Market data API & MCP server for AI agents

A public, read-only JSON API for S&P 500 market data: market indicators, Fear & Greed, earnings, SEC filings, insider and Congress trades. No API key is required to start. OpenAPI 3.1 schema at https://quantustik.com/api/v1/openapi.json. This page is the reference documentation — every endpoint and every MCP client install snippet. For the quickstart, the free request limits and the flat $0.01 pay-per-request price, see the API storefront.

Endpoints

• GET /api/v1/earnings/{ticker} — Earnings calendar for one ticker: the next and last reporting dates, and how many days away the next one is.
• GET /api/v1/filings/8-k/feed — A dated, page-through history of 8-K filings (the reports a company must file when something material happens).
• GET /api/v1/filings/digest — Site-wide feed: most recent 8-K filings across the S&P 500 (TOP-100) universe.
• GET /api/v1/filings/digest/10-k — Site-wide feed: most recent 10-K annual reports across the S&P 500 (TOP-100) universe.
• GET /api/v1/filings/digest/{ticker} — 8-K Event Digest — recent 8-K filings for one ticker, AI-summarized.
• GET /api/v1/filings/feed — One dated, page-through history covering every SEC filing form we store.
• GET /api/v1/filings/language-diff/{ticker} — What changed in the language of one company's latest SEC filing, versus the comparable filing a year (or a quarter) earlier.
• GET /api/v1/financials/{ticker} — Latest-filed SEC financial facts with dates, provenance and data quality.
• GET /api/v1/insider/feed — Paginated, dated feed of persisted SEC Form 4 insider transactions
• GET /api/v1/insider/screener — S&P 500 screener: which top-100 tickers have notable insider activity now.
• GET /api/v1/insider/{ticker} — Insider Pulse — recent SEC Form 4 insider transactions for one ticker.
• GET /api/v1/institutional/feed — A dated, page-through feed of institutional 13F holdings — who owns what, and how much.
• GET /api/v1/institutional/{ticker} — What the big institutional investors and activist shareholders are doing in one ticker.
• GET /api/v1/market/correlations — Which S&P 500 stocks have moved together: trailing daily-return correlation.
• GET /api/v1/market/fear-greed — Fear & Greed index (latest cached value).
• GET /api/v1/openapi.json — OpenAPI 3.1 schema (machine-readable).
• GET /.well-known/quantustik.json — Capability manifest for AI agents.

MCP server for AI agents

Quantustik also runs a hosted MCP (Model Context Protocol) server at https://quantustik.com/mcp (streamable-HTTP, no API key required to start) so Claude and other MCP-compatible agents can call get_fear_greed, get_insider_pulse, get_filings_digest, get_earnings_calendar and related tools directly. The hosted endpoint is the only transport we operate: there is nothing to install and no local process to run. Every keyed response carries X-Quota-Remaining / X-Quota-Limit headers. Request limits are shared with the REST API:

Pay per request, no account

$0.01 per request, in USDC on Base, no signup, no key, no card. Call a route under /api/paid/v1 and the answer is an HTTP 402 that states the price and the payee. Pay it over the x402 protocol, send the signed proof in an X-PAYMENT header and repeat the request. The same price applies to every route; the live catalogue is the source for each route and its price.

A generic MCP client cannot pay. The hosted /mcp endpoint stays free; paying needs a wallet wrapper that speaks x402, and a plain MCP client has none.

Install in your MCP client

No API key is required to start — anonymous access is rate-capped at 1000 requests/hour per IP; a free key raises that to 5,000/day. Every client below points at the same hosted endpoint, https://quantustik.com/mcp.

Claude Code

claude mcp add --transport http quantustik https://quantustik.com/mcp

Claude Desktop / claude.ai

Settings → Connectors → Add custom connector, then paste https://quantustik.com/mcp.

ChatGPT (developer mode)

Settings → Connectors → Advanced → Developer mode, then add an app with MCP server URL https://quantustik.com/mcp.

Cursor

~/.cursor/mcp.json:

{
  "mcpServers": {
    "quantustik": {
      "url": "https://quantustik.com/mcp"
    }
  }
}

VS Code

.vscode/mcp.json:

{
  "servers": {
    "quantustik": {
      "type": "http",
      "url": "https://quantustik.com/mcp"
    }
  }
}

Cline

cline_mcp_settings.json:

{
  "mcpServers": {
    "quantustik": {
      "type": "streamableHttp",
      "url": "https://quantustik.com/mcp",
      "disabled": false,
      "autoApprove": []
    }
  }
}

LobeHub

Add a custom MCP server with URL https://quantustik.com/mcp from the LobeHub MCP marketplace.

Educational research only — not investment advice.