# Today's flow vs trailing average (with similar-days lookback)

`GET https://flow-api.skylit.ai/v1/flow/{ticker}/historical-compare`

API: Flowseeker.

Compares the current trading day's premium / volume / net premium /
call-put ratio against the trailing 20-trading-day average for the
same ticker. Returns absolute deltas, percentile rankings, and the
five most-similar past trading days.

## Authentication

Send your Skylit API key as a bearer token: `Authorization: Bearer <key>`. No other header is accepted.

## Parameters

| Name | In | Type | Required | Description |
| --- | --- | --- | --- | --- |
| `ticker` | path | string | yes | Underlying ticker symbol (uppercase, e.g. `SPY`, `AAPL`). |
| `date` | query | string (date) | no | Date to evaluate (YYYY-MM-DD). Defaults to today. |

## Example request

```bash
curl "https://flow-api.skylit.ai/v1/flow/SPY/historical-compare" \
  -H "Authorization: Bearer $SKYLIT_API_KEY"
```

## Responses

### 200

Today vs historical comparison.

Shape (placeholder values):

```json
{
  "data": {
    "ticker": "string",
    "date": "string",
    "current": {
      "totalPremium": 0,
      "totalVolume": 0,
      "callPremium": 0,
      "putPremium": 0,
      "netPremium": 0,
      "callPutRatio": 0,
      "callVolume": 0,
      "putVolume": 0
    },
    "historical": {
      "avgPremium": 0,
      "avgVolume": 0,
      "avgNetPremium": 0,
      "avgCallPutRatio": 0,
      "avgCallPremium": 0,
      "avgPutPremium": 0,
      "daysAnalyzed": 0
    },
    "vsAverage": {
      "premiumVsAvg": 0,
      "volumeVsAvg": 0,
      "netPremiumVsAvg": 0
    },
    "percentileRankings": {
      "premiumPercentile": 0,
      "volumePercentile": 0,
      "netPremiumPercentile": 0
    },
    "similarDays": [
      {
        "date": "string",
        "netPremium": 0,
        "totalPremium": 0,
        "similarityScore": 0
      }
    ]
  },
  "meta": {
    "timestamp": "string",
    "requestId": "d7574836"
  }
}
```

### 400

Request validation failed.

invalidParam:

```json
{
  "error": {
    "code": "BAD_REQUEST",
    "message": "Invalid parameter 'timeframe': must be one of [1m, 5m, 15m, 1h, 4h, 1d, 1w, 1M]"
  }
}
```

### 401

Missing or invalid API key.

missingKey:

```json
{
  "error": {
    "code": "UNAUTHORIZED",
    "message": "Authentication required"
  }
}
```

### 402

The account's shared Skylit credit balance is lower than this route's cost. Top up to continue. Carries `X-Credits-Remaining: 0`.

Headers: `X-Credits-Remaining`.

outOfCredits:

```json
{
  "error": {
    "code": "insufficient_credits",
    "message": "Out of credits. Top up to continue making requests."
  }
}
```

### 403

API key invalid, revoked or expired, or the account's API access is suspended (`account_suspended`).

accountSuspended:

```json
{
  "error": {
    "code": "account_suspended",
    "message": "API access has been suspended for this account. Contact support."
  }
}
```

### 404

Unknown resource (ticker / sector / window with no data).

noData:

```json
{
  "error": {
    "code": "NOT_FOUND",
    "message": "No trades found for AAPL on 2026-05-27 with timeframe 1d"
  }
}
```

### 429

Per-minute rate limit exceeded.

Headers: `Retry-After`.

tooFast:

```json
{
  "error": {
    "code": "RATE_LIMITED",
    "message": "Rate limit of 100 req/min exceeded. Retry after 18s."
  }
}
```

### 503

Underlying data source temporarily unavailable, or the credit balance could not be verified (`credit_check_failed`). Safe to retry.

ingestionLag:

```json
{
  "error": {
    "code": "UNAVAILABLE",
    "message": "Live feed is degraded; please retry in a few seconds."
  }
}
```

creditCheckFailed:

```json
{
  "error": {
    "code": "credit_check_failed",
    "message": "Could not verify credit balance. Please retry."
  }
}
```