Comparison · Market & Financial Data

Market data MCP servers compared: Alpha Vantage, Polygon.io and Finnhub

Three of the market data MCP servers in this directory cover overlapping ground, and picking between them is mostly a question of which task you are handing to an AI assistant. This page sets them side by side using the same listing data the directory and our MCP tools serve — nothing here is a paid placement, and none of it is an endorsement.

Whichever you connect, start with a read-only API key and confirm what the key is entitled to before pointing an assistant at client work.

At a glance

Server	Status	Auth	Hosting	Covers
Alpha Vantage	Official	API key	Remote	Stocks, ETFs, options, forex, crypto, commodities, fundamentals, technical & economic indicators via natural language.
Polygon.io	Official	API key	Both	Tick-level US equities data, WebSocket streaming and low-latency quotes.
Finnhub	Official	API key	Remote	Real-time quotes, fundamentals, earnings calendar and news with sentiment scores.

Status, auth, hosting and coverage are reproduced from each server's directory listing, which reflects publisher documentation at the last review. Vendor claims are labelled as such and are not independently verified.

Where each one is the better answer

Alpha Vantage

Best for

Breadth in one place — equities, ETFs, options, forex, crypto, commodities, fundamentals, and technical and economic indicators, queried in plain language.

Watch for

The API key travels in the endpoint URL, so treat that endpoint as a secret and rotate it if it is shared. Free-tier rate limits make it unsuitable for anything time-critical.

Listing and connection details →

Polygon.io

Best for

Depth on US equities — tick-level history, WebSocket streaming and low-latency quotes. The one to reach for when the question is about intraday price behaviour rather than a company profile.

Watch for

Tick data and streaming sit on higher-priced plans; the coverage a given key returns depends on the subscription behind it, not on the server.

Listing and connection details →

Finnhub

Best for

Advisor-facing context — real-time quotes alongside fundamentals, an earnings calendar and news with sentiment scores, so a single question can cover 'what moved and why'.

Watch for

News sentiment is a vendor-computed score, not an independent assessment. Never let a model present a sentiment number as an investment view.

Listing and connection details →

Endpoints and install commands are not repeated here — take them verbatim from each server's listing page, which is the version we keep current.

By advisor task

Intraday quote for a client call: All three return a current quote. Polygon.io is the one built for low latency; Alpha Vantage and Finnhub are fine when a short delay does not matter.
Fundamentals and ratios for a holding review: Alpha Vantage and Finnhub both serve fundamentals. Polygon.io is priced and shaped around price data, not company financials.
Backtesting or intraday history: Polygon.io. Tick-level history is the differentiator here; the other two are not designed for it.
Earnings dates and news around a position: Finnhub — the earnings calendar and scored news feed are its distinguishing tools.
Macro or FX context in a market commentary: Alpha Vantage, which covers forex, commodities and economic indicators in the same server.

Before you connect any of them

Start with a read-only key. None of these three needs write access to do the work described above.
What a key returns depends on the plan behind it. A tool call that fails or returns thin data is usually an entitlement question, not a broken server.
Market data delivered through an assistant can be paraphrased, rounded or interpolated by the model. Treat figures pulled into a client-facing document as needing a check against the source.
Listings in this directory are informational. They are not endorsements, security reviews, or investment advice.

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