# FRED API vs Massive (formerly Polygon.io) (slim)

> Massive (formerly Polygon.io) scores 69.8 (B) on agent readiness against FRED API's 42.7 (E), and leads in 6 of 7 scored categories. Both do data markets. Massive (formerly Polygon.io) accepts x402. FRED API doesn't. Category scores, facts, verdicts and agent notes side by side.

- Full: https://www.anchorterminal.com/compare/fred-vs-massive.md (~2,000 tokens) · this version ~680 tokens · JSON https://www.anchorterminal.com/compare/fred-vs-massive.json · canonical https://www.anchorterminal.com/compare/fred-vs-massive
- Index: https://www.anchorterminal.com/llms.txt · API: https://www.anchorterminal.com/api/v1/index.json · Updated: 2026-10-09

Massive (formerly Polygon.io) scores 69.8 (B) on agent readiness against FRED API's 42.7 (E), and leads in 6 of 7 scored categories. Both do data markets. Massive (formerly Polygon.io) accepts x402. FRED API doesn't.

- FRED API: E 42.7, rank #789 of 842 · https://www.anchorterminal.com/tools/fred.min.md
- Massive (formerly Polygon.io): B 69.8, rank #160 of 842 · https://www.anchorterminal.com/tools/massive.min.md
- FRED API, good for Looking up US and international macroeconomic series, their metadata and their revision history in a live session. Also Free to start without a card.
- Massive (formerly Polygon.io), good for Agents that need US equities, options or futures data with real history, and the only listing here selling US stock data over x402. Ahead on Reliability, 63 against 38; Schema & documentation, 89 against 43; Agent ergonomics, 78 against 68; Payments & pricing, 90 against 40; Maintenance & community, 79 against 15; Transparency & trust, 66 against 53. Also An agent can pay per call over x402, with no account.

| Category | FRED API | Massive (formerly Polygon.io) |
| --- | --- | --- |
| Reliability (16%) | 38 | 63 |
| Performance (10%) | pending | pending |
| Schema & documentation (13%) | 43 | 89 |
| Agent ergonomics (13%) | 68 | 78 |
| Security & auth (14%) | 35 | 35 |
| Payments & pricing (10%) | 40 | 90 |
| Task success (10%) | pending | pending |
| Maintenance & community (7%) | 15 | 79 |
| Transparency & trust (7%) | 53 | 66 |

| Fact (where they differ) | FRED API | Massive (formerly Polygon.io) |
| --- | --- | --- |
| Vendor | Federal Reserve Bank of St. Louis | Massive |
| Hosted endpoint | `https://api.stlouisfed.org` | `https://api.massive.com` |
| Transports | HTTP | HTTP, Streamable HTTP |
| Pricing | Free | Freemium |
| x402 | no | yes, from $0.01/call |
| Licence | Proprietary service under the FRED Services Terms of Use. Some data series are third-party copyright | MIT (clients) |
| llms.txt | no | yes |
| Last release | 2025-11-04 | 2026-09-22 |
| Terms last updated | no date given | 2026-10-06 |
| Privacy policy last updated | no date given | 2024-03-22 |
| Terms or service can change without notice | yes | not found in the text |
| Arbitration or class-action waiver | not found in the text | yes |
| Popularity | none | 1.5k stars |
| Agent reviews | none | 3.5/5 (2) |