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Sample autocorrelation (ACF) and partial autocorrelation (PACF, Durbin-Levinson) of a series up to lag k, with 95% bounds.

Node4All Fortune — deterministic fortune reading derived from the x402 payment authorization nonce. Flagship demo of the Node4All x402 v2 payment flow. Operator: Node4All (https://node4all.com). Currency: USDC on Base.

Pay once to receive a short-lived WebSocket ticket for the live Bitcoin mempool stream.

UK VAT number format + check-digit test: Checks a UK VAT number's format and HMRC check digits (mod 97 / 9755). Catches fake or mistyped VAT numbers instantly without an HMRC call. Use /v1/business/check to confirm live registration.

npm / PyPI package metadata (keyless). Ecosystem + name → latest version, license, homepage.

Parse CSV into JSON rows keyed by trimmed snake_case headers. Offline. Amp port.

Base64 encode/decode UTF-8 text (standard or URL-safe). Offline. Amp port.

Calibrated 1X2 probabilities plus derived markets (totals, BTTS, correct score) for every upcoming fixture across the big-five European leagues. Backed by a public, Brier-scored track record.

Which US federal income tax bracket a taxable income falls in: marginal rate, bracket edges and dollars to the next bracket.

Sentence BLEU (1-4 gram, brevity penalty, optional smoothing) and ROUGE-1, ROUGE-2, ROUGE-L F1 for text against references.

Critical depth where Froude number is 1 (Q^2/g = A^3/T) for rectangular, trapezoidal, triangular or circular channels.

Floyd-Warshall all-pairs shortest distances for up to 100 nodes; negative weights ok; detects negative cycles.

Daily mean PM2.5, PM10, ozone, NO2 and US AQI over a date range, plus the count of days above an AQI threshold.

Battery bank layout (series and parallel counts) and runtime from load, voltage, Ah, depth of discharge and efficiency.

Check a US ABA routing number: 3-7-1 weighted checksum and the Federal Reserve district from the prefix.

Elo rating update after a game: win probability for each side, new ratings and the points exchanged.

Random fortune — fixed price; x402 exact or MPP one-shot

获取任意位置的天气

Local-only hex → utf8 / bytes32 / address / selector. No 4byte.directory. Offline. Amp port.

Canonical change monitor plan fetches current public evidence from the supplied target and evaluates the documented criterion. It returns the observation, threshold, verdict, exact evidence source, limitations and a mode-specific action. The check is passive: no login attempt, payload injection, exploit, purchase, form submission or load test is performed.

Inspect up to 200 IP addresses at 0.0005 USDC per address.

Author identity audit fetches current public evidence from the supplied target and evaluates the documented criterion. It returns the observation, threshold, verdict, exact evidence source, limitations and a mode-specific action. The check is passive: no login attempt, payload injection, exploit, purchase, form submission or load test is performed.

Four Pillars (BaZi) chart for a date and optional time: stems, branches, animals, five-element counts, day master.

Monitor recent official Israeli company-registry changes for an exact nine-digit company number. Returns filing and status-change events newest first, with dates, deterministic categories, source URLs, and checked_at. Use for counterparty monitoring, supplier due diligence, onboarding refreshes, corporate-event alerts, and registry change detection. Coverage is approximately one year.

List a country's holidays for a calendar year (optionally by state/region, language and type).

Perform the chant: 'All hail the Magic Conch!' The club responds: 'Hooray for the magic conches!' That is all this does, and it is enough.

Fetch one public HTML page → Markdown. robots.txt + SSRF guard + 1 MB / 5 s caps (amp port). Refusals 400 charged:false; fetch failures 502.

Parse markdown: outline, frontmatter, tables, fences, links, lists. Optional polite URL fetch.

Demo endpoint for x402 resource discovery

Is a vendor down right now? Current outage status for one SaaS vendor. $0.01 USDC on Base per call. Returns status, active-incident summary, last-checked time, source URL and freshness fields, read live from PulseWatch. Unknown vendors return 404, not charged. Don't use this for past incidents; use /v1/incidents.