Choosing fields with select

/quotes, /assets, /rwa and /dex/tokens take an optional select: a comma-separated list of the row fields you want. Each row of items then carries those fields and id, and nothing else.

curl -H "X-Api-Key: <your-api-key>" \
  "https://open-api.coinworldcap.com/openapi/v1/quotes?slug=bitcoin&select=price,percent_change"

{
  "code": 0,
  "message": "success",
  "message_key": "SUCCESS",
  "result": {
    "items": [
      {
        "id": 1,
        "price": "66079.916784987",
        "percent_change": { "1h": "0.1", "24h": "1.2", "7d": "3.4", "30d": "5.6", "3m": "7.8", "1y": "9", "ytd": "1.1", "all": "2.2" }
      }
    ],
    "page": 1,
    "total_page": 1,
    "total": 1
  }
}

• Only the rows are trimmed. page, total and total_page are unchanged, and so are /dex/tokens' list, window, data_time, stale and filters. Without select the response is exactly what it is today.
• id is always there, whether you name it or not. On /dex/tokens it is the token's own id, a string; to call the other /dex endpoints for a token, select chain_slug and address too.
• Names are the row fields in the endpoint's field table, top level only. A nested object or array — percent_change, windows, links, platforms, explorers — comes whole; there is no percent_change.24h.
• A name the endpoint's rows do not have is a 400, code 40000: a typo, a dotted path, or a field of another endpoint (liquidity on /quotes). This is unlike other parameters, where a name we do not read is ignored (Check parameter names) — here an ignored name would answer rows of nothing but id.
• At most 100 names, counted after splitting: empty items are dropped and a repeated name counts each time. More is a 400.
• Names are case-insensitive and surrounding spaces are trimmed. select= with nothing in it is the same as no select.
• Sorting and filtering are unaffected. You can sort by a field you did not select; the rows and their order are the same as without select.
• A field that may be absent stays absent. A row with no rank has none when you select rank; it is not filled in as null.
• On /assets, fields comes first. fields adds links or platforms to the row, then select trims it: fields=links&select=name,links gives id, name and links. Selecting links or platforms without the matching fields value is a 400. fields itself is unchanged, and still ignores names it does not know.