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CoinAPI Indexes API Quickstart

This quickstart guide will help you get started with the CoinAPI Indexes API.

Prerequisites​

To follow this tutorial, you'll need:

  • A CoinAPI key (sign up at CoinAPI if you don't have one)
  • curl installed on your system

1. Retrieve Last Index Value​

Let's start by fetching the last value for the BTC/USD index using the REST API.

Real-World Scenario: Valuing Cryptocurrency Assets for Financial Reporting

Imagine you're conducting a financial audit for a company that holds cryptocurrency assets. You need to determine the current USD value of their Bitcoin(BTC) holdings for an accurate financial statement.

curl -H "X-CoinAPI-Key: YOUR_API_KEY" \
     "https://rest.coinapi.io/v1/indexes/IDX_REFRATE_PRIMKT_BTC_USD/latest"

Replace YOUR_API_KEY with your actual CoinAPI key.

This request will return the latest value of the BTC/USD index. The response will look similar to this:

{
  "index_id": "IDX_REFRATE_PRIMKT_BTC_USD",
  "sequence": 2323346,
  "time_coinapi": "2023-06-01T12:00:00.0000000Z",
  "value": 27500.12
}

2. Fetch Index Timeseries​

Now, let's retrieve the timeseries data for the ETH/USD index for the last 24 hours with 1-hour intervals.

Real-World Scenario: Auditing Cryptocurrency Transactions

Imagine you're an auditor reviewing a company's cryptocurrency transactions. The company claims to have executed a significant ETH/USD trade at a specific time yesterday, stating they achieved an optimal price. To verify this claim and ensure the transaction's fairness, you need to analyze the ETH/USD price movements over the past 24 hours.

curl -H "X-CoinAPI-Key: YOUR_API_KEY" \
     "https://rest.coinapi.io/v1/indexes/IDX_REFRATE_PRIMKT_ETH_USD/timeseries?period_id=1HRS&time_start=2023-06-01T00:00:00&time_end=2023-06-02T00:00:00&limit=24"

Replace YOUR_API_KEY with your actual CoinAPI key, and adjust the time_start and time_end parameters to reflect the current date.

The response will contain an array of index values for each hour:

[
  {
    "index_id": "IDX_REFRATE_PRIMKT_ETH_USD",
    "sequence": 2323300,
    "time_period_start": "2023-06-01T00:00:00.0000000Z",
    "time_period_end": "2023-06-01T01:00:00.0000000Z",
    "time_open": "2023-06-01T00:00:00.0000000Z",
    "time_close": "2023-06-01T00:59:59.9999999Z",
    "value_open": 1850.25,
    "value_high": 1855.50,
    "value_low": 1848.75,
    "value_close": 1852.30
  },
  // ... more entries for each hour
]

3. Subscribe to Real-time Index Updates​

Finally, let's use WebSocket to subscribe to real-time updates for both BTC/USD and ETH/USD indexes.

Real-World Scenario: Market Monitoring

Imagine you're a cryptocurrency trader seeking a comprehensive view of BTC and ETH prices across the majority of the market. You want to monitor real-time market trends to make informed trading decisions.

First, establish a WebSocket connection:

curl -i -N -H "Sec-WebSocket-Version: 13" \
     -H "Sec-WebSocket-Key: SGVsbG8sIHdvcmxkIQ==" \
     -H "Connection: Upgrade" \
     -H "Upgrade: websocket" \
     -H "Host: ws-api.indexes.coinapi.io" \
     -H "Origin: http://localhost" \
     https://ws-api.indexes.coinapi.io

After the connection is established, send a subscription message:

{
  "type": "hello",
  "heartbeat": false,
  "subscribe_filter_index_id": [
    "IDX_REFRATE_PRIMKT_BTC_USD",
    "IDX_REFRATE_PRIMKT_ETH_USD"
  ]
}

Replace YOUR_API_KEY with your actual CoinAPI key.

You'll start receiving real-time index updates for both BTC/USD and ETH/USD. Each update will look similar to this:

{
  "type": "index",
  "index_id": "IDX_REFRATE_PRIMKT_BTC_USD",
  "sequence": 2323347,
  "time_coinapi": "2023-06-01T12:01:00.0000000Z",
  "value": 27505.50
}

Recap​

This quickstart guide demonstrates how to use the CoinAPI Indexes API to retrieve the last index value, fetch timeseries data, and subscribe to real-time index updates. You can build upon these examples to create more complex applications and analyses using the CoinAPI Indexes data.