$0best free real-time entry
$199Massive full real-time SIP /mo
72EODHD MCP tools
800Twelve Data free credits/day
25Alpha Vantage free requests/day
TL;DR · best by use case
- **Best free real-time for prototyping:** Tiingo — real-time IEX quotes over WebSocket on the free plan (500 symbols/mo, 50 req/hr caps), and Alpaca's free IEX feed. Both are a subset of consolidated US volume, fine for research, not for execution.
- **Best free REST sandbox:** Finnhub's free tier (60 calls/min + free WebSocket, personal/non-commercial use). Massive Basic (5 calls/min, 15-min delayed, ~2 years of history) for historical work.
- **Cheapest full real-time SIP tape:** Alpaca Algo Trader Plus at $99/mo (needs an Alpaca brokerage account) and Massive Advanced at $199/mo. Massive Starter ($29) and Developer ($79) are unlimited-call but still 15-min delayed — the $199 cliff is where real-time actually starts.
- **Best value all-around:** EODHD — free plan, real-time from ~€29.99/mo, global coverage (150k+ tickers), and the most agent-ready surface in the category (official MCP server with 72 tools, OpenAPI 3.1, AI skills).
- **Best fundamentals bundle:** FMP from $22/mo (annual) and Twelve Data's credit model for indicators; Alpha Vantage has the richest indicator set but its free tier has shrunk to 25 requests/day.
- **Avoid for production:** scraped/unoffical Yahoo Finance endpoints — free, but gray-area ToS and rate-limit risk you cannot plan around.
## First, define "live"
Before picking a provider, pick your tier. There are four, and the price jumps between them are where most people get burned.
1. **End-of-day / historical.** Daily bars, often free or near-free. Fine for backtests and research, useless for anything time-sensitive.
2. **15-minute delayed.** The API is fast; the *data* is stale. Most "cheap" paid plans and every "unlimited calls" entry tier (Massive Starter/Developer, several Finnhub tiers) sit here.
3. **Real-time streaming.** Sub-second or streaming prints over WebSocket from the exchanges. This is the product traders mean by "live." It is where the pricing cliff lives: usually $99–$200+/month.
4. **Consolidated SIP / NBBO-grade.** The full tape across all US exchanges, often with OPRA options. Only matters for execution-quality decisions.
An agent that answers "what's TSLA doing right now?" needs tier 3. An agent that writes a weekly research memo needs tier 1. Paying for tier 3 when you need tier 1 is the most common overspend in this whole category.
## The free tier, ranked for real use
| Provider | Free tier | Real-time? | Best for |
|---|---|---|---|
| **Tiingo** | 500 symbols/mo, 50 req/hr, WebSocket | Yes — IEX real-time | Streaming prototype, light research |
| **Alpaca** | Free IEX feed + WebSocket | Yes — IEX real-time | Zero-cost streaming, if you accept an Alpaca account |
| **Finnhub** | 60 calls/min + WebSocket | Yes (basic endpoints) | Broad endpoint sampling, personal use |
| **Massive (ex-Polygon)** | 5 calls/min, ~2 yr history | No — 15-min delayed/EOD | Historical REST, sandboxing |
| **Twelve Data** | 800 credits/day, 8/min | Yes — US equities | Free daily quota for indicators |
| **FMP** | 250 calls/day, EOD | No — end-of-day | Fundamentals research |
| **Alpha Vantage** | 25 requests/day | No — delayed | Occasional lookups only |
The single best free real-time option is **Tiingo**: real-time IEX quotes stream over WebSocket on the *free* plan, no credit card, 500 unique symbols/month. IEX is a fraction of consolidated US volume — fine for dashboards and research agents, not for execution. **Alpaca** gives you the same IEX feed free if you're willing to hold an Alpaca account.
**Finnhub** remains the most generous free REST tier in the category — ~60 calls/min on basic endpoints plus a free WebSocket — with the explicit caveat that the free tier is for personal, non-commercial use. If you might commercialize, budget for a paid plan or get written approval first.
**Alpha Vantage**'s free tier has been ground down to **25 requests/day** (it was 100, before that 500). It still has the richest technical-indicator set in the market, and an official MCP server, but the free tier is now a taste, not a plan.
## Real-time streaming: where the cliff is
If your product or agent genuinely needs the live tape, the relevant comparison is tight:
- **Alpaca Algo Trader Plus — $99/mo.** Full SIP across US exchanges plus OPRA options, 10,000 calls/min, unlimited WebSocket. Requires an Alpaca brokerage account, which is either a feature (trading + data in one) or a dealbreaker (you don't want a brokerage).
- **Massive Advanced — $199/mo.** Real-time SIP for US stocks, unlimited API calls, flat-rate. This is Polygon's successor — Polygon rebranded to Massive on October 30, 2025; `api.polygon.io` and existing keys still work.
Everything below those two is delayed. **Massive Starter ($29/mo) and Developer ($79/mo)** both offer unlimited calls but remain 15-minute delayed — the most common misconception in the category is that $29 or $79 buys real-time. It does not. The single pricing cliff is the jump from $79 (delayed) to $199 (real-time).
For mid-tier real-time without the US-SIP price tag, **EODHD** (real-time from ~€29.99/mo on All-World), **Twelve Data** (real-time US/forex/crypto built into credits), and **Finnhub** (paid from $49.99/mo) cover global markets at a lower entry cost than a full SIP tape.
## Best for AI agents: the MCP and structure story
The market-data category changed in the last year because agents entered it. The APIs that win agent workloads are not the ones with the best dashboards — they are the ones that hand a model structured, schema-described data with minimal ceremony.
**EODHD is the clear leader for agents.** It ships an official MCP server with 72 specialized tools, an AI skills adapter (72 endpoints, stdlib-only Python) for Claude Code and Codex-style agents, an OpenAPI 3.1 spec covering 74 endpoints for function-calling and code generation, and a custom GPT for the API. 150,000+ tickers, 60 exchanges, forex, crypto, ETFs, indices. It is built to be the data layer of an agent, not a charting site's backend. Free plan to start, paid from $19.99/mo (€19.99/mo All-World).
**Massive** is the low-latency agent pick for US-centric work — tick-level trades, quotes, aggregate bars, up to 20+ years of history, WebSocket streaming, and a clean REST surface. The MCP server is well-designed for financial workflows. US-centric, and real-time costs the $199/mo tier.
**Alpha Vantage** has an official MCP server and the best technical-indicator coverage, but its free tier (25/day) and $49.99+/mo paid entry make it a poor default for token-hungry agent loops — every agent retry and multi-hop query burns your daily quota fast.
**Tiingo** is the lightweight agent value: clean data, a WebSocket for live streams, an MCP with prompt templates, and very low cost. Not the deepest dataset, but the cheapest floor that is real-time.
**Twelve Data** is a strong REST default for indicators and cross-asset coverage with its credit model — every endpoint has a "data weight," and a single call can carry multiple symbols, which plays well with batch-oriented agents.
## Historical and fundamentals
For backtests, financial research, and fundamentals-heavy agents:
- **FMP (Financial Modeling Prep):** free 250 calls/day; Starter **$22/mo** (annual) with 300 calls/min and 5-year history; Premium **$59/mo** (30-year history, UK/Canada, intraday); Ultimate **$149/mo** (global, earnings transcripts, 13F, 1-min intraday). Best fundamentals-per-dollar in the category.
- **Twelve Data:** 800 free credits/day; paid from **$29/mo** (Grow) scaling to $99–$329 (Pro/Ultra). The credit model means indicator-heavy calls cost more — budget accordingly.
- **EODHD:** fundamentals feed €59.99/mo as an add-on; deep history included in higher tiers.
- **Alpha Vantage:** $49.99–$249.99/mo tiers that buy *throughput* (requests/minute), not new data. 2,500+ technical indicators included.
## What not to build on
**Unofficial/scraped Yahoo Finance endpoints** (the `query1.finance.yahoo.com` JSON endpoints) are still everywhere in tutorials. They are free, but: no SLA, no ToS guarantee, rate-limit bans that appear and vanish without notice, and a structural risk that Yahoo breaks the format at any time. Fine for a personal weekend project; a production agent built on it is a pager rotation waiting to happen. Also note **IEX Cloud shut down in August 2024** — the many tutorials pointing at `cloud.iexapis.com` are dead links; Tiingo and Alpaca are the natural heirs.
## The bottom line
- **Prototype free with real-time:** Tiingo or Alpaca IEX feeds.
- **Cheapest production real-time tape:** Alpaca Algo Trader Plus ($99/mo, brokerage required) or Massive Advanced ($199/mo).
- **Best all-around + agent-ready:** EODHD — the strongest MCP/agent surface, global coverage, real-time from ~€29.99/mo.
- **Best free REST sandbox:** Finnhub (personal use).
- **Best fundamentals value:** FMP from $22/mo.
- **Best indicator set:** Alpha Vantage, but only if you pay.
And when an agent is the consumer, weight the MCP server, the structured-output story, and the WebSocket over the per-month headline. A market-data API your agent can call without a custom integration layer is worth more than the one that is $10 cheaper and requires one.
## FAQ
### What is the best free API for real-time stock data in 2026?
Tiingo's free plan streams real-time IEX quotes over WebSocket (500 symbols/month), and Alpaca offers a free IEX feed — both are subsets of consolidated US volume, fine for research and dashboards but not execution. Finnhub's free tier (~60 calls/min plus WebSocket) is the best free REST sandbox, restricted to personal/non-commercial use.
### Is Polygon.io still available in 2026?
Polygon rebranded to **Massive** on October 30, 2025. The product, `api.polygon.io` endpoints, and existing API keys still work; pricing and docs now live at massive.com. The free Basic plan is 5 calls/min with 15-minute-delayed data and ~2 years of history; full real-time SIP starts at the $199/mo Advanced tier.
### What is the cheapest way to get real-time market data?
For a full consolidated US tape, Alpaca Algo Trader Plus at $99/mo (requires an Alpaca brokerage account) is cheapest, followed by Massive Advanced at $199/mo. For non-US or lower-frequency real-time, EODHD (from ~€29.99/mo) and Twelve Data (credits from $29/mo) are cheaper entry points.
### Which financial data API is best for AI agents?
EODHD leads for agents: an official MCP server with 72 tools, an AI-skills adapter for Claude Code/Codex, OpenAPI 3.1, and global coverage. Massive is the low-latency US pick; Tiingo is the cheap lightweight option with WebSocket real-time; Alpha Vantage has an official MCP server and the richest indicators but a weak free tier for agent loops.
### Why does Alpha Vantage's free tier feel so limited?
Alpha Vantage has cut its free tier from 500 requests/day historically to 100, then to **25 requests/day** in 2026, with a 5/minute throttle. Paid tiers ($49.99–$249.99/mo) buy requests-per-minute throughput, not new data. It is best used for occasional lookups or indicator-heavy calls, not agent-scale loops.
### Can I use Yahoo Finance's unofficial API in production?
Technically yes, but you shouldn't: no SLA, no ToS guarantee, unpredictable rate-limit bans, and the format can change without notice. For a production agent, any of the paid providers above is cheaper than the pager.