# External Pricing Source Configuration¶

Updated as of v0.36.0

By default, Hummingbot uses the order book you're trading in to generate the mid price (between the top bid and the top ask) as a starting price to calculate maker order prices.

With this feature, users have the option to choose a different price reference for your orders such as last trade price, last own trade price, best bid price, best ask price and inventory cost. Users can also use a different order book such as an external exchange supported by Hummingbot or a custom API.

## How it works¶

In a situation where the calculation of maker order prices from external sources would result in the order matching any existing orders on the order book, such order will be ignored unless take_if_crossed parameter is enabled.

## Price source: current market¶

By default, price_source is set to current_market.

 1 2 3 4  exchange: binance market: BTC-USDC bid_spread: 1 ask_spread: 1 
 1 2 3 4 5 6  price_source: current_market price_type: mid_price price_source_exchange: None price_source_market: None take_if_crossed: None price_source_custom_api: None 

## Price source: external market¶

Users can also use an external market from another exchange supported by Hummingbot as the price reference when creating orders.

In the example below, we're trading on BTC-USDC pair in Binance while using the mid price of BTC-USDT market from Crypto.com exchange.

 1 2 3 4  exchange: binance market: BTC-USDC bid_spread: 1 ask_spread: 1 
 1 2 3 4 5 6  price_source: external_market price_type: mid_price price_source_exchange: crypto_com price_source_market: BTC-USDT take_if_crossed: True price_source_custom_api: None 

Run config price_type command to change the price reference to last_price, last_own_trade_price, best_bid, and best_ask. The parameter take_if_crossed is optional as this only allows users to take existing orders from the order book if there is an existing match.

Note

Currently, the external price source cannot be the same as the maker exchange (i.e. if the bot is trading on Binance, the price_source_exchange cannot be Binance)

## Price source: custom API¶

Custom API is mostly used by advanced users or developers for using a different price reference. Take note that price_source should be set to custom_api with the API URL indicated in price_source_custom_api.

 1 2 3 4 5 6  price_source: custom_api price_type: mid_price price_source_exchange: None price_source_market: None take_if_crossed: None price_source_custom_api: https://www.your-custom-api-url.com/ 

Custom API Output Required Parameters

The API GET request should return a decimal number corresponding to a market price for the asset pair you are trading on.

Sample API Output:

 1 207.8 

## When to use an external price source¶

External price source is valuable when your bot is market making for a relatively illiquid trading pair, but a more liquid pair with the same underlying exposure is available on a different exchange.

Suppose we are market making for the ETH-USDT trading pair. The exchange we are trading on, denoted as Exchange A, has the top bid order at $198 and the top ask order at$202, so the mid price is $200. Let's suppose there is Exchange B with an ETH-USD trading pair. That pair has a top bid order at$200 while the top ask order is $202, so the mid price is$201. These discrepancies often happens between different exchanges as market conditions change. Some exchanges may react more slowly or quickly to market changes due to differences in the trading pair, liquidity, geography.

If you believe that ETH-USD on Exchange B is more liquid and responds more quickly to market information than ETH-USDT on Exchange A, you may want to market make on Exchange A but use ETH-USD on Exchange B as the price source. This helps you position your orders based on where the market might go in the future.

## Taking crossed orders¶

When using an external price source, an order may result in a crossed market. This means the order on the current exchange is placed with a price that matches an existing order in the book. Enabling take_if_crossed parameter allows the strategy to fill the matching maker order.

In certain cases, this behavior may be desirable even if the fee is higher because of the likely future price mitigation. This feature is only available when an external price source is used. When enabled, Hummingbot uses LIMIT order instead of LIMIT_MAKER order type.

## price_source¶

Determines which market to be used as price reference when creating orders.

** Prompt: **

 1 2 Which price source to use? (current_market/external_market/custom_api) >>> current_market 

## price_type¶

Price type to be used as price reference when creating orders.

** Prompt: **

 1 2 Which price type to use? (mid_price/last_price/last_own_trade_price/best_bid/best_ask/inventory_cost) >>> mid_price 

mid_price

Hummingbot uses the mid price of the market's order book in the current exchange as reference e.g. if your bid/ask spread is set to 1, your orders will be created 1% away from the mid price. Mid price - is calculated (market best ask + market best bid) / 2.

 1 2  price_source: current_market price_type: mid_price 

last_price

Last price is the most recent price that the asset has been traded.

 1 2  price_source: current_market price_type: last_price 

last_own_trade_price

The bot uses the last own trade price as a price reference when creating orders.

 1 2  price_source: current_market price_type: last_own_trade_price 

best_bid

When price_type is set to best_bid, the price will be based on the best bid in the order book.

 1 2  price_source: current_market price_type: best_bid 

best_ask

When price_type is set to best_ask, the price will be based on the best ask in the order book.

 1 2  price_source: current_market price_type: best_ask 

inventory_cost

The bot will calculate the average cost of your inventory every time a buy order is filled, and all sell orders will be created at inventory_cost + ask_spread. When using inventory_cost, you would need to set inventory price before you start your Hummingbot using this command config inventory_price

 1 2  price_source: current_market price_type: inventory_cost 

## price_source_exchange¶

Name of exchange to be used for external pricing source.

** Prompt: **

 1 2 Enter external price source exchange name >>> 

## price_source_market¶

The trading pair for the price source exchange.

** Prompt: **

 1 2 Enter the token pair on [price_source_exchange] >>> 

## take_if_crossed¶

Take order if they cross orderbook when external price source is enabled.

** Prompt: **

 1 2 Do you want to take the best order if orders cross the orderbook? (Yes/No) >>> Yes 

## price_source_custom_api¶

An external API that returns price.

** Prompt: **

 1 2 Enter pricing API URL >>>