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QR Code Generator qr: Encode one text as a QR Code (ISO/IEC 18004, versions 1-40, ECC L/M/Q/H) and return it as SVG, PNG or a JSON matrix.

DOI metadata via Crossref (primary) + OpenAlex fallback. Title/authors/year/venue/URL.

Use Check for a changed/unchanged signal and optional compact text diff. Exactly one URL or existing watch ID; URL plus rules can create a watch, whereas watch_id reuses saved rules and forbids overrides. Use Smart Diff for structured changes. On-demand only; x402 $0.005 USDC on Base, including cache hits.

Committed IFTA tax rates for a quarter (?quarter=2026-Q2&fuel_type=diesel&jurisdiction=WA), grouped by jurisdiction × fuel type with effective periods clipped to the quarter — mid-quarter revisions read as separate periods. Human-reviewed against iftach.org every quarter.

Static Python lint (ruff) of one snippet/file up to 200KB

Extract links from URL or markdown; status + redirect + canonical; polite rate; honor robots.

Nested JSON → flat path-value map. Offline deterministic. Distinct from json-toolkit. Amp port.

Axial stress, strain and elongation from load, area, E and length; thermal strain/stress; factor of safety vs yield.

Precursor Detection - Catches risk signals before events materialize

Offline JSON Schema gate (type/required/properties/items + formats). Validate only — not schema-json-repair. Amp port.

Access to protected content

Bible book facts: chapters, testament, order and abbreviations for one of the 66 books, or the full table (1189 chapters).

List Rekt CEO meme templates from the Brandify catalog

Access to protected content

Dates for every N business days, or the last or Nth business day of each month, skipping weekends and your holiday list.

Access to protected content

Optimal Tower of Hanoi move list for up to 10 disks between pegs A, B and C, and the minimum move count 2^n - 1.

Flow rate in gpm and litres per minute from a bucket test: container volume and seconds to fill, with a daily-use estimate.

Deterministic keyword extraction (term frequency, stopword filter). Pairs with url-to-markdown / condense. Amp port.

Strip scripts/styles from HTML → readable text or markdown. Offline; no network. Amp port.

Detect Trojan Source bidi controls (CVE-2021-42574): overrides, isolates, unbalanced openers, stray closers, with positions.

Top Nostr notes and authors by sat-zap velocity over a rolling window. Surfaces real-money sentiment — who the BTC/Nostr economy is literally paying to amplify. Fundamentally different signal from reposts/likes: zaps cost sats. Query ?window=15m|1h|6h|24h &scope=notes|authors &limit=N.

Single-fact: timestamp + age of the most recent Zcash block, plus hash, difficulty, and size.

Official drinking-water file for an address or lat/lng (relocation / lodging due diligence). clear/caution/avoid from EPA, Hub'Eau, or JMP. Never invents grades.

Validates an 18-digit Mexican CLABE (sent as a JSON body, not a query param): check digit, bank identification (Banxico/SPEI catalog), plaza, and account number.

NYISO real-time zonal LMP via EnergyFeed

Perform fresh TCP service identification against a public IP address or hostname and port. Returns protocol, detected service, software product, version and CPE information where observable.

Deterministic line/word/char diff with one-line delta summary. Offline. Amp port.

List catalogued stars in an IAU constellation (name or 3-letter code), brightest first, with an optional named-only filter.

Invisible bot protection. Score form submissions 0-100 based on behavioral signals. No CAPTCHAs.