Betfair

Founded in 2000, Betfair operates the world’s largest online betting exchange, with its headquarters in London and satellite offices across the globe.

PoseiTrader provides an adapter for integrating with the Betfair REST API and Exchange Streaming API.

Installation

Install PoseiTrader with Betfair support via pip:

pip install --upgrade "posei_trader[betfair]"

To build from source with Betfair extras:

uv sync --all-extras

Examples

You can find live example scripts here.

Betfair documentation

For API details and troubleshooting, see the official Betfair Developer Documentation.

Application Keys

Betfair requires an Application Key to authenticate API requests. After registering and funding your account, obtain your key using the API-NG Developer AppKeys Tool.

info

See also the Betfair Getting Started - Application Keys guide.

API credentials

Supply your Betfair credentials via environment variables or client configuration:

export BETFAIR_USERNAME=<your_username>
export BETFAIR_PASSWORD=<your_password>
export BETFAIR_APP_KEY=<your_app_key>
export BETFAIR_CERTS_DIR=<path_to_certificate_dir>

tip

We recommend using environment variables to manage your credentials.

Overview

The Betfair adapter provides three primary components:

• BetfairInstrumentProvider: loads Betfair markets and converts them into Posei instruments.
• BetfairDataClient: streams real-time market data from the Exchange Streaming API.
• BetfairExecutionClient: submits orders (bets) and tracks execution status via the REST API.

Capability Matrix

Betfair operates as a betting exchange with unique characteristics compared to traditional financial exchanges:

Order Types

Order Type	Betfair	Notes
MARKET	-	Not applicable to betting exchange.
LIMIT	✓	Orders placed at specific odds.
STOP_MARKET	-	Not supported.
STOP_LIMIT	-	Not supported.
MARKET_IF_TOUCHED	-	Not supported.
LIMIT_IF_TOUCHED	-	Not supported.
TRAILING_STOP_MARKET	-	Not supported.

Execution Instructions

Instruction	Betfair	Notes
post_only	-	Not applicable to betting exchange.
reduce_only	-	Not applicable to betting exchange.

Time-in-Force Options

Time-in-Force	Betfair	Notes
GTC	-	Betting exchange uses different model.
GTD	-	Betting exchange uses different model.
FOK	-	Betting exchange uses different model.
IOC	-	Betting exchange uses different model.

Advanced order features

Feature	Betfair	Notes
Order Modification	✓	Limited to non-exposure changing fields.
Bracket/OCO Orders	-	Not supported.
Iceberg Orders	-	Not supported.

Configuration options

The following execution client configuration options affect order behavior:

Option	Default	Description
calculate_account_state	True	If True, calculates account state from events.
request_account_state_secs	300	Interval for account state checks in seconds (0 disables).
reconcile_market_ids_only	False	If True, only reconciles orders for configured market IDs.
ignore_external_orders	False	If True, silently ignores orders not found in cache.

Configuration

Here is a minimal example showing how to configure a live TradingNode with Betfair clients:

from posei_trader.adapters.betfair import BETFAIR
from posei_trader.adapters.betfair import BetfairLiveDataClientFactory
from posei_trader.adapters.betfair import BetfairLiveExecClientFactory
from posei_trader.config import TradingNodeConfig
from posei_trader.live.node import TradingNode

# Configure Betfair data and execution clients (using AUD account currency)
config = TradingNodeConfig(
    data_clients={BETFAIR: {"account_currency": "AUD"}},
    exec_clients={BETFAIR: {"account_currency": "AUD"}},
)

# Build the TradingNode with Betfair adapter factories
node = TradingNode(config)
node.add_data_client_factory(BETFAIR, BetfairLiveDataClientFactory)
node.add_exec_client_factory(BETFAIR, BetfairLiveExecClientFactory)
node.build()