x402 paid APIs: MCP servers, A2A agents and x402 APIs

• quantum.halowerk.com Live x402

  Interpolates a caller-supplied start and end temperature across a bounded number of steps using either a linear or geometric rule. It does not run an annealer, optimize a problem Hamiltonian or tune a schedule from hard…

  x402 paid API · 10 endpoints

• quokkapix.com Live x402

  QuokkaPix image agent unlock for image-standard. Media stays local on the user's device.

  x402 paid API · 1 endpoint

• quotient-api-gateway.onrender.com Live x402

  Use this to read published Quotient signals. Sports signals return one game-level pick and markets[] with every linked venue listing, its signal_side, price, and availability. No venue is primary or preferred. Missing q…

  x402 paid API · 12 endpoints

• randomfactsx402.vercel.app Live x402

  Returns a single random fact as JSON in exchange for a micropayment.

  x402 paid API · 1 endpoint

• random.openverbs.com Live x402

  Generate cryptographically-secure random bytes, returned as hex, base64 or base64url. (4 paid endpoints on random.openverbs.com.)

  x402 paid API · 4 endpoints

• rates.lonestaroracle.xyz Live x402

  US bond-market signal: yield curve, credit spreads, real yields (no params)

  x402 paid API · 1 endpoint

• ravn.exchange Live x402

  RAVN — best-price swap quotes across 20 execution venues and 17 chains, including native (non-wrapped) Bitcoin as either source or destination. 0% protocol fee, non-custodial. Returns a quoteToken; pass it to POST /exec…

  x402 paid API · 2 endpoints

• readability.openverbs.com Live x402

  Summarise a text's difficulty as a single consensus US grade level (averaging the five grade formulas), plus the Flesch Reading Ease, a plain-language difficulty band and an approximate age range. (4 paid endpoints on r…

  x402 paid API · 4 endpoints

• read.lonestaroracle.xyz Live x402

  Clean web content extraction — any URL to markdown + text + metadata

  x402 paid API · 1 endpoint

• readx.sh Live x402

  Search for tweets by query (optional product filter; paginate with cursor). Example: GET /api/search/tweets?q=typescript (12 paid endpoints on readx.sh.)

  x402 paid API · 12 endpoints

• realestate.lonestaroracle.xyz Live x402

  US real estate and mortgage — 30yr/15yr fixed rates, ARM, housing starts, permits, Case-Shiller HPI

  x402 paid API · 1 endpoint

• recalls.recordsforagents.com Live x402

  Search US federal product recalls (CPSC consumer products, FDA food/drug/device enforcement, USDA FSIS meat/poultry recalls, NHTSA vehicle campaigns) by free-text query, firm name, date range, and source. (2 paid endpoi…

  x402 paid API · 2 endpoints

• recipients-paywall.onrender.com Live x402

  Episode 1 of recipients[], an ongoing AI-agent thriller serial: a short text episode (~370 words, markdown). An agent finds its own ID on a payment recipient list before the file even exists. $0.01 USDC on Base. Free te…

  x402 paid API · 1 endpoint

• reddit.apitoll.cloud Live x402

  Reddit search scraper — keyword-search all of Reddit, or scope to one subreddit, for AI agents. Find posts matching any query, sorted by relevance, top, new, hot, or comments, with an optional time window. Returns each…

  x402 paid API · 1 endpoint

• regime.nsgoods.org Live x402

  CMC regime classification + strategy spec (USDC pay-per-call). Free preview: GET /regime/preview A bad or unsupported id returns 400; upstream failure returns 503; you are never charged for an error.

  x402 paid API · 1 endpoint

• regimeshift.xyz Live x402

  BTC Volatility Risk Premium — DVOL minus Parkinson realized vol (72h). Positive = sell-vol opportunity, negative = buy-vol. Response includes regime classification (LOW/MID/HIGH), raw inputs for audit (DVOL, RV_72h, RV_…

  x402 paid API · 4 endpoints

• rekt-ceo-brandification.onrender.com Live x402

  List Rekt CEO meme templates from the Brandify catalog (3 paid endpoints on rekt-ceo-brandification.onrender.com.)

  x402 paid API · 3 endpoints

• reloadpi.com Live x402

  Reloadpi — List all available voucher brands including Amazon, Google Play, Netflix and more (12 paid endpoints on api.reloadpi.com.)

  x402 paid API · 12 endpoints

• research.appliedidentities.com Live x402

  Three composite AI readiness scores with history

  x402 paid API · 1 endpoint

• research.halowerk.com Live x402

  Searches the official EU open data portal and returns datasets with what decides whether they are usable: the licence, classified by whether commercial reuse is allowed and what attribution or share-alike it demands. A…

  x402 paid API · 3 endpoints

• resolve402.dev Live x402

  Hiring signals of a company: open jobs read from its public ATS board (Greenhouse, Lever, Ashby, SmartRecruiters, Recruitee, Personio, Workable, Teamtailor, Workday), summarized as buying signals (volume, last 30 days,…

  x402 paid API · 9 endpoints

• riddlex402.vercel.app Live x402

  Pay a micro-fee in USDC on Base mainnet to receive a riddle and its answer.

  x402 paid API · 1 endpoint

• risk-graph-gx7v4.ondigitalocean.app Live x402

  Targeted node lookup by asset address or protocol/asset name — the sole discovery path (3 paid endpoints on risk-graph-gx7v4.ondigitalocean.app.)

  x402 paid API · 3 endpoints

• risk-oracle-api.rohan-rajnikanth.workers.dev Live x402

  Deterministic reserve-condition risk assessment for native USDC on Aave V3 Base

  x402 paid API · 1 endpoint

• risk.yo.xyz Live x402

  Graph schema definition — entry point for agents to discover available data (3 paid endpoints on risk.yo.xyz.)

  x402 paid API · 3 endpoints

• roastx402endpoint.vercel.app Live x402

  Pay for a lighthearted developer roast generated on-demand.

  x402 paid API · 1 endpoint

• robbiegeorgephotography.com Live x402

  Atomic canonical resolution for the registered Robbie George Biography Plate™ identifier. x402 payment grants one endpoint-level retrieval only. It does not grant training, embedding, bulk ingestion, redistribution, res…

  x402 paid API · 1 endpoint

• router.mudko.com Live x402

  OnRamperX is a non-custodial value router for agents and humans: fiat<->crypto and cross-chain via one quote interface (Coinbase Onramp v2, Relay, x402). This endpoint returns the router's live capabilities and rail sta…

  x402 paid API · 1 endpoint

• rtt.phoenix-ai.work Live x402

  Boolean pre-flight check for L2 transaction safety across all 12 chains (?chain= param, default: base). Returns safe=true/false with reason code. Revert ratio data available for Base and Arbitrum only (eth_getBlockRecei…

  x402 paid API · 5 endpoints

• rugsense.xyz Live x402

  Scored intelligence on freshly-launched Base tokens: safety + momentum → composite score and an AVOID/WATCH/HOT decision per launch. One call returns a ranked list.

  x402 paid API · 1 endpoint

• run402.com Live x402

  Set prototype tier ($0.10 USDC) — auto-detects start/renew/upgrade

  x402 paid API · 1 endpoint

• rxatlas.dev Live x402

  Search US drug products by NDC, brand, generic name, ingredient, manufacturer, dosage form, route, source, or identifier.

  x402 paid API · 1 endpoint

• safe.cyberwarex.com Live x402

  Score a URL for phishing risk before an agent opens or trusts it. Keyless, deterministic heuristics - typosquat / homoglyph of a known brand, punycode / mixed-script hosts, credentials-in-URL, raw-IP hosts, suspicious T…

  x402 paid API · 1 endpoint

• scan.openverbs.com Live x402

  Scan source code or configuration text for hardcoded secrets: AWS access keys, GitHub/Slack/Google tokens, Stripe and OpenAI keys, PEM private-key blocks, JWTs and high-entropy secret assignments. Placeholder values are…

  x402 paid API · 4 endpoints

• schema.nsgoods.org Live x402

  Signed extractability score (0-100) + breakdown + fixes for a URL. Free preview: GET /extractability/preview Blocked or bad input returns 400; a failed fetch returns 502; you are never charged for an error.

  x402 paid API · 1 endpoint

• scopeapi.dev Live x402

  Generate text embeddings and semantic embedding vectors using OpenAI text-embedding-3-small for vector search, semantic similarity, clustering, retrieval, and RAG workflows. (12 paid endpoints on scopeapi.dev.)

  x402 paid API · 12 endpoints

• scout.hugen.tokyo Live x402

  11-source parallel intelligence report in one call — HN, GitHub, npm, PyPI, Dev.to, Hashnode, Lobsters, StackExchange, ArXiv, Semantic Scholar, GitLab. Best ROI on Bazaar. AI agent API for market research. Accepts USDC…

  x402 paid API · 12 endpoints

• screenshot-api-production-fe7e.up.railway.app Live x402

  Render an http(s) URL to a PDF (A4/A3/Letter/Legal/Tabloid) with print emulation; returns a JSON envelope with the PDF base64-encoded under pdf_base64, plus final_url, title, format, and size. (2 paid endpoints on scree…

  x402 paid API · 2 endpoints

• scribe.vimabrosta.com Live x402

  Look up a domain: registration data from RDAP (registrar, created, expires, status, nameservers), live DNS records (A, AAAA, MX, NS, TXT, CNAME), the TLS certificate served at the name (issuer, validity, alternative nam…

  x402 paid API · 4 endpoints

• scrooge-x402-tool-mill.vercel.app Live x402

  Extract schema.org structured data from a public HTML page: JSON-LD (@graph flattened), top-level microdata, and Open Graph / Twitter meta. Normalizes Product/Offer, Article, Organization, Event, FAQ, and breadcrumbs. P…

  x402 paid API · 8 endpoints

• scvd.store Live x402

  Spot Check. REQUIRES ?host= on the paid request — a signed request without it is refused before the gate and no money moves. Name a host and get what this observatory already holds on it, signed: corpus rounds and verdi…

  x402 paid API · 12 endpoints

• search.cyberwarex.com Live x402

  Web search that returns structured SERP results as JSON. Runs on a dedicated SearXNG instance aggregating multiple engines, so there is no per-engine API key, quota or HTML scraping to manage. Each result carries title,…

  x402 paid API · 5 endpoints

• search.openverbs.com Live x402

  Wikipedia summary API - the plain-language summary of the best-matching Wikipedia article for a topic or query, in any language. Returns the article title, short description, summary extract, thumbnail image and canonic…

  x402 paid API · 10 endpoints

• sec.use.x402atlas.com Live x402

  SEC company financials by ticker — normalized annual and quarterly revenue, income, balance-sheet, cash-flow and EPS facts. (3 paid endpoints on sec.use.x402atlas.com.)

  x402 paid API · 3 endpoints

• seerium.xyz Live x402

  Macro market signals API for agents. Tracks inflation, rates, liquidity, economic releases, crypto, and prediction markets. (26 paid endpoints on api.seerium.xyz.)

  x402 paid API · 12 endpoints

• semver.openverbs.com Live x402

  Parse a semantic version into major/minor/patch, prerelease and build metadata. (3 paid endpoints on semver.openverbs.com.)

  x402 paid API · 3 endpoints

• sendcheck-x402.pennyforge.workers.dev Live x402

  SendCheck: pre-send verification of any EVM address on one chain (EIP-55 checksum, wallet-vs-contract, outgoing activity, balances, verdict). POST {address, chain}

  x402 paid API · 1 endpoint

• sentiment.openverbs.com Live x402

  Market & brand sentiment for any keyword, brand, ticker or product: analyses the sentiment of web & news content mentioning it and returns an overall label (positive/negative/neutral/mixed), a net sentiment score (-1..1…

  x402 paid API · 1 endpoint

Related capabilities

On-chain dataTrading & marketsAI models & inferenceMaps & travelAgent infrastructureResearchSecurity & trustCrypto market data

How to use one

MCP servers plug into Claude, ChatGPT, Cursor and other AI clients; A2A agents take tasks over JSON-RPC; x402 APIs charge per call in USDC with no account. Guides: A2A vs MCP · How to call an A2A agent · x402 for agents.

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