Poloniex API Documentation: Everything You Need to Know

Poloniex, a global cryptocurrency exchange, provides an API (Application Programming Interface) that allows developers to interact with its platform programmatically. This documentation will guide you through the different functionalities, features, and use cases of the Poloniex API. Whether you are an advanced trader looking to automate your strategies or a developer integrating Poloniex into an external system, understanding the API is crucial for seamless interaction.

Introduction to Poloniex API

Poloniex offers a comprehensive API for both private and public functions. The API is divided into three categories:

1. Public API: Offers data that does not require authentication, such as ticker prices, trading pairs, and market depth.
2. Private API: Requires authentication (via API keys) and provides access to account-specific data like balances, open orders, and trade history.
3. WebSocket API: Designed for real-time updates on market data and events.

This article dives deep into each API type, detailing their requests, responses, and best practices for implementation.

The Basics of Using Poloniex API

Authentication

To access the private API, you’ll need an API key and a secret provided by Poloniex. Authentication is conducted via HMAC-SHA512 signatures, which ensure the security of requests. Each API request must be signed with a timestamp and passed in the request header.

Key steps for setting up authentication:

• Generate an API key in the Poloniex user interface.
• Pass the API key, timestamp, and signature in the request header.
• Ensure that your server's clock is synchronized with world time servers to avoid authentication errors.

Rate Limits

Poloniex enforces rate limits to ensure fair usage of their API. The rate limit is currently 6 calls per second for the REST API. Exceeding this limit will result in HTTP 429 responses, signaling that too many requests have been sent in a short period.

Request Type	Max Calls/Second
Public API	6
Private API	6
WebSocket	No Limit

Key Features of Poloniex API

1. Public API

The public API is essential for accessing general market data. Some common endpoints include:

• /returnTicker: Provides current price data for all trading pairs.
• /return24hVolume: Shows the 24-hour trading volume for all coins.
• /returnOrderBook: Returns the order book for a specified market.
• /returnTradeHistory: Fetches the trade history for a market.

Example request for fetching ticker data:

bash
curl https://poloniex.com/public?command=returnTicker

The response will include details like:

json
{
   "BTC_ETH": {
      "last": "0.032315", 
      "lowestAsk": "0.0324", 
      "highestBid": "0.0322", 
      "percentChange": "-0.0234",
      "baseVolume": "12.43891", 
      "quoteVolume": "383.034"
   }
}

This data can be used to track market trends, set up custom alerts, or integrate price feeds into a broader platform.

2. Private API

The private API allows users to access and manage their account data. Key endpoints include:

• /returnBalances: Returns the current balances for all assets.
• /returnCompleteBalances: Shows available and unavailable balances for each currency.
• /returnOpenOrders: Lists the open orders for a specified trading pair.
• /returnTradeHistory: Retrieves the trade history for a specific market or all markets.

Example request for fetching account balances:

bash
curl https://poloniex.com/tradingApi \
-d command=returnBalances \
-d nonce=123456 \
-H 'Key: YOUR_API_KEY' \
-H 'Sign: YOUR_SIGNATURE'

The response includes:

json
{
   "BTC": "0.0001", 
   "ETH": "2.1345", 
   "XRP": "0"
}

3. WebSocket API

Poloniex's WebSocket API is the preferred choice for users needing real-time market updates. The WebSocket API provides:

• Order book updates: Push notifications for changes in the order book.
• Trade execution data: Information on completed trades.
• Ticker updates: Instant updates on market prices.

A WebSocket client connects to the server by sending:

bash
wss://api2.poloniex.com

The server responds with real-time messages, such as:

json
[
  121,
  null,
  [ [ "i", {"symbol": "BTC_ETH", "lastTradePrice": "0.032315"} ] ]
]

Use Cases for Poloniex API

Automating Trades

For algorithmic traders, automating strategies using the Poloniex API is highly beneficial. By integrating API calls into trading bots, traders can execute orders based on predefined conditions, such as price thresholds or technical indicators. A typical use case might involve:

• Fetching market data at regular intervals.
• Placing buy or sell orders when certain market conditions are met.
• Tracking open orders and trade history to adjust strategies in real time.

Portfolio Management

Portfolio management tools use the Poloniex API to track holdings across multiple exchanges. By integrating the /returnBalances endpoint, users can view their asset distribution, calculate total portfolio value, and monitor asset performance over time.

Common Errors and Troubleshooting

1. Invalid API Key

If the API key is incorrect or has not been set up properly, the request will return an error:

json
{
  "error": "Invalid API key/secret pair"
}

Ensure that the key and secret are correct, and that the API has the necessary permissions for the requested action.

2. Nonce Too Small

The Poloniex API uses a nonce (a unique number that can only be used once) to prevent replay attacks. Each request must have a nonce larger than the previous one. If not, you'll receive the error:

json
{
  "error": "Nonce must be greater than 123456"
}

Ensure that your application generates nonces properly by using a timestamp or incrementing counter.

3. Rate Limit Exceeded

If you exceed the API's rate limit, you'll get an HTTP 429 response. To avoid this, reduce the frequency of requests or implement a rate-limiting mechanism in your application.

Conclusion

The Poloniex API is a powerful tool for developers and traders alike. Whether you're building a trading bot, tracking real-time market data, or managing a cryptocurrency portfolio, the API offers robust capabilities. By understanding its features and limitations, you can unlock its full potential and enhance your experience on the Poloniex platform.