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Coin Market Cap

Coin market cap provides quality information about cryptocurrency and blockchain technologies. As part of their products they have a blog, portfolio management, and API, etc. The coin market cap API provides a RESTful JSON endpoint with the latest information about the prices, airdrops, chain supported, and project information.

Credentials

For CMC, we will need just the API key, and to get this API key:

  1. Navigate to https://coinmarketcap.com/api/
  2. Create an account ( in case we do not have one already)
  3. Get an API key (you will find the link asking you if you want to get the API key)
  4. You will be redirected to https://pro.coinmarketcap.com/account

Coin Market Cap API Dashboard

Remember that CMC provides a different package to work with their API, some endpoints are just for pro members, but you can get along with the free package.

Authentication

You can provide the API key in two ways:

  1. Via headers ( X-CMC_PRO_API_KEY )
  2. As a parameter in the query string ( string parameter CMC_PRO_API_KEY)

The recommended method is via headers. Honestly, it is the easiest way. Here is the example provided by CMC:

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from requests import Request, Session
from requests.exceptions import ConnectionError, Timeout, TooManyRedirects
import json

url = 'https://sandbox-api.coinmarketcap.com/v1/cryptocurrency/listings/latest'
parameters = {
  'start':'1',
  'limit':'5000',
  'convert':'USD'
}
headers = {
  'Accepts': 'application/json',
  'X-CMC_PRO_API_KEY': 'YOUR API KEY GOES HERE',
}

session = Session()
session.headers.update(headers)

try:
  response = session.get(url, params=parameters)
  data = json.loads(response.text)
  print(data)
except (ConnectionError, Timeout, TooManyRedirects) as e:
  print(e)

From the code above, please notice:

  1. There is a variable called headers. Here we added the key X-CMC_PRO_API_KEY and the value. This value will be the API key we already generate.
  2. the other step is just an API call using requests

CMC explains it really well in the session API Key Usage Credits

Endpoints Overview

Here CMC shows the skill by explaining in detail and few words how the API was designed, here is the main point:

  1. There are 8 endpoints each one will provide some type of information.
  2. Additional to the endpoint will be some patterns. These patterns will match the type of information provided. For example, if you want the latest market price, the pattern needs it will include /latest, now if what you want is the historical data the pattern will include /historical.

This table is the same in the documentation.

Endpoints

Endpoint Category Description
/cryptocurrency/* Endpoints that return data about the cryptocurrencies include price, ranking, etc.
/exchange/* Endpoints that return data about the cryptocurrency exchanges
/global-metrics/* Endpoints that return aggregate market data such as global market cap and BTC dominance.
/tools/* Useful utilities such as cryptocurrency and fiat price conversions.
/blockchain/* Endpoints that return block explorer-related data for blockchains.
/fiat/* Endpoints that return data around fiats currencies including mapping to CMC IDs.
/partners/* Endpoints for convenient access to 3rd party crypto data.
/key/* API key administration endpoints to review and manage your usage.

Here are a couple of notes:

  1. The endpoint I use the most is /cryptocurrency/* it provides more than enough data.
  2. The Endpoint /tools/* useful and convenient, if combined with /cryptocurrency/* will give you all the information you need.
  3. CMC IDs is a mapping system by CMC for the different currencies and projects, for example, BTC CMC ID will be 1.

Patterns

End path End path tab Description
*/latest latest market data The latest market quote average from the exchanges
*/historical historical market data OHLCV data or data for charting libraries
*/info Metadata Metadata cryptocurrency exchange URLs or logos
*/map ID map Utility endpoint to get the map for resources to CMC IDs

Both endpoints cryptocurrency and exchange will provide two ways to access the data, the first one as listing */listing/* which can be filtered and sorted. Second, as ID-based resources with */quotes/* and */market-pairs/*.

Standards and Conventions

Each HTTP request must contain a header with the following information:

  • Accept: application/json
  • Accept-Encoding: deflate,gzip

Endpoint Response and Payload Format

  1. The information returned will be under the key data if the call is successful.

  2. status key is almost always added to successful and not successful calls, and it will contain:

    1. timestamp when the call was done.
    2. credit_count the number of credits used.
    3. elapsed time that took to process the request.
    4. if and error is encounter error_code and error_message

Bellow the link to the Error and Rate limit page:

Account

but here a quick summary:

HTTP Status code Description
400 Bad request
401 Unauthorized
402 Payment Required
403 Forbidden
429 To Many Request
500 Internal Service Error

Date and Time Format

The timestamp follows the format ISO-8601 (2022-04-04T01:40:40Z) or Unix time (1528249600).

Best Practice

The documentation provides a series of tips and recommendations, This will make it easier to work with the API. ( also show the dedication of the CMC team)

  1. Use CMC ID instead of the Cryptocurrency symbol.
  2. Use the right Endpoint for the job. For general consultation use cryptocurrency/listing/latest. For a more selective consultation cryptocurrency/quotes/latest
  3. Implement a caching strategy to avoid repetitive calls.

A general description of the Endpoint

The documentation provides more detailed information about each endpoint. Here I present just an overview.

cryptocurrency

It has 17 endpoints

Some Endpoints are not available for the free tiers

  • Airdrop and Airdrops
  • Listing historical
  • listing new
  • Trending Gainers & Losers
  • Trending Latest
  • Trending Most Visit
  • Market pairs Laters (v2)
  • OHLCV historical
  • OHLCV latest (v2)
  • Price Performance status (v2)
  • Quote historical (v2)

fiat

One Endpoint.

• /v1/fiat/map - CoinMarketCap ID map

exchange

Information about exchanges.

Contain 7 EndPoints.

Some Endpoints are not available for the free tiers:

  • Listing Latest.
  • Market Pairs Latest.
  • Quote Historical.
  • Quote Latest.

global-metrics

Global Aggregated data.

Two Endpoints.

One Endpoint is not available for the Free tier:

  • Quote Historical

tools

Convenient utilities including price conversion.

One EndPoint.

Blockchain

General information about the BlockChain

One Endpoint.

This EndPoint is not supported in the free tier.

key

This Endpoint will provide information about the API usage, like credits remaining.

One Endpoint.

Target domain and Request example.

All requests must be targeted to:

https://pro-api.coinmarketcap.com

however, there is a sandbox domain that we can use for testing

https://sandbox-api.coinmarketcap.com

And here is a request example:

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from requests import Request, Session
from requests.exceptions import ConnectionError, Timeout, TooManyRedirects
import json
import os

url = 'https://sandbox-api.coinmarketcap.com/v1/cryptocurrency/listings/latest'
parameters = {
  'start':'1',
  'limit':'5000',
  'convert':'USD'
}
headers = {
  'Accepts': 'application/json',
  'X-CMC_PRO_API_KEY': os.environ['COIN_API_KEY'],
}

session = Session()
session.headers.update(headers)

try:
  response = session.get(url, params=parameters)
  data = json.loads(response.text)
  print(data)
except (ConnectionError, Timeout, TooManyRedirects) as e:
  print(e)

Response

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{
      "timestamp": "2022-04-24T04:29:28.687Z",
      "data": [
            {
                  "id": 1,
                  "name": "Bitcoin",
                  "symbol": "BTC",
                  "slug": "bitcoin",
                  "num_market_pairs": 9357,
                  "date_added": "2013-04-28T00:00:00.000Z",
                  "tags": [
                        "mineable",
                        "pow",
                        "sha-256",
                        "store-of-value",
                        "state-channel",
                        "coinbase-ventures-portfolio",
                        "three-arrows-capital-portfolio",
                        "polychain-capital-portfolio",
                        "binance-labs-portfolio",
                        "blockchain-capital-portfolio",
                        "boostvc-portfolio",
                        "cms-holdings-portfolio",
                        "dcg-portfolio",
                        "dragonfly-capital-portfolio",
                        "electric-capital-portfolio",
                        "fabric-ventures-portfolio",
                        "framework-ventures-portfolio",
                        "galaxy-digital-portfolio",
                        "huobi-capital-portfolio",
                        "alameda-research-portfolio",
                        "a16z-portfolio",
                        "1confirmation-portfolio",
                        "winklevoss-capital-portfolio",
                        "usv-portfolio",
                        "placeholder-ventures-portfolio",
                        "pantera-capital-portfolio",
                        "multicoin-capital-portfolio",
                        "paradigm-portfolio"
                  ],
                  "max_supply": 21000000,
                  "circulating_supply": 19020456,
                  "total_supply": 19020456,
                  "platform": null,
                  "cmc_rank": 1,
                  "self_reported_circulating_supply": null,
                  "self_reported_market_cap": null,
                  "last_updated": "2022-04-24T04:29:00.000Z",
                  "quote": {
                        "USD": {
                              "price": 39771.52058406209,
                              "volume_24h": 16208164811.782156,
                              "volume_change_24h": -39.0177,
                              "percent_change_1h": 0.05196188,
                              "percent_change_24h": 1.01643893,
                              "percent_change_7d": -1.37701514,
                              "percent_change_30d": -9.62447945,
                              "percent_change_60d": 4.84949453,
                              "percent_change_90d": 12.37243427,
                              "market_cap": 756472457322.2473,
                              "market_cap_dominance": 40.9044,
                              "fully_diluted_market_cap": 835201932265.3,
                              "last_updated": "2022-04-24T04:29:00.000Z"
                        }
                  }
            },
...