts_present The challenge offers one way to pay.
Result: pass size_within_limit Read 2 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: warn max_timeout_sane Authorization window 300s exceeds the tx402 maximum of 60s.
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

first scan

First seen: just now · no history yet

Availability, latency and price stability need repeated observations over time. One probe is not a measurement of any of them, so none is shown.

This endpoint is now in the corpus, so the crawler will keep watching it. Price and recipient changes are recorded permanently; availability and latency are sampled.

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.n0brains.com/x402/signals" \
  --max-spend "0.005000 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: "0.005000 USDC",
    allowedDomains: ["api.n0brains.com"],
    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.n0brains.com/x402/signals");

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="0.005000 USDC",
        allowed_domains=["api.n0brains.com"],
        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.n0brains.com/x402/signals")

This report, as JSON or Markdown

curl -sS 'https://tools.tx402.io/api/v1/inspect?url=https%3A%2F%2Fapi.n0brains.com%2Fx402%2Fsignals'

# 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.n0brains.com%2Fx402%2Fsignals'

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: 1584f2c7c7d5bb44d4698d78bfe877b94d172a77837002c54decc1937b18ba57

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": true,
    "observed": true,
    "detail": null
  },
  {
    "id": "wire_form",
    "value": "v2-header",
    "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": "micro",
    "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": false,
    "observed": true,
    "detail": "Authorization window 300s exceeds the tx402 maximum of 60s."
  },
  {
    "id": "scheme_known",
    "value": true,
    "observed": true,
    "detail": null
  },
  {
    "id": "requirement_count",
    "value": 1,
    "observed": true,
    "detail": null
  },
  {
    "id": "challenge_size_bytes",
    "value": 2,
    "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