The short answer

For US equities at retail scale in 2026, Polygon.io Stocks Advanced ($199/mo) wins flat-rate real-time, Alpaca free IEX is the zero-cost paper-trading default, Tiingo Power ($50/mo) wins long-horizon EOD plus fundamentals, and Databento is the only realistic tick and L2 source but bills metered.

For US equities at retail scale in 2026: Polygon.io Stocks Advanced ($199/mo) wins for most flat-rate real-time workloads. Alpaca free IEX is the correct default for paper-trading research if you can tolerate partial volume. Tiingo wins for long-horizon research built on EOD + fundamentals at $10/mo. Databento wins for tick + L2, but metered pricing scales aggressively — model it before committing. FMP and Alpha Vantage sit in "budget with caveats" territory. Full pricing tiers and a live scenario calculator: /data-vendor-tco/.

Methodology

All pricing reflects list rates on vendor pricing pages as of 2026-06-12. Enterprise + negotiated tiers are out of scope. Scenarios: small (≤50 symbols), medium (~500), large (~2,000), all US equities (~10,000). Resolutions tested: daily, 1-minute, 1-second, tick, L2. See /methodology/data-vendor-tco/ for the full rate table, assumptions, and limitations.

The headline table

Vendor Cheapest tier w/ real-time Monthly Resolutions Options Futures
Polygon.io Stocks Advanced $199 daily → tick no (separate Options product, $199 Advanced) no (separate Futures product, $199 Advanced)
Alpaca Algo Trader Plus $99 daily → tick yes no
Databento Metered ~$125 (medium-univ, minute) daily → L2 limited yes
Tiingo Power $50 daily + minute no no
FMP Ultimate $79 daily → second no no
Alpha Vantage Premium 600 $199.99 daily → second no no
Alpaca (free tier) IEX-only $0 daily + minute no no

Numbers reflect list pricing as of 2026-06-12. Verify on the vendor page before committing. Full tier-by-tier breakdown for the Polygon.io row above: Polygon.io Pricing Plans 2026; options pricing is covered in Polygon.io Options API Pricing 2026, and Databento vs Polygon.io 2026 goes deeper on the tick + L2 trade-off.

Who wins for which profile

Profile: paper-trading researcher, zero budget

Alpaca free IEX + Tiingo Starter ($10/mo) for fundamentals. Total: $10/mo. Limitations: IEX is a subset of consolidated volume (roughly 2-5%), so backtests on it are partial. Fine for directional idea generation; not fine for execution-sensitive strategies.

Profile: swing trader, ~500 symbols, medium-frequency

Polygon.io (now Massive) Stocks Advanced ($199/mo). Real-time across the full SIP tape. Unlimited API calls. No options on this tier — options ship as a separate Options Advanced product at $199/mo (the same price as Stocks Advanced, not a premium), so a stocks-plus-options stack is two subscriptions. If you'd rather pay once, pivot to Alpaca Algo Trader Plus ($99/mo), which bundles options, or layer on CBOE direct.

Profile: fundamental investor, long-horizon

Tiingo Power ($50/mo). EOD + fundamentals + news in one tier. Limitations: no real-time, no options. Pair with FMP Starter ($14/mo) if you need earnings call transcripts.

Profile: microstructure / HFT-curious retail

Databento metered (~$100-500/mo depending on universe + resolution). Only realistic option for tick + L2 at retail scale. Budget carefully — metered billing punishes speculative re-queries. Verify with Databento's quoting tool before subscribing.

Profile: options-first retail trader

Alpaca Algo Trader Plus ($99/mo) or tastytrade API. Polygon.io does not bundle options on the Stocks Advanced tier; it's a separate Options Advanced subscription priced at $199/mo — the same as Stocks Advanced, so you pay it on top, not instead. See Polygon.io Options API Pricing 2026 for the full options ladder.

Gotchas + caveats

  • IEX tape vs SIP tape. Alpaca's free tier is IEX-only. IEX handles roughly 2-5% of total US equity volume. For low-frequency research on large-cap names, IEX is fine. For microstructure, small-caps, or anything execution-sensitive, you need SIP — which means paying for it.
  • Databento's metered pricing. The calculator models typical retail spend at ~$125/mo for a medium universe on minute bars. Real spend varies ±50% depending on schema, delivery mode, and query patterns. Sandbox free credits are limited; production spend scales.
  • Polygon.io's "unlimited API calls". Rate-limited by HTTP connection, not quota. Parallel streaming + bulk historical pulls can still get you throttled.
  • Alpha Vantage's rate limits. Premium 75 allows 75 calls/minute. Premium 600 allows 600. For a 500-symbol scan, you'll hit that limit without batching.
  • FMP's historical depth. Starter limits to 5 years. Premium removes the cap. Check your backtest window before subscribing.
  • Tiingo Power list price is unconfirmed. Tiingo's pricing page is JS-rendered and not machine-readable; public sources disagree on the Power tier ($30 vs $50/mo, unconfirmed as of 2026-05-25). Treat the $50 figure above as an upper-bound estimate and verify on the vendor page.

The MCP angle

If your research stack uses MCP, consider vendor MCP server coverage:

  • Polygon.io ships an official MCP server (read-only, Apache-2.0). Grade A in the Finance MCP Directory.
  • Alpaca ships MCP V2 with 61 actions including execution. Grade A. The idempotency support is a distinguishing feature vs community alternatives.
  • Databento has a community MCP server (grade B) — read before wiring to production.
  • Tiingo, FMP, Alpha Vantage do not ship official MCP servers. Community wrappers vary in quality.

What we'd recommend today

The combo that shows up repeatedly in retail algo threads:

  • Data: Polygon Stocks Advanced (real-time) or Alpaca Algo Trader Plus (if you also trade on Alpaca)
  • Fundamentals: Tiingo Power
  • Options (if needed): Alpaca options surface (included in Algo Trader Plus)
  • MCP layer: Alpaca MCP V2 + Polygon MCP (both grade A)

Total: $250–300/mo for a mature single-operator stack. Budget workers can start at $10–50/mo (Tiingo + Alpaca free) and scale up as the strategy demands it.

Calibrate for your exact workload

The flat table above is a starting point; your actual cheapest vendor depends on your universe, resolution, and real-time need. The Data-Vendor TCO Calculator takes those inputs and returns a ranked list of qualifying vendors for your scenario. Use it before subscribing.

This is the market-data entry in the broker-and-data-vendor series: six data vendors (Polygon, Databento, Alpaca, Tiingo, FMP, Alpha Vantage) on price, resolution, and coverage — distinct from the broker decision. Read alongside:

Sources

Editorial independence

AI Fin Hub Research maintains editorial independence across sponsor relationships. Vendor placements in tools and comparators are not altered by sponsor payments. Disclosures at /sponsor-disclosure/.

Frequently asked questions

What's the cheapest market data API for a paper-trading researcher under $15/month?
Alpaca's free IEX tier ($0) plus Tiingo Starter ($10/mo) for fundamentals, $10/mo total. The caveat is that IEX covers only about 2-5% of consolidated volume, so backtests on it are partial. Fine for directional idea generation, not for execution-sensitive strategies, which need the full SIP tape.
Which market data API fits a 500-symbol swing-trading agent that needs real-time?
Polygon.io Stocks Advanced at $199/mo: real-time across the full SIP tape with unlimited API calls (rate-limited by connection, not quota). It carries no options coverage, so if you also need options, pivot to Alpaca Algo Trader Plus ($99/mo) or layer on a dedicated options feed.
Is Databento worth it over a flat-rate vendor for tick and order-book data?
For tick and L2 at retail scale it is effectively the only realistic option, but metered pricing scales aggressively, around $125/mo for a medium universe on minute bars and varying plus or minus 50% by schema and query pattern. If you only need daily-to-minute bars, Polygon ($199/mo) or Tiingo Power ($50/mo) is more predictable. Model it first.