Overview

Introduction

NautilusTrader is an open‑source, production‑grade, Rust‑native engine for multi‑asset, multi‑venue trading systems.

The system spans research, deterministic simulation, and live execution within a single event‑driven architecture, with Python serving as the control plane for strategy logic, configuration, and orchestration.

This separation provides the performance and safety of a compiled trading engine with the flexibility of Python for system composition and strategy development. Trading systems can also be written entirely in Rust for mission‑critical workloads.

The same execution semantics and deterministic time model operate in both research and live systems. Strategies deploy from research to production with no code changes, providing research‑to‑live parity and reducing the divergence that typically introduces deployment risk.

NautilusTrader is asset‑class‑agnostic. Any venue with a REST API or WebSocket feed can be integrated through modular adapters. Integrations span centralized and decentralized crypto exchanges (CEX and DEX), foreign exchange (FX), equities, futures, options, and betting exchanges.

Features

• Fast: Rust core with asynchronous networking using tokio.
• Reliable: Rust provides type safety and thread safety, with optional state persistence backed by Redis or PostgreSQL.
• Portable: Runs on Linux, macOS, and Windows. Deploy using Docker.
• Flexible: Modular adapters integrate any REST API or WebSocket feed.
• Advanced orders: Time‑in‑force options include IOC, FOK, GTC, GTD, DAY, AT_THE_OPEN, and AT_THE_CLOSE. The domain model also supports conditional triggers, post-only, reduce-only, iceberg, and OCO, OUO, and OTO contingency orders. Venue support varies by adapter.
• Customizable: User‑defined components, or assemble entire systems from scratch using the cache and message bus.
• Backtesting: Run multiple venues, instruments, and strategies simultaneously using historical quotes, trades, bars, order books, and custom data with nanosecond resolution.
• Live: Identical strategy implementations between research and live deployment.
• Multi‑venue: Run market‑making and cross‑venue strategies across multiple venues simultaneously.
• AI training: High‑throughput simulation supports workloads such as training AI trading agents with reinforcement learning (RL) or evolutionary strategies (ES).

Why NautilusTrader?

Trading strategy research typically happens in Python using vectorized approaches, while production trading systems are built separately using event‑driven architectures in compiled languages.

NautilusTrader removes this separation.

A Rust‑native core provides a deterministic event‑driven runtime for both research and live execution, while Python serves as the control plane. The same architecture, execution semantics, and time model operate across both environments, allowing strategies to move from research to production without reimplementation.

Python bindings for the Rust‑native v2 runtime are provided via PyO3. The legacy Cython v1 core remains supported during the v2 release‑candidate phase. Installing an official prebuilt Python wheel does not require a Rust toolchain.

Use cases

NautilusTrader supports three main use cases:

• Backtest trading systems on historical data (backtest).
• Simulate trading systems with real‑time data and virtual execution (sandbox).
• Deploy trading systems live on real or paper accounts (live).

NautilusTrader provides backtest and live node implementations for both Python and Rust. The sandbox adapter supplies simulated execution for a sandbox environment.

Distributed

The platform integrates into larger distributed systems. The external message bus supports JSON and MessagePack payloads, plus Cap'n Proto and Simple Binary Encoding (SBE) for schema‑covered market data. Apache Arrow and Parquet provide columnar interchange and persistence through the data catalog. Format support varies by payload type.

Common core

The common system core is used by all node environment contexts: backtest, sandbox, and live. User‑defined actors, strategies, and execution algorithms use the same lifecycle across these contexts.

Backtesting

Feed data to a BacktestEngine either directly or through a higher‑level BacktestNode and ParquetDataCatalog, then run the data through the system with nanosecond resolution. See Backtesting for the APIs and execution model.

Live trading

A LiveNode ingests data and events from multiple data and execution clients, supporting demo, paper, and real accounts. The Rust‑native node, including its PyO3 interface, runs the kernel event loop on the calling thread, while asynchronous I/O and background tasks use a shared multi‑threaded Tokio runtime. The legacy Python TradingNode coordinates asynchronous clients through an asyncio event loop and can use uvloop on Linux and macOS. See Live trading for the node lifecycle and risk considerations, and Execution reconciliation for state recovery.

Domain model

The trading domain model includes value types such as Price and Quantity, plus orders and positions that aggregate events to determine state.

Timestamps

NautilusTrader represents system timestamps as UNIX nanoseconds. Its standard ISO 8601 (RFC 3339) formatter uses UTC and preserves all nine fractional digits. A millisecond formatter preserves three fractional digits for selected displays, such as good‑till‑date (GTD) expiry times.

A timestamp string consists of:

• Full date component always present: YYYY-MM-DD.
• T separator between date and time components.
• Nine fractional digits for nanosecond output, or three for millisecond output.
• UTC timezone designated by the Z suffix.

Example: 2024-01-05T15:30:45.123456789Z

For the complete specification, refer to RFC 3339: Date and Time on the Internet.

UUIDs

The UUID4 value type provides random Universally Unique Identifier (UUID) version 4 values for events, commands, reports, and other internal messages. It uses the uuid crate to validate version and variant bits when parsing strings.

A valid UUID v4 under RFC 9562 consists of:

• 32 hexadecimal digits displayed in 5 groups.
• Groups separated by hyphens: 8-4-4-4-12 format.
• Version 4 designation (indicated by the third group starting with "4").
• IETF variant designation (indicated by the fourth group starting with "8", "9", "a", or "b").

Example: 2d89666b-1a1e-4a75-b193-4eb3b454c757

For the complete specification, see RFC 9562: Universally Unique Identifiers (UUIDs).

Data types

NautilusTrader defines the following built‑in market and reference data types. Availability for historical requests and live subscriptions depends on the provider and adapter. See Data for their fields and behavior.

• OrderBookDelta (single order book change)
• OrderBookDeltas (container type)
• OrderBookDepth10 (fixed depth of 10 levels per side)
• QuoteTick
• TradeTick
• Bar
• MarkPriceUpdate
• IndexPriceUpdate
• FundingRateUpdate
• OptionGreeks
• Instrument
• InstrumentStatus
• InstrumentClose

Use custom data for application‑specific types.

The following PriceType options select granular data for internal bar aggregation:

• BID
• ASK
• MID
• LAST

BID, ASK, and MID use QuoteTick data, while LAST uses TradeTick data. Composite bar types aggregate smaller bars instead.

Bar aggregations

The following BarAggregation methods are available:

• MILLISECOND
• SECOND
• MINUTE
• HOUR
• DAY
• WEEK
• MONTH
• YEAR
• TICK
• VOLUME
• VALUE (also known as dollar bars)
• RENKO (price‑based bricks)
• TICK_IMBALANCE
• TICK_RUNS
• VOLUME_IMBALANCE
• VOLUME_RUNS
• VALUE_IMBALANCE
• VALUE_RUNS

All listed aggregations are implemented for internal aggregation. Information‑driven aggregations require TradeTick data.

A BarSpecification combines a price type, aggregation method, and positive step size. Fixed‑subunit time bars have divisibility limits; see Bar types for the validation rules. Internal aggregation can run during live trading when the required input data is available.

Account types

The accounting engine supports the following configurations in both live and backtest environments:

• Cash single‑currency (base currency)
• Cash multi‑currency
• Margin single‑currency (base currency)
• Margin multi‑currency
• Betting single‑currency

Order types

The order model supports the following types, subject to venue adapter support:

• MARKET
• LIMIT
• STOP_MARKET
• STOP_LIMIT
• MARKET_TO_LIMIT
• MARKET_IF_TOUCHED
• LIMIT_IF_TOUCHED
• TRAILING_STOP_MARKET
• TRAILING_STOP_LIMIT

Value types

The following fixed‑point value types are backed by either 128‑bit or 64‑bit raw integers, depending on the precision mode used during compilation.

• Price
• Quantity
• Money

Official Python wheels use high‑precision mode on Linux and macOS, and standard‑precision mode on Windows. Pure Rust builds default to standard precision unless the high-precision feature is enabled.

High-precision mode (128-bit)

When the high-precision feature flag is enabled, values use the specification:

Standard-precision mode (64-bit)

When the high-precision feature flag is disabled, values use the specification: