user75781: I am using CryptoCompare's API and it gives me volume data, but I am wondering where I can get market cap / circulating supply data. Do any reliable API's provide this?

user60707: As Adam answered, the Coinmarketcap.com API has a ton of data that's aggregated from a ton of sources. Also, it's been around for a while and the API is accessible 24/7, so it's definitely one of the more reliable services. I heard they even filter out sources with outlier data, such as price or volume spikes from artificial pumping or commission-free trades, which makes the data that much more reliable (IMO).
The following URL will return JSON with high-level stats for every coin tracked by the API:
https://api.coinmarketcap.com/v1/ticker/
A sample response is as follows:
[{
        "id": "bitcoin", 
        "name": "Bitcoin", 
        "symbol": "BTC", 
        "rank": "1", 
        "price_usd": "10077.0", 
        "price_btc": "1.0", 
        "24h_volume_usd": "9717610000.0", 
        "market_cap_usd": "169661279499", 
        "available_supply": "16836487.0", 
        "total_supply": "16836487.0", 
        "max_supply": "21000000.0", 
        "percent_change_1h": "1.34", 
        "percent_change_24h": "-9.2", 
        "percent_change_7d": "-7.58", 
        "last_updated": "1517379267"
    }, 
    {
        "id": "ethereum", 
        "name": "Ethereum", 
        "symbol": "ETH", 
        "rank": "2", 
        "price_usd": "1077.71", 
        "price_btc": "0.107872", 
        "24h_volume_usd": "4432010000.0", 
        "market_cap_usd": "104880306525", 
        "available_supply": "97317745.0", 
        "total_supply": "97317745.0", 
        "max_supply": null, 
        "percent_change_1h": "1.06", 
        "percent_change_24h": "-7.55", 
        "percent_change_7d": "8.78", 
        "last_updated": "1517379253"
 }]

Some of the properties you may be interested in are as follows:

"market_cap_usd": Market cap in US dollars.
"available_supply": Circulating supply.
"total_supply": Total supply issued/mined.
"max_supply": Total supply the platform/protocol currently allows for.


user63569: Checkout coinmarketcap. they've all API you may need for cryptocurrencies 

75781: <p>I am using CryptoCompare's API and it gives me volume data, but I am wondering where I can get market cap / circulating supply data. Do any reliable API's provide this?</p>
 60707: <p>As Adam answered, the <a href="https://coinmarketcap.com/api/" rel="nofollow noreferrer">Coinmarketcap.com API</a> has a ton of data that's aggregated from a ton of sources. Also, it's been around for a while and the API is accessible 24/7, so it's definitely one of the more reliable services. I heard they even filter out sources with outlier data, such as price or volume spikes from artificial pumping or commission-free trades, which makes the data that much more reliable (IMO).</p>

<p>The following URL will return JSON with high-level stats for every coin tracked by the API:</p>

<p><a href="https://api.coinmarketcap.com/v1/ticker/" rel="nofollow noreferrer">https://api.coinmarketcap.com/v1/ticker/</a></p>

<p>A sample response is as follows:</p>

<pre><code>[{
        "id": "bitcoin", 
        "name": "Bitcoin", 
        "symbol": "BTC", 
        "rank": "1", 
        "price_usd": "10077.0", 
        "price_btc": "1.0", 
        "24h_volume_usd": "9717610000.0", 
        "market_cap_usd": "169661279499", 
        "available_supply": "16836487.0", 
        "total_supply": "16836487.0", 
        "max_supply": "21000000.0", 
        "percent_change_1h": "1.34", 
        "percent_change_24h": "-9.2", 
        "percent_change_7d": "-7.58", 
        "last_updated": "1517379267"
    }, 
    {
        "id": "ethereum", 
        "name": "Ethereum", 
        "symbol": "ETH", 
        "rank": "2", 
        "price_usd": "1077.71", 
        "price_btc": "0.107872", 
        "24h_volume_usd": "4432010000.0", 
        "market_cap_usd": "104880306525", 
        "available_supply": "97317745.0", 
        "total_supply": "97317745.0", 
        "max_supply": null, 
        "percent_change_1h": "1.06", 
        "percent_change_24h": "-7.55", 
        "percent_change_7d": "8.78", 
        "last_updated": "1517379253"
 }]
</code></pre>

<p>Some of the properties you may be interested in are as follows:</p>

<ul>
<li>"market_cap_usd": Market cap in US dollars.</li>
<li>"available_supply": Circulating supply.</li>
<li>"total_supply": Total supply issued/mined.</li>
<li>"max_supply": Total supply the platform/protocol currently allows for.</li>
</ul>
 63569: <p>Checkout <a href="https://coinmarketcap.com/api/" rel="nofollow noreferrer">coinmarketcap</a>. they've all API you may need for cryptocurrencies </p>
