Massive (formerly Polygon.io)

Use in your agent

Load Massive (formerly Polygon.io) daily bars into pandas and Parquet. Checked against the provider's documentation on Oct 29, 2026.

Access

• Sign up or log in at massive.com and copy your API key from the Dashboard (the free plan is Stocks Basic).
• Send the key as Authorization: Bearer <key> or as ?apiKey=<key>. Keep it out of code; the snippet reads MASSIVE_API_KEY.

Request

curl -H "Authorization: Bearer $MASSIVE_API_KEY" 'https://api.massive.com/v2/aggs/ticker/AAPL/range/1/day/2026-09-29/2026-10-28?adjusted=true&sort=asc&limit=120'

Format

JSON: ticker, adjusted, queryCount, resultsCount, status, results (o, h, l, c, v, vw, n, t) and next_url when there is another page. t is the Unix millisecond start of the bar.

Load into pandas and Parquet

Needs Python 3 with requests, pandas and pyarrow.

"""Massive (formerly Polygon.io) daily bars for one stock -> pandas -> Parquet. Free key required."""
import os
import requests
import pandas as pd

session = requests.Session()
session.headers["Authorization"] = f"Bearer {os.environ['MASSIVE_API_KEY']}"  # key from your Massive dashboard
url = "https://api.massive.com/v2/aggs/ticker/AAPL/range/1/day/2025-01-01/2026-10-28"
params = {"adjusted": "true", "sort": "asc", "limit": 50000}
rows = []
while url:
    r = session.get(url, params=params, timeout=30)
    r.raise_for_status()
    body = r.json()
    rows += body.get("results", [])
    url, params = body.get("next_url"), None   # next_url already carries the query; the header carries the key

df = pd.DataFrame(rows).rename(columns={"o": "open", "h": "high", "l": "low", "c": "close",
                                        "v": "volume", "vw": "vwap", "n": "transactions"})
df["date"] = pd.to_datetime(df.pop("t"), unit="ms", utc=True)   # t = start of the bar, Unix milliseconds
df.to_parquet("massive_aapl_daily.parquet", index=False)
print(len(df), "rows", df["date"].min(), "to", df["date"].max())

Not run: it needs a personal API key.

Limits

• Free Stocks Basic: 5 API calls a minute, 2 years of history, end-of-day data.

Quirks

• Results are split-adjusted by default; pass adjusted=false for raw prices.
• limit caps the base aggregates used to build the bars (default 5,000, maximum 50,000); follow next_url for more.
• Without a key the API answers HTTP 401 "API Key was not provided" (observed 2026-10-29).

Terms and attribution

• Stocks Basic is a personal-license plan. Massive's Individuals terms cover personal, individual and non-business use of products labeled Individual Use; business or commercial use falls under its Businesses terms and plans.

Sources

• https://massive.com/docs/rest/quickstart: “Visit your Dashboard to find your API key.”
• https://massive.com/pricing: “5 API Calls / Minute”
• https://massive.com/pricing: “2 Years Historical Data”
• https://massive.com/pricing: “End of Day Data”
• https://massive.com/legal/terms: “The Massive for Individuals Terms of Service apply to your personal, individual, and non-business use of any service or product labeled for "Individual Use".”
• https://massive.com/docs/rest/stocks/aggregates/custom-bars: “Max 50000 and Default 5000.”
• https://massive.com/docs/rest/stocks/aggregates/custom-bars: “The Unix millisecond timestamp for the start of the aggregate window.”