CoinMarketCap Market API Skill

This skill covers market-wide cryptocurrency data including global metrics, sentiment indicators, market indices, community activity, news content, charting data, and utility endpoints.

Authentication

All requests require the X-CMC_PRO_API_KEY header.

curl -X GET "https://pro-api.coinmarketcap.com/v1/global-metrics/quotes/latest" 
  -H "X-CMC_PRO_API_KEY: your-api-key"

Get your API key at: https://pro.coinmarketcap.com/login

Base URL

https://pro-api.coinmarketcap.com

Common Use Cases

See use-cases.md for goal-based guidance on which endpoint to use:

1. Get current market sentiment (Fear & Greed)
2. Get total crypto market cap
3. Get BTC dominance
4. Track market cap history
5. Track Fear & Greed history
6. Get CMC100 index performance
7. Compare CMC100 vs CMC20
8. Get OHLCV candlestick data for charts
9. Get simple price time series
10. Get community trending tokens
11. Get trending discussion topics
12. Get latest crypto news
13. Convert currency amounts
14. Check API usage and limits
15. Get fiat currency IDs

API Overview

Global Metrics

Endpoint	Description	Reference
GET /v1/global-metrics/quotes/historical	Historical global market metrics	global-metrics.md
GET /v1/global-metrics/quotes/latest	Latest total market cap, BTC dominance	global-metrics.md

Fear and Greed Index

Endpoint	Description	Reference
GET /v3/fear-and-greed/historical	Historical fear/greed values	fear-greed.md
GET /v3/fear-and-greed/latest	Current market sentiment score	fear-greed.md

Market Indices

Endpoint	Description	Reference
GET /v3/index/cmc100-historical	CMC100 index history	indices.md
GET /v3/index/cmc100-latest	CMC100 current value	indices.md
GET /v3/index/cmc20-historical	CMC20 index history	indices.md
GET /v3/index/cmc20-latest	CMC20 current value	indices.md

Community

Endpoint	Description	Reference
GET /v1/community/trending/token	Trending tokens by community activity	community.md
GET /v1/community/trending/topic	Trending discussion topics	community.md

Content

Endpoint	Description	Reference
GET /v1/content/latest	Latest news and Alexandria articles	content.md
GET /v1/content/posts/comments	Comments on a specific post	content.md
GET /v1/content/posts/latest	Latest community posts	content.md
GET /v1/content/posts/top	Top ranked community posts	content.md

K-Line Charts

Endpoint	Description	Reference
GET /v1/k-line/candles	OHLCV candlestick data	kline.md
GET /v1/k-line/points	Time series price/market cap points	kline.md

Tools

Endpoint	Description	Reference
GET /v1/fiat/map	Map fiat currencies to CMC IDs	tools.md
GET /v1/key/info	API key usage and plan details	tools.md
GET /v2/tools/price-conversion	Convert between currencies	tools.md

Common Workflows

Get Market Sentiment Overview

1. Fetch fear/greed index: /v3/fear-and-greed/latest
2. Get global metrics: /v1/global-metrics/quotes/latest
3. Combine for sentiment analysis with market cap context

Track Market Index Performance

1. Get current CMC100 value: /v3/index/cmc100-latest
2. Fetch historical data: /v3/index/cmc100-historical
3. Compare performance over time

Monitor Community Activity

1. Check trending tokens: /v1/community/trending/token
2. Review trending topics: /v1/community/trending/topic
3. Read latest posts: /v1/content/posts/top

Build Price Charts

1. Fetch OHLCV candles: /v1/k-line/candles
2. Use interval parameter for timeframe (1h, 4h, 1d)
3. Plot candlestick chart with returned data

Currency Conversion

1. Get fiat currency IDs: /v1/fiat/map
2. Convert amounts: /v2/tools/price-conversion

Error Handling

Status Code	Meaning	Action
400	Bad Request	Check parameter values and format
401	Unauthorized	Verify API key is valid
403	Forbidden	Endpoint not available on your plan
429	Rate Limited	Wait and retry with backoff
500	Server Error	Retry after delay

Error Response Format

{
  "status": {
    "error_code": 400,
    "error_message": "Invalid value for 'id'"
  }
}

Rate Limit Headers

Check these response headers to monitor usage:

1. X-CMC_PRO_API_KEY_CREDITS_USED - Credits consumed
2. X-CMC_PRO_API_KEY_CREDITS_REMAINING - Credits left
3. X-CMC_PRO_API_KEY_RATE_LIMIT - Requests per minute limit

Response Format

All endpoints return JSON with this structure:

{
  "status": {
    "timestamp": "2024-01-15T10:30:00.000Z",
    "error_code": 0,
    "error_message": null,
    "credit_count": 1
  },
  "data": { }
}

Tips

1. Use the /v1/key/info endpoint to check your plan limits before heavy usage
2. Cache global metrics data as it updates every few minutes
3. Fear/greed index updates daily, no need for frequent polling
4. K-line data supports multiple intervals for different chart timeframes
5. Community trending data refreshes periodically throughout the day