Quickstart

This page takes you from nothing to a first successful request on each of the three ways to reach xfinlink: the Python client, the REST API and the MCP server. Every sample below uses a date window inside the last 12 months, so it works on every plan, including Free.

1. Choose how you connect

2. Get your API key

Create a free account at https://xfinlink.com/signup. No card is needed. The dashboard at https://xfinlink.com/dashboard creates your key; copy it with the copy button. Every sample on this page shows YOUR_API_KEY where your key goes.

A key is xfl_ followed by 32 lowercase hexadecimal characters, 36 characters in all. Keep it secret: anyone holding it can spend your plan's quota. Authentication covers the key format and where to send it.

A Free key allows 1 ticker per request, the last 12 months of history, and 100 requests a day with at most 40 in one clock hour. Plans and limits compares every plan.

3. Install the Python client

The client needs Python 3.9 or later.

$pip install -U xfinlink

Check the installed version with the command-line tool that ships with the package.

$xfinlink version

0.13.1

4. Make your first call in Python

Set your key, then ask for five days of Apple prices.

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6import xfinlink as xfl

xfl.set_api_key("YOUR_API_KEY")

df = xfl.prices("AAPL", start="2026-09-21", end="2026-09-25")
print(df[["ticker", "date", "close", "volume", "return_daily"]])

  ticker       date   close    volume  return_daily
0   AAPL 2026-09-21  338.98  34999200      0.008479
1   AAPL 2026-09-22  339.75  40711800      0.002272
2   AAPL 2026-09-23  337.02  31658800     -0.008035
3   AAPL 2026-09-24  335.92  24733100     -0.003264
4   AAPL 2026-09-25  341.07  30002500      0.015331

close is in USD per share, volume is a count of shares, and return_daily is a decimal ratio, not a percentage: 0.015331 is a 1.5331% gain.

Instead of calling set_api_key, you can export the key before you start Python. The client reads XFINLINK_API_KEY first, then XFL_API_KEY.

$export XFINLINK_API_KEY=YOUR_API_KEY

5. Call the REST API with curl

Send the same request over HTTP. Pass the key in the X-API-Key header.

$
curl -H "X-API-Key: YOUR_API_KEY" \
  "https://api.xfinlink.com/v1/prices/AAPL?start=2026-09-21&end=2026-09-25"

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55{
  "data": [
    {
      "entity_id": 10003635,
      "ticker": "AAPL",
      "entity_name": "APPLE INC",
      "gics_sector": "Information Technology",
      "date": "2026-09-21",
      "open": 335.28,
      "high": 339.64,
      "low": 333.05,
      "close": 338.98,
      "adj_close": 338.98,
      "volume": 34999200,
      "return_daily": 0.008478862344926119,
      "return_spans_unpriced": false,
      "exchange_code": "NASDAQ",
      "price_basis": "trade",
      "shares_outstanding": 14594180000,
      "shares_as_of": "2026-07-17",
      "shares_source": "filing",
      "shares_stale": false,
      "split_ratio": null,
      "split_ratio_suspect": false,
      "dividend": null,
      "dividend_type": null,
      ...
    },
    ...
  ],
  "meta": {
    "tickers_requested": ["AAPL"],
    "tickers_resolved": {"AAPL": 10003635},
    "tickers_unresolved": [],
    "resolved_via": {"AAPL": "security_alias"},
    "entity_id_grain": "security",
    "adj_close_basis": "split",
    "segments": [
      {"entity_id": 10003635, "entity_name": "APPLE INC", "first_date": "2026-09-21", "last_date": "2026-09-25"}
    ],
    "interval": "1d",
    "data_through": "2026-09-25",
    "count": 5,
    "limit": 1000,
    "has_more": false,
    "next_cursor": null,
    "knowledge_time": "2026-09-26T12:48:18Z",
    "as_of": "2026-09-25",
    "freshness": [
      {"dataset": "prices", "through": "2026-09-25", "promoted_at": "2026-09-21T14:19:25Z"},
      {"dataset": "price_adjustments", "through": "2026-09-25", "promoted_at": "2026-09-18T19:07:02Z"},
      {"dataset": "shares_outstanding", "through": "2026-09-23", "promoted_at": "2026-09-24T08:30:33Z"}
    ]
  }
}

Prices are in USD per share and shares_outstanding is a whole count of shares. The Python client returns the same rows as a pandas DataFrame.

6. Connect an AI assistant

The MCP server lets Claude, ChatGPT, Cursor and other MCP clients call xfinlink for you. Add this URL as a custom connector, or remote MCP server, in your client. It uses the Streamable HTTP transport.

https://api.xfinlink.com/mcp?api_key=YOUR_API_KEY

The URL contains your key, so treat it as a secret. In Claude Code, one command adds the server; run /mcp inside Claude Code afterwards to check that it is connected.

$claude mcp add --transport http --scope user xfinlink "https://api.xfinlink.com/mcp?api_key=YOUR_API_KEY"

Setup for Claude, ChatGPT, Claude Desktop, VS Code and Cursor is on MCP server. Then ask a question in plain English.

What were Apple's daily closing prices from 21 to 25 September 2026?

The assistant calls the get_prices tool. The tool result is the same JSON the REST API returns.

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25{"tool": "get_prices", "arguments": {"ticker": "AAPL", "start": "2026-09-21", "end": "2026-09-25"}}
{
  "data": [
    {
      "entity_id": 10003635,
      "ticker": "AAPL",
      "entity_name": "APPLE INC",
      "gics_sector": "Information Technology",
      "date": "2026-09-21",
      "open": 335.28,
      "high": 339.64,
      "low": 333.05,
      "close": 338.98,
      ...
    },
    ...
  ],
  "meta": {
    "tickers_requested": ["AAPL"],
    "tickers_resolved": {"AAPL": 10003635},
    ...
    "count": 5,
    ...
  }
}

7. Read what came back

Every response pairs the rows in data with a meta block.

• data holds one row per trading day. entity_id 10003635 identifies Apple's common share class. Tickers and entities explains how an entity_id differs from a ticker.
• meta.tickers_resolved shows which entity each ticker you sent was matched to.
• meta.count is the number of rows, and meta.has_more tells you whether another page exists.
• meta.freshness shows, for each dataset behind the response, the last date it covers.

Response metadata explains every meta field.

Next steps

• Authentication

  Send your key in a header or a query parameter, and see which endpoints answer without one.

• Plans and limits

  Compare what Free, Pro, Max and Redistribution allow per request and per day.

• Response metadata

  Read meta to see how tickers were resolved and how current the data is.

• Tickers and entities

  Use entity_id to follow one company across ticker changes and share classes.

• Prices

  Every parameter, field and plan difference of the prices endpoint.

• MCP server

  Set up Claude, ChatGPT, Cursor and other assistants step by step.