Massive, the company formerly called Polygon.io, sells market data the way an exchange does: trades, quotes, aggregates and WebSockets for stocks, options, FX and crypto. Its stocks plans carry no economic data at all. If you came for the tape, stay. If you came for the print, you are in the wrong aisle.
Massive is a price-data API and a good one, from $29 a month for delayed stock data to $199 for real time, with a free end-of-day tier. None of the stocks plans list a calendar, Treasury yields or a release. Helious is the other half: every US release scored on print, the calendar with the actual the second it lands, Treasury auctions read within seconds, the curve with its regime, and an MCP server. From a free key, $14.99 on Starter, $39.99 on Pro.
| Helious | Massive (Polygon.io) | |
|---|---|---|
| Monthly price for the data a macro trader needs | Free key $0; Starter $14.99; Pro $39.99 a month | Stocks: Starter $29, Developer $79, Advanced $199 a month |
| Cost per year | About $180 on Starter or $480 on Pro paid monthly, 25% off paid yearly | $348 to $2,388 paid monthly; 20% off yearly |
| Free tier | Yes, 100 credits a month on a free key, no card | Yes, 5 calls a minute, end of day, 2 years |
| Economic calendar with forecast, prior and live result | Yes, every US release with forecast, prior and the actual the second it lands | Not on the stocks plans |
| Releases scored on print, in standard deviations | Yes, every US release, against its own history | No |
| Treasury auction results with the tail and bidders | Yes, within seconds: tail, bid to cover, bidder split and a verdict | Not covered |
| Treasury curve and regime | Yes, 3 month bill to 30 year bond, 2s10s, and the regime named | Not on the stocks plans |
| Answers open with a plain sentence | Yes, every answer opens with the finished sentence, then the numbers | No, numbers only |
| MCP server for AI agents | Yes, 24 tools at one address, no glue code | A listed server, marked experimental |
| History | 7 days free, 12 months Starter, 24 months Pro, 10 years Ultimate | 5, 10 or 20+ years of prices by plan |
| Calls a minute | 60 free, 90 Starter, 120 Pro, 300 Ultimate, per key | Unlimited on paid plans |
| Live stream | Yes, a WebSocket on Pro and Ultimate | Yes, WebSockets on Advanced |
| Redistribution | Personal on Free to Pro; Ultimate at $99 allows redistribution | Individual use; business plans sold separately |
Go with Massive (Polygon.io) if you need the tape: trades, quotes, aggregates and WebSockets for stocks or options, and the economic calendar is somebody else’s job.
Go with Helious if the event you trade is the print or the auction, you want it read and scored as it lands, and you want your AI to read it too.
There is a longer piece on what is the best financial news source if you want the whole category. Or go and look at the live news feed, the economic calendar and the Treasury auction results.
Competitor names are the trademarks of their respective owners. Prices shown are approximate list prices as of October 2026 and change without notice. Check each provider for current pricing. This is our own view of the market, offered as general information and not financial advice.
