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  2. Market Sentiment

Fear and Greed index

GET /fear-greed-index
GetFearGreedIndex

A daily 0–100 fear-versus-greed reading for one asset, combining price, volatility, momentum, trading volume, and social mood: up to 20 Extreme Fear, 40 Fear, 60 Neutral, 80 Greed, above 80 Extreme Greed. metadata lists the components.

Wallet payment available at https://nebula-api.hiddensystems.ai/api/v1/x402/fear-greed-index. No Nebula account or API key required; check the payment offer before signing. x402 payment guide.

Parameters

asset_id string QUERY required

Asset ID from /assets or /search, such as NVDA, GLD, SPX, or bitcoin. Send it with the asset_class returned alongside it.

Example:NVDA

asset_class string QUERY required

Class of the asset named by asset_id: equity (stocks and ETFs), commodity, index, or crypto. Send the asset_class that /assets or /search returned alongside the asset_id.

Allowed values
equitycommodityindexcrypto

Example:equity

hours integer QUERY

Lookback window in hours. Free plans reach back 90 days; further returns 403.

Default:720

granularity string QUERY

Requested time-series bucket size. When omitted, the service chooses a bucket size appropriate for the lookback window.

Allowed values
1h2h4h12h1d

Example:1h

cURL Example

curl --get \
  --url 'https://nebula-api.hiddensystems.ai/api/v1/public/fear-greed-index' \
  --data-urlencode 'asset_id=NVDA' \
  --data-urlencode 'asset_class=equity' \
  --header 'X-API-Key: YOUR_API_KEY'

Responses

200 OK
400 Bad Request
401 Unauthorized
402 Credits used up; response includes renewal timing and purchased credit balance
403 Forbidden
404 Not Found
405 Method not allowed; the Allow header lists the supported method
429 Too Many Requests
500 Internal Server Error
503 Service Unavailable

Media type application/json

current
object required

Most recent value for each returned series or the current index reading.
current.index
number (double) required

Nebula index value on a 0–100 scale.

current.label
string required

Human-readable bucket or index label.

metadata
object optional

Methodology and request-window metadata needed to interpret the response.
metadata.components
array<object> required

Weighted components used to calculate the index.
metadata.components[].description
string required

Human-readable explanation of this component.

metadata.components[].name
string required

Human-readable name.

metadata.components[].weight
number (double) required

Component weight as a decimal fraction.

metadata.hours
integer required

Lookback window represented by the response, in hours.

metadata.labels
array<string> required

Ordered labels used to interpret index ranges.

metadata.scale
string required

Published scale or interpretation of the metric.

series
array<object> required

Chronologically ordered observations.
series[].index
number (double) required

Nebula index value on a 0–100 scale.

series[].label
string required

Human-readable bucket or index label.

series[].timestamp
string (date-time) required

UTC RFC 3339 timestamp for the observation or bucket start.

{
  "current": {
    "index": 67.4,
    "label": "Greed"
  },
  "series": [
    {
      "index": 67.4,
      "label": "Greed",
      "timestamp": "2026-08-07T15:00:00Z"
    }
  ]
}