{"uid":"cap_WcBRAfR7zYyJo5R4BfYg6","slug":"rate-hub-api-mcp-endpoint-41fdc0d7","name":"rate-hub API MCP Endpoint","description":"**Access.** A deployment runs in one of two modes and the free `GET /v1/x402` tells which: it answers `200` with the offer on an x402 deployment and `404` on a classic one.\n\n- **x402 deployment** (the public one). There is no API key. A payment of USDC on Base buys a credit token for a pack of requests. Call a paid route without credentials: the answer is `402` with the offer in the `PAYMENT-REQUIRED` header (base64 JSON) and in the body. Pay by repeating the request with a `PAYMENT-SIGNATURE` header (base64 JSON x402 v2 `PaymentPayload`, scheme `exact`). The paying response is the normal answer plus `X-Credit-Token` (your token), `X-Credit-Remaining` and `PAYMENT-RESPONSE`. Keep the token and send `Authorization: Bearer <token>` on every later request. A token that is unknown, spent or expired, and any payment that cannot be accepted, answer `402` again: every payment problem is a `402` with a snake_case reason in `error`, never a `400`. On `/mcp` the same problems come back as `200` tool results, see `/mcp`. A `503` with `Retry-After` can mean the same payment is being processed right now: retry shortly. If the payment facilitator does not answer, the answer is `502` and nothing is charged.\n- **Classic deployment.** The client sends its key in the `X-API-Key` header. A missing or unknown key answers `401`.\n\nPaid routes: every `/v1` path except `GET /v1/x402`, and MCP `tools/call`. Free: `GET /v1/x402`, `/healthz`, `/readyz`, `/version`, `/openapi.yaml`, `/openapi.json` and `/.well-known/x402` (x402 deployments only), `/docs` (with `/docs/behavior` and `/docs/behavior.md`), `/llms.txt`, and the MCP methods `initialize`, `ping`, `tools/list` and `notifications/*`. On an x402 deployment every served request costs one credit, whatever its status, except `5xx`, which is refunded. Requests that match no route (`404`, `405`) are free.\n\nClient rules, in order. Read these before the paths.\n\n- Ignore unknown JSON fields. The server adds fields without a new major version.\n- Map an unknown enum value to an `unknown` case. A Swift `Codable` enum with no fallback crashes the decode and drops the whole response.\n- Honor `Retry-After` on `429` and `503`. The header is always an integer number of seconds, never an HTTP-date. `pending` rates carry `retry_after` in seconds for that asset only.\n- Fiat live quotes: `source_code` `s10` is a live rate table with no observation time of its own, so `as_of` is the fetch instant (about every 30 minutes by default); `day_change_pct` and `high_volatility` stay a move against the last rate of the previous UTC day, not against the previous poll. A currency that table does not cover keeps its last quote (`source_code` `s3`, `as_of` midnight UTC of that document's date) and turns `stale` after the fiat stale limit. Fiat daily quotes (`/v1/rates/daily`, `source_code` `s3`): `as_of` is midnight UTC of the upstream document date (the rate for that UTC calendar day), not the fetch instant. When present, optional `day` (`YYYY-MM-DD`) repeats that calendar day explicitly. Optional `fetched_at` is when rate-hub last received the live quote from upstream.\n- Freshness: live responses (`/v1/rates`, `/v1/top`, `/v1/assets`, `/v1/meta`, errors) carry `Cache-Control: no-cache`, so a client or CDN must ask again before reusing one. A refresh always returns the newest snapshot rate-api holds, so the collector's polling cadence is the floor on freshness. Judge a price by `as_of` (when the price was observed) and `fetched_at` (when rate-hub last refreshed it), not by when you asked.\n- `server_time`, quote `as_of`, and quote `fetched_at` use RFC3339 with millisecond precision (fractional seconds trimmed; no sub-millisecond noise).\n- Integration tests can observe `pending` by requesting a catalog uid that has no row in the loaded in-memory quote snapshot (for example a cold asset before the first lazy fetch).\n- Back off exponentially with jitter. Do not retry in a tight loop.\n- Prices and percent changes are decimal strings, never JSON numbers. Parse them with a decimal type. Do not use binary floating point.\n\nEdge cases this schema does not show (dynamic coins and their changing uids, placeholder icons, series limits, data lifetimes) are in the [behaviour notes](/docs/behavior) ([raw Markdown](/docs/behavior.md)).\n\nConventions: lowercase `snake_case`, full field names, statuses as strings, versioned under `/v1`. Changes inside v1 are additive only.\n\nPrices are rounded to 10 significant digits. This service is an indicative cache, not an oracle. Live `/v1/rates` quotes are not a full history product; additive `/v1/rates/daily` returns one immutable USD (or requested `vs`) rate per catalog uid per UTC calendar day for backfill and prewarm (see those paths for day definitions and archive limits).","url":"https://x402-v1.sky-1.org/mcp?utm_source=zero.xyz","method":"POST","headers":{},"bodySchema":{"type":"object","required":["method","jsonrpc"],"properties":{"id":{"type":"string","description":"Request id, a string or an integer. Absent for a notification."},"method":{"type":"string"},"params":{"type":"object"},"jsonrpc":{"enum":["2.0"],"type":"string"}}},"responseSchema":{"type":"object","description":"JSON-RPC 2.0 response."},"example":null,"exampleRequest":null,"tags":["x402"],"displayCostAmount":"0.05","displayCostAsset":"USDC","priceDynamic":false,"priceHint":null,"priceStatus":"priced","priceSource":"probe","requiresHandshake":false,"reviewCount":0,"rating":{"score":"0.00","successRate":"0.00","reviews":0,"stars":null,"state":"unrated"},"availabilityStatus":"unknown","priceObserved":null,"sessionDeposit":null,"pricing":{"kind":"static","summary":"$0.05/call","primary":{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.05","per":"call","confidence":"exact"},"accepted":[{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.05","per":"call","confidence":"exact"}]},"paymentMethods":[{"uid":"pm_jva_fhoPM7Q0f9kExFq5z","protocol":"x402","methodType":"crypto","chain":"base","mode":"charge","costAmount":"0.05","costPer":"request","priority":0,"asset":"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913","unit":"request","depositMicros":null,"planRef":null}],"brandName":null,"brandSlug":null,"brandBaseUrl":null,"brandDocsUrl":null,"whatItDoes":"Provides access to rate-hub API capabilities via MCP (Model Context Protocol) JSON-RPC 2.0 interface, gated by x402 USDC micropayment on Base","exampleAgentPrompt":"Can you query the rate-hub API for current rate data using the MCP interface? I'll pay with USDC on Base — use my credit token if I have one, or initiate a new x402 payment to get a pack of requests.","exampleUseCases":[{"title":"Fetch current rates via MCP","prompt":"Use the rate-hub MCP endpoint to call the tools/list method and show me what rate data tools are available — pay with USDC on Base if needed."},{"title":"Reuse credit token for bulk queries","prompt":"I already have a rate-hub credit token from a previous payment — use it to make several JSON-RPC calls to the MCP endpoint and pull the latest rate information without paying again."},{"title":"Bootstrap x402 payment for MCP access","prompt":"I want to start querying the rate-hub API via its MCP interface. Walk me through the x402 payment flow on Base to get a credit token, then call the initialize method to set up my session."}],"resultDescription":"A JSON-RPC 2.0 response object containing the result of the requested MCP method call, along with HTTP headers including X-Credit-Token, X-Credit-Remaining, and PAYMENT-RESPONSE when a payment was processed. Errors are returned as 200 responses with JSON-RPC error payloads following MCP conventions.","failureModes":["402 response if no valid credit token and no payment signature provided","402 if credit token is spent or expired — must re-pay","402 if payment cannot be accepted (invalid signature, wrong amount, wrong scheme)","MCP-wrapped 200 with error body if JSON-RPC method is unknown or params are malformed","Network timeout if Base blockchain payment verification is slow"],"whenToPreferThis":"Choose this endpoint when you need to interact with rate-hub API capabilities through the standardized Model Context Protocol (MCP) JSON-RPC 2.0 interface and are operating in an x402-enabled environment that can handle USDC micropayments on Base. Prefer this over direct REST endpoints when your agent framework natively supports MCP tool discovery and invocation.","instructions":null,"reviewSummary":null,"reviewSummaryHighlights":null,"reviewSummaryConcerns":null,"reviewSummaryGeneratedAt":null,"activationCount":0,"lastUsedAt":null,"lastSuccessfullyRanAt":null,"lastHealthCheckAt":"2026-10-11T12:46:13.427Z","isFirstParty":false,"canonicalSlug":"rate-hub-api-mcp-endpoint-41fdc0d7"}