FAQ · Reamer Research and Reamer Server: what they are and who they fit

What are the best vectorbt alternatives in 2026?

vectorbt alternatives depend on why you are leaving. For another vectorised library, bt is a free option. For event-driven backtests, look at Backtrader, backtesting.py, NautilusTrader or LEAN. Reamer Research from Reamer Labs is a paid event-driven engine for strategies on bars, with written fill rules and byte-identical runs.

vectorbt tests large grids of parameters by working on whole price histories as arrays. Two things can push people to look elsewhere: their strategy has become hard to express as arrays, or they need order-level detail in fills and costs.

Why people look for vectorbt alternatives

  • Their rules depend on open positions, pending orders or the account, which is awkward as arrays of signals.
  • They want each order filled by written rules, with spread, slippage, swap and margin.
  • They need a route to live trading. vectorbt is not an execution system.
  • They need a licence for business use. vectorbt uses Apache 2.0 with the Commons Clause, and vectorbt PRO's membership needs a separate arrangement for commercial use.

vectorbt alternatives compared

Details below were checked against each project's own pages in November 2026.

ToolStyleBest forLive tradingPrice
vectorbt PROVectorised, more featuresStaying with vectorbt, with more toolsSignals onlyFrom $25 a month or $500 lifetime
btPython, tree of weighted strategiesPortfolio allocation testsNoneFree (MIT)
backtesting.pyPython, event loopOne instrument, a quick startNone built inFree (AGPL-3.0)
BacktraderPython, event-drivenLearning, a first look at an ideaOlder connectorsFree (GPL-3.0)
NautilusTraderRust core, Python strategiesTicks, order books, many venuesYesFree (LGPL-3.0)
LEANC# core, Python or C# strategiesQuantConnect's engine on your machineSelf-runFree (Apache 2.0)
Reamer ResearchCompiled library, event-drivenStrategies on bars with written fill rulesThrough Reamer Server$1,800 per seat per year

Python backtesters

Larger engines

  • NautilusTrader is built for tick and order-book work, and the same code runs live. It takes more setup, and its README warns of breaking changes between releases.
  • LEAN is a full open-source engine with many asset classes. It is a large system to build and run.

A paid engine for strategies on bars

Reamer Research calls your strategy once per time step with its recent bars and current positions, and fills each order under a public execution specification. Runs with a fixed seed are byte-identical. It works on OHLCV bars. Separate backtests can run from your own threads, so a sweep can use every core. Some researchers use both. See How does Reamer Research compare with vectorbt PRO?

How to choose

If you wantLook at
Signal sweeps written as arrays in PythonStay on vectorbt or move to vectorbt PRO
Portfolio weights and rebalancingbt
A small free event-driven toolbacktesting.py or Backtrader
Ticks, order books or ready venue adaptersNautilusTrader
Systematic strategies on bars, with fills you can read and a route to liveReamer Research and Reamer Server

See Who are Reamer Research and Reamer Server for? Reamer Research has a $225 30-day trial; see pricing.

Next questions

How does Reamer Research compare with vectorbt PRO?vectorbt PRO is a vectorised Python library, very fast at testing thousands of parameter combinations of a strategy whose shape is already fixed. Reamer Research is an event-driven engine that steps through time with order-level fill rules from a written specification, for checking whether a strategy survives realistic costs in the first place. Some researchers use both.What are the best backtesting.py alternatives in 2026?backtesting.py is a good small library for testing one strategy on one instrument, so the best alternative depends on what you have outgrown. For several instruments in one strategy, look at Backtrader or bt. For large parameter sweeps, vectorbt. For ticks, order books and live trading, NautilusTrader or LEAN. For strategies on bars with a written fill specification and modelled costs, Reamer Research is a paid engine library from Reamer Labs. If one instrument is enough, backtesting.py is still maintained and may be all you need.What are the best Backtrader alternatives in 2026?Backtrader's last release was in April 2023. backtesting.py is the simplest step for one instrument. bt suits portfolio rebalancing, vectorbt suits parameter sweeps, and NautilusTrader and LEAN cover ticks, more asset classes and live trading. Reamer Research from Reamer Labs is a paid engine library for strategies on bars, and it keeps Backtrader's bar-by-bar shape. In a published benchmark on 500,000 bars, Backtrader took 15.04 s and Reamer Research took 3.38 s from Python.What is a quant research engine, and how is it different from a backtesting script?A research engine is one shared program that does everything around a strategy (loading and aligning data, simulating fills and costs, accounting, metrics, logs and reports) so that each study contains only the strategy itself. A backtesting script does all of that on its own, once per study. The engine is what lets you test, diagnose, sweep, report and move to live with the same rules every time. A script is quicker to start and is the right tool for a single rough idea.How much do Reamer Research and Reamer Server cost?Reamer Research is USD 1,800 per seat per year, and Reamer Server is USD 7,200 per seat per year. Each is paid once for the year and nothing renews automatically. A 30-day trial costs USD 225 for Reamer Research and USD 900 for Reamer Server. A seat is one product on one machine.

Every answer here restates the documents that ship in the kit, which are authoritative. All questions.

Buy a licence30-day trial or annual licence. Key and kit by email on payment.