QuantConnect

What it is

Two delivery forms of one product. LEAN is the event-driven engine that does the work — C# with a Python API, Apache-2.0, self-hostable, and busy: last commit to master on 11 September 2026, 21,619 stars, 240 open issues, not archived. The GitHub releases tab is stuck at v2.4.0.1 of August 2017 and tells you nothing — versioning moved to continuous builds years ago. What ships is tag 18086, cut on 12 September 2026; the QuantConnect.Lean.Engine NuGet package at 2.5.18042, published 31 August 2026; and the lean CLI on PyPI at 1.0.229, 28 August 2026.

The cloud is that same engine hosted, with the data mounted, a browser IDE and a deploy button. The engine costs nothing; what the cloud sells is compute, cleaned data and the live-trading plumbing.

Pricing

Paid plans are bundles of nodes sold per seat, and the pricing page opens on annual billing. Month-to-month: Researcher $84, Team $168, Trading Firm $480, Institution $1,272. Nodes are also sold separately — a B2-8 backtest node $14/month, an R1-4 research node $12, live nodes from $24 to $1,000 — so a pack price is a floor, not a ceiling.

Those four figures are the recommended packs rather than the entry price. A Researcher seat on its own is $10/month; the $84 pack is that seat plus one research node (1 CPU, 4 GB), one backtest node (2 CPU, 8 GB), one live node (1 CPU, 0.5 GB), one AI agent node and Bronze support. Seats carry the features, nodes carry the compute, and the two are billed separately, so the plan is assembled rather than chosen.

Data & coverage

US equities, options, index options and futures from AlgoSeek, plus forex, CFDs, crypto and international futures, tick to daily, with corporate fundamentals in every tier. Universe selection is written in code, not clicked in a screener.

Local downloads are billed separately, and that is where budgets break. On a Researcher seat the US Equity Security Master is $600/year (it rises to $1,800/year at Institution), AlgoSeek's US equity minute history $980/month and its tick history $1,400/month, current coarse-universe files $240/year, Benzinga news $120/month, Quiver's congress and insider feeds $5/month each.

Integrations

Python or C#. An official MCP server — now shipped inside the VS Code Local Platform extension, with the standalone repo marked deprecated — lets an LLM create projects, run backtests and deploy live algorithms through the API. Live algorithms notify over Telegram, email, webhook and SMS, the last billed in QCC tokens at 1 USD per 100 (1 QCC domestic, 10 international per message).

Limitations

• The free tier is a demo of the cloud, not a free platform: no live trading — the live-node limit is literally zero — no second or tick data, no API, no CLI. What it does allow is one backtest node, one research node, 200 projects, 500 MB of workspace, 32 KB per file, 25 data-file downloads per backtest and 10,000 orders and insights in a single backtest, against 10 million on a Researcher seat. A universe strategy reaches that last one quickly.
• LEAN's licence is free; its data is not, and self-hosting means sourcing all of it yourself.
• No screener, charting or portfolio UI. Everything is code.
• The abstractions — algorithm framework, universe selection, consolidators — are a real learning curve, and a strategy written against them ports nowhere else.

Alternatives

Backtrader and Zipline-reloaded for a plain Python library, NautilusTrader for a faster event-driven core, QuantRocket for the hosted-with-your-own-data shape.