Données de marché

API de sentiment crypto pour agents IA

L’indice Fear & Greed du marché crypto dans une seule API : une valeur de 0 à 100 par jour depuis 2018, avec sa classification, de la peur extrême à l’avidité extrême. Branchez le sentiment du marché dans vos modèles à côté du prix et des flux, avec la même clé et le même format. La même API sert aussi le Fear & Greed de CoinMarketCap, l’Altcoin Season Index et les indices CMC20 et CMC100.

L’indice de peur et d’avidité du marché crypto : une valeur de 0 à 100 par jour et sa classification, depuis 2018. Tout le marché : il n’accepte pas de symbole.

#Sentiment crypto pour agents IA et LLM

« Le marché est-il dans la peur ou l’avidité ? », « Est-ce la saison des altcoins ? », « Comment le CMC20 a-t-il évolué ce mois-ci ? » : un agent IA lit le sentiment du marché par l’outil MCP get_market_overview, qui ne demande aucune paire.

MCP tools/call

Les deux indices Fear & Greed et l’Altcoin Season Index en un appel MCP.

{
  "name": "get_market_overview",
  "arguments": {
    "fields": ["fear_greed", "fear_greed_cmc", "altcoin_season"]
  }
}

Pour le LLM : les deux indices Fear & Greed (alternative.me et CoinMarketCap) sont des indices différents, aux valeurs différentes : une réponse doit nommer celui qu’elle cite.
Pour les développeurs : /v1/fear-greed et /v1/altcoin-season font des outils petits et stables pour votre propre agent IA (tool calling), avec des étiquettes de extreme_fear à extreme_greed.
Où ça tourne : Claude, ChatGPT, Cursor et tout client MCP, y compris les frameworks d’agents qui parlent MCP, comme LangChain ou n8n.

Branchez votre agent IA avec le guide du serveur MCP, ou apprenez-lui BytNode avec les Agent Skills open source.

#Fear & Greed

GET/v1/fear-greeddata_type · fear_greedRéférence complète

Les 3 champs de cette route (d’après le contrat)

`time`	ISO 8601 UTC, milliseconds (2026-09-28T14:00:00.000Z)	The day the value refers to, at midnight UTC.
`value`	score from 0 to 100	Crypto Fear & Greed Index (alternative.me). 0 = extreme fear, 100 = extreme greed.
`label`		Label of the value, from alternative.me's scale: `extreme_fear`, `fear`, `neutral`, `greed` or `extreme_greed` (snake_case, like every label of the API).

GET/v1/fear-greed/historydata_type · fear_greed_historyRéférence complète

Les 4 champs de cette route (d’après le contrat)

`time`	ISO 8601 UTC, milliseconds (2026-09-28T14:00:00.000Z)	The day the value refers to, at midnight UTC.
`value`	score from 0 to 100	Crypto Fear & Greed Index (alternative.me). 0 = extreme fear, 100 = extreme greed.
`label`		Label of the value, from alternative.me's scale: `extreme_fear`, `fear`, `neutral`, `greed` or `extreme_greed` (snake_case, like every label of the API).
`is_closed`		`true` = the row is final; `false` = provisional: the latest bucket while it still settles (a few seconds after its end, e.g. a candle whose volumes are not final yet), or the period in progress with `?live=1` on the routes that take it. Exception, rare: when a venue delivers trades LATE (seconds to minutes, e.g. during a burst), a closed row built from trades (trade candles, candle volumes, CVD, buy/sell ratio, trades per second) is corrected afterwards to include them, usually within minutes and at most one hour later; the correction only adds the late trades.

L’indice de peur et d’avidité du marché crypto : une valeur de 0 à 100 et son label, de extreme_fear à extreme_greed (l’échelle d’alternative.me, en snake_case comme toute étiquette de BytNode). Tout le marché : il n’accepte pas de symbole.

Réponse

{
  "status": "ok",
  "server_time": "2026-11-08T12:51:51.873Z",
  "data_type": "fear_greed",
  "data": {
    "time": "2026-11-08T00:00:00.000Z",
    "value": 28,
    "label": "fear"
  }
}

Un point par jour

L’indice est publié une fois par jour, aligné sur minuit UTC. L’historique remonte à 2018, plus de trois mille points. L’interroger plus d’une fois par jour consomme du quota sans rien apprendre.

#Fear & Greed de CMC

GET/v1/fear-greed/cmcdata_type · fear_greed_cmcRéférence complète

Les 3 champs de cette route (d’après le contrat)

`time`	ISO 8601 UTC, milliseconds (2026-09-28T14:00:00.000Z)	Point-in-time value: the instant of the measurement (when the source was read).
`value`	score from 0 to 100	CMC Crypto Fear & Greed Index (CoinMarketCap), a different index from `/v1/fear-greed` (alternative.me). 0 = extreme fear, 100 = extreme greed.
`label`		Label of the value, from CoinMarketCap's scale: `extreme_fear`, `fear`, `neutral`, `greed` or `extreme_greed` (snake_case, like every label of the API).

GET/v1/fear-greed/cmc/historydata_type · fear_greed_cmc_historyRéférence complète

Les 4 champs de cette route (d’après le contrat)

`time`	ISO 8601 UTC, milliseconds (2026-09-28T14:00:00.000Z)	The day the value refers to, at midnight UTC.
`value`	score from 0 to 100	CMC Crypto Fear & Greed Index (CoinMarketCap), a different index from `/v1/fear-greed` (alternative.me). 0 = extreme fear, 100 = extreme greed.
`label`		Label of the value, from CoinMarketCap's scale: `extreme_fear`, `fear`, `neutral`, `greed` or `extreme_greed` (snake_case, like every label of the API).
`is_closed`		`true` = the row is final; `false` = provisional: the latest bucket while it still settles (a few seconds after its end, e.g. a candle whose volumes are not final yet), or the period in progress with `?live=1` on the routes that take it. Exception, rare: when a venue delivers trades LATE (seconds to minutes, e.g. during a burst), a closed row built from trades (trade candles, candle volumes, CVD, buy/sell ratio, trades per second) is corrected afterwards to include them, usually within minutes and at most one hour later; the correction only adds the late trades.

L’indice de peur et d’avidité propre à CoinMarketCap, un autre indice que celui ci-dessus : une valeur de 0 à 100 et son label (extreme_fear à extreme_greed). La valeur courante est rafraîchie dans la journée ; /history donne un point par jour à minuit UTC depuis 2023.

Réponse

{
  "status": "ok",
  "server_time": "2026-11-08T12:51:52.886Z",
  "data_type": "fear_greed_cmc",
  "data": {
    "time": "2026-11-08T12:38:10.041Z",
    "value": 32,
    "label": "fear"
  }
}

#Altcoin Season Index

GET/v1/altcoin-seasondata_type · altcoin_seasonRéférence complète

Les 7 champs de cette route (d’après le contrat)

`time`	ISO 8601 UTC, milliseconds (2026-09-28T14:00:00.000Z)	Point-in-time value: the instant of the measurement (when the source was read).
`value`	score from 0 to 100	Altcoin Season Index (CoinMarketCap): how many of the top altcoins outperformed BTC over the last 90 days. High = altcoin season, low = bitcoin season.
`year_low`	score from 0 to 100	Lowest value of the index over the last year.
`year_high`	score from 0 to 100	Highest value of the index over the last year.
`year_low_at`	ISO 8601 UTC, milliseconds (2026-09-28T14:00:00.000Z)	Day of that lowest value, at midnight UTC.
`year_high_at`	ISO 8601 UTC, milliseconds (2026-09-28T14:00:00.000Z)	Day of that highest value, at midnight UTC.
`altcoin_market_cap_usd`	USD	Total market capitalisation of the altcoins (excluding BTC).

GET/v1/altcoin-season/historydata_type · altcoin_season_historyRéférence complète

Les 4 champs de cette route (d’après le contrat)

`time`	ISO 8601 UTC, milliseconds (2026-09-28T14:00:00.000Z)	The day the value refers to, at midnight UTC.
`value`	score from 0 to 100	Altcoin Season Index (CoinMarketCap): how many of the top altcoins outperformed BTC over the last 90 days. High = altcoin season, low = bitcoin season.
`altcoin_market_cap_usd`	USD	Total market capitalisation of the altcoins (excluding BTC).
`is_closed`		`true` = the row is final; `false` = provisional: the latest bucket while it still settles (a few seconds after its end, e.g. a candle whose volumes are not final yet), or the period in progress with `?live=1` on the routes that take it. Exception, rare: when a venue delivers trades LATE (seconds to minutes, e.g. during a burst), a closed row built from trades (trade candles, candle volumes, CVD, buy/sell ratio, trades per second) is corrected afterwards to include them, usually within minutes and at most one hour later; the correction only adds the late trades.

Qui mène, les altcoins ou le bitcoin : de 0 (saison du bitcoin) à 100 (saison des altcoins), avec altcoin_market_cap_usd et les extrêmes sur un an (year_high, year_low et leurs dates). /history donne un point par jour, depuis les 90 derniers jours.

Réponse

{
  "status": "ok",
  "server_time": "2026-11-08T12:51:53.925Z",
  "data_type": "altcoin_season",
  "data": {
    "time": "2026-11-08T12:38:27.000Z",
    "value": 38,
    "year_low": 14,
    "year_high": 64,
    "year_low_at": "2025-12-19T00:00:00.000Z",
    "year_high_at": "2026-09-27T00:00:00.000Z",
    "altcoin_market_cap_usd": 1016577631975
  }
}

#Indices CMC20 et CMC100

GET/v1/indices/cmc20data_type · indices_cmc20Référence complète

Les 7 champs de cette route (d’après le contrat)

`time`	ISO 8601 UTC, milliseconds (2026-09-28T14:00:00.000Z)	Point-in-time value: the instant of the measurement (when the source was read).
`value`	index points	CoinMarketCap 20 Index: the 20 largest crypto assets, weighted by market capitalisation.
`constituents`		The assets of the index, with their weight.
`constituents.name`		Asset name (`Bitcoin`).
`constituents.asset`		Asset symbol (`BTC`).
`constituents.weight_pct`	percent (58.5 = 58.5 %)	Weight of the asset in the index (70.9 = 70.9 %).
`change_24h_pct`	percent (58.5 = 58.5 %)	Change of the index over the last 24 hours.

GET/v1/indices/cmc20/historydata_type · indices_cmc20_historyRéférence complète

Les 3 champs de cette route (d’après le contrat)

`time`	ISO 8601 UTC, milliseconds (2026-09-28T14:00:00.000Z)	The day the value refers to, at midnight UTC.
`value`	index points	CoinMarketCap 20 Index: the 20 largest crypto assets, weighted by market capitalisation.
`is_closed`		`true` = the row is final; `false` = provisional: the latest bucket while it still settles (a few seconds after its end, e.g. a candle whose volumes are not final yet), or the period in progress with `?live=1` on the routes that take it. Exception, rare: when a venue delivers trades LATE (seconds to minutes, e.g. during a burst), a closed row built from trades (trade candles, candle volumes, CVD, buy/sell ratio, trades per second) is corrected afterwards to include them, usually within minutes and at most one hour later; the correction only adds the late trades.

GET/v1/indices/cmc100data_type · indices_cmc100Référence complète

Les 7 champs de cette route (d’après le contrat)

`time`	ISO 8601 UTC, milliseconds (2026-09-28T14:00:00.000Z)	Point-in-time value: the instant of the measurement (when the source was read).
`value`	index points	CoinMarketCap 100 Index: the 100 largest crypto assets, weighted by market capitalisation.
`constituents`		The assets of the index, with their weight.
`constituents.name`		Asset name (`Bitcoin`).
`constituents.asset`		Asset symbol (`BTC`).
`constituents.weight_pct`	percent (58.5 = 58.5 %)	Weight of the asset in the index (67.9 = 67.9 %).
`change_24h_pct`	percent (58.5 = 58.5 %)	Change of the index over the last 24 hours.

GET/v1/indices/cmc100/historydata_type · indices_cmc100_historyRéférence complète

Les 3 champs de cette route (d’après le contrat)

`time`	ISO 8601 UTC, milliseconds (2026-09-28T14:00:00.000Z)	The day the value refers to, at midnight UTC.
`value`	index points	CoinMarketCap 100 Index: the 100 largest crypto assets, weighted by market capitalisation.
`is_closed`		`true` = the row is final; `false` = provisional: the latest bucket while it still settles (a few seconds after its end, e.g. a candle whose volumes are not final yet), or the period in progress with `?live=1` on the routes that take it. Exception, rare: when a venue delivers trades LATE (seconds to minutes, e.g. during a burst), a closed row built from trades (trade candles, candle volumes, CVD, buy/sell ratio, trades per second) is corrected afterwards to include them, usually within minutes and at most one hour later; the correction only adds the late trades.

Les deux indices de marché de CoinMarketCap, des 20 et des 100 plus grands actifs crypto : value, change_24h_pct et chaque composant avec son poids (asset, name, weight_pct). /history donne une valeur par jour depuis janvier 2024.

Réponse

{
  "status": "ok",
  "server_time": "2026-11-08T12:51:54.955Z",
  "data_type": "indices_cmc20",
  "data": {
    "time": "2026-11-08T12:42:35.000Z",
    "value": 154.95,
    "constituents": [
      {
        "name": "Bitcoin",
        "asset": "BTC",
        "weight_pct": 70.89
      },
      {
        "name": "Ethereum",
        "asset": "ETH",
        "weight_pct": 12.7
      },
      {
        "name": "BNB",
        "asset": "BNB",
        "weight_pct": 4.27
      }
    ],
    "change_24h_pct": -0.05
  }
}