Twelve Data

What it is

Twelve Data is a market data API with unusually wide instrument coverage for its price: stocks, ETFs, forex, crypto, commodities, mutual funds, fixed income and around 5,000 indices, reachable over REST at api.twelvedata.com and streaming over WebSocket. Fundamentals sit on the same key — income statement, balance sheet, cash flow, dividends, splits, earnings estimates, analyst ratings — along with 100-plus server-side technical indicators, which is the part that saves you writing a ta-lib layer of your own.

Billing is by credits per minute rather than by request count, and credit weights are not uniform: a /time_series call costs 1 credit per symbol, an /income_statement call costs 100. Budget against the endpoints you will actually hit, not against the headline number.

Pricing

Individual plans run Basic (free), Grow from $29, Pro from $99 and Ultra from $329 a month; within each tier the price rises with the credit allowance, so Grow tops out at $79, Pro at $229 and Ultra at $999 for 10,946 credits a minute. Annual billing takes 17% off, students and startups 20%, and the discounts do not stack. Business plans are separate: Venture at $149, $299 or $499, Enterprise at $1,099, and Enterprise+ on quote.

The tier names hide the real ladder, which is licensing, not throughput, and the split is by who you are rather than what you do with the data. Individual plans are for individuals — the vendor requires a business plan for any company, team or fund, even when the data never leaves the office. Basic is non-display, Grow and above add internal display, external display starts at Venture and redistribution at Enterprise.

Data & coverage

The docs claim over a million instruments, but market count is plan-gated: 3 markets on Basic, 27 on Grow, 76 on Pro, all 85 on Ultra. History depth varies by instrument — /earliest_timestamp returns 1980-12-12 for AAPL daily bars.

Integrations

Official clients for Python, Node.js, Go, Java, R and a CLI; add-ins for Excel and Google Sheets; an MCP server, hosted by the vendor and open source in its own repository; and an OpenAPI spec to generate anything else from. The key goes in an Authorization: apikey header or, if you insist, a query parameter. /batch bundles requests and /api_usage reports your own quota back to you, which is the cheapest way to find out how much a screening loop actually costs.

Streaming is where the plan matters. The socket is wss://ws.twelvedata.com, and a key may hold three connections over the lifetime of the application — open a fourth and the oldest is dropped — with at most 100 client-side events and a 1 MB subscribe message. Full access begins at Pro for individuals and Venture for business; Basic and Grow are held to one connection and eight simultaneous symbols from the trial list.

Limitations

• No options chain endpoint and no market news endpoint. If either is on your list, this is the wrong provider.
• The free tier is licensed for evaluation and development only — it cannot legally back a production app, however small.
• Real-time outside the US is an add-on, not a tier. EU real-time requires Pro plus a data add-on; Australia is delayed.
• Fundamentals at 100 credits per symbol make the cheap plans impractical for screening work.
• Grow costs $29 to $79 and still has no usable WebSocket — its credits only stream trial symbols, so real streaming starts at $99.
• An individual plan does not cover a company, team or fund, however small and however internal the use; the vendor says the wrong tier is a terms-of-service problem, not a billing one.

Alternatives

Massive (formerly Polygon.io) if you need US tick data and nothing else; EODHD and Financial Modeling Prep for cheaper global end-of-day coverage. Compare the field against the rest of the market data APIs.