Guide

What is a financial data API?

A financial data API is a documented interface that returns market and company data - quotes, financial statements, SEC filings, news, and calendars - so software can read markets without scraping a website. Teams use REST for request/response, WebSockets for push updates, and MCP so AI assistants call typed tools instead of inventing numbers.

What it usually includes

A useful financial data API covers more than a last price. Typical payloads include company identifiers, OHLCV or snapshot quotes, income/balance/cash-flow rows, SEC filing metadata, earnings dates, and news. Vantafin also exposes a stock screener with 80+ metrics across 12K+ US equities and 23 MCP tools for agents.

REST vs WebSocket vs MCP

AccessUse it when
RESTYou pull a quote, filing list, or screener row on demand.
WebSocketYou want news, filings, or quotes pushed as they happen (Vantafin: Ultimate).
MCPClaude, Cursor, or another agent should call typed tools instead of scraping.

How to start with a financial data API

  1. 1. List the fields you need Write down quotes, filings, financials, news, or screener rows so you do not buy the wrong API.
  2. 2. Choose REST, WebSocket, or MCP REST fits dashboards and batch jobs. WebSocket fits live news and filings. MCP fits Claude, Cursor, and other agents.
  3. 3. Create a Vantafin account Start on Free to browse profiles, then upgrade to Pro when you need an API key.
  4. 4. Create an API key On Pro or Ultimate, open Settings, create a key, and keep it off the client.
  5. 5. Make one verified request Call a single documented route or MCP tool and compare the payload to the company profile in the app.

Public Vantafin facts: 20K+ entities, SEC filings since 1994, live quotes on 9,000+ tickers on Pro. See pricing and alternatives.

Frequently asked questions

What is a financial data API?

A documented HTTP, stream, or MCP interface that returns quotes, fundamentals, filings, and related market datasets so applications and AI assistants do not scrape websites.

How is a financial data API different from a research website?

A website is for humans. An API is for software. Vantafin ships both: the same books in the browser and over REST, WebSocket, and MCP.

When should I use REST vs WebSocket vs MCP?

REST for on-demand quotes, filings, or screener rows. WebSocket when news or filings should push as they happen (Vantafin: Ultimate). MCP when Claude, Cursor, or another agent should call typed tools instead of scraping.

What does Vantafin include in its API?

Quotes, company profiles, financials, SEC filings since 1994, transcripts, news, ownership, a screener with 80+ metrics, and 23 MCP tools. WebSocket streaming is on Ultimate.

Do I need Ultimate for API access?

No. REST and MCP are on Pro ($25/mo or $20/mo annual). Ultimate ($50/mo or $40/mo annual) adds WebSocket and higher limits. See pricing.

Is scraping a website a financial data API?

No. Scraping breaks, often violates terms, and is not documented. A financial data API has auth, schemas, and a contract you can put in production.

How do I verify an API response?

Call one documented route or MCP tool, then open the same ticker in the Vantafin app and compare the payload to the profile. If you cannot open the source, do not treat the number as a fact.

Where else should I compare Vantafin?

The alternatives hub and the vs pages (Alpha Vantage, Finnhub, Yahoo Finance, TradingView, Koyfin, Bloomberg, Seeking Alpha). Plan limits live on pricing.

Ready to invest without the price tag?

Free to start. $20 or $40 a month unlocks live data, AI chat, and full API access.