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Latest · Oct 11 Post-quantum progress: signatures, backups and Tunnel test

Evidence-first x402 monitoring

Inspect x402 evidence before you integrate.

Check public x402 v2 endpoints: ownership, protocol behavior, availability, latency, freshness and signed provenance, each shown separately.

Monitor my endpoint
  • External observer
  • Named evidence
  • Signed provenance
  • No composite score
report hash Not loaded
SHA-256 / saved evidence

Public evidence lookup

Check what the monitor has actually observed.

Look up saved evidence for an exact public HTTPS URL, or submit an endpoint for monitoring. IFF only observes unpaid responses; it never signs or makes a payment.

Read an illustrated evidence example

Payment network

Mainnet views

Filter the endpoint's observed payment options by network. This changes only the view. Testnets and other networks appear under All networks. Network marks identify payment-network filters, not partnerships.

All networks selected. Enter an exact endpoint URL to inspect its saved evidence.

Public unpaid GET resources on HTTPS port 443. No credentials, query strings or fragments; keep parameters the provider requires.

Submit the URL for eligibility checks and unpaid monitoring. Use Check progress later to read status without resubmitting. Submission does not guarantee publication or verify ownership. Switching networks does not submit a URL.

Examples: inspect evidence or start monitoring

Inspect an existing observation

These two resources had public observations on September 6, 2026. Copy one above and choose Inspect evidence. Examples are not endorsements.

https://api.solmachina.com/v1/epoch
https://2s.io/api/geo/ip

Inspect a BSC observation

First observed September 6, 2026, 09:45 UTC, with a v2 challenge declaring eip155:56. Copy the URL, select BSC, choose Inspect evidence. Ownership is unverified and settlement was not tested. Gateway operator's source.

https://x402-gateway.bankofai.io/providers/dexscreener-dex-data-bsc/token-profiles/latest/v1

For another resource, choose Submit for monitoring; a card appears only after publication.

Live production proof

Follow evidence from observation to Base.

Loaded live from the same public APIs any verifier can query.

Production pipeline

Loading public signals…

Connecting…

  1. Observe

    Checking
    —

    Reading scheduled probe cadence.

  2. Append

    Checking
    —

    Reading the append-only log.

  3. Sign

    Checking
    —

    Reading the signed tree head.

  4. Anchor

    Checking
    —

    Reading ERC-8004 chain provenance.

Root hash fingerprint

Awaiting signed tree head

Read dimensions, not a rating

Evidence stays inspectable.

Ownership

Wallet-bound control of the origin.

Protocol

HTTP 402 behavior and x402 v2 requirements.

Operations

Sample counts, pass rates, latency, freshness.

Provenance

Report hash, monitor identity, signature, optional anchor.

How it works

From observation to reproducible evidence.

Observed-tier cards are public before an owner claims the endpoint and are labelled ownership unverified. Verified-tier publication needs proof of domain control plus at least three passing observations.

  1. 1

    Find evidence or claim ownership

    Read observed evidence without signing in. Owners claim an endpoint by publishing its wallet-bound challenge at the origin.

  2. 2

    Collect observations

    The worker validates unpaid x402 responses and records append-only operational evidence.

  3. 3

    Verify provenance

    Check the card, report hash, monitor signature and optional anchor.

Security boundaries

Know exactly what the evidence means.

What it establishes

  • The origin answered at a specific time.
  • The unpaid response matched named x402 v2 checks.
  • The report bytes match a signed hash.
  • An optional anchor records when a manifest hash existed.

What it does not establish

  • No paid canary transaction or delivery guarantee.
  • No claim that an endpoint is honest or safe to pay, even with a valid signature or anchor.
  • No composite trust score or hidden weighting.

Experimental showcase

Carry one IFF verification result with its signature.

Service Receipt v2 is an optional ML-DSA-65 (post-quantum) signed artifact for one /api/v3/verify response. It binds the exact result, a digest of the request and a five-minute action window. Inspect it locally with the open-source verifier.

What the showcase demonstrates

  • A signed IFF verification result can be carried elsewhere.
  • Request digest, signed subject, issuer policy and time window are checked separately.

Not an x402 payment receipt

  • It does not prove payment, service delivery, caller identity, remote execution, result correctness or safety.
Try the local verifier Read the optional feature guide

API quickstart

Use the same public evidence in your product.

Fetch the current evidence card by endpoint URL. Responses are cached for 30 seconds.

Walkthroughs: reading evidence, integrating, publishing an endpoint, reviewing a receipt.

Read the web docs Browse API reference Choose your guide
Public evidence lookup 
curl -G "https://ifandonlyif.io/api/v3/evidence/check" \
  --data-urlencode \
  "url=https://api.example.com/paid-resource"