# Holt-Winters Triple Exponential Smoothing Forecast

> Holt-Winters Triple Exponential Smoothing Forecast is a paid API for AI agents from agent402.tools, paid per call via x402, $0.001/call, status unknown (last checked 2026-09-14).

Forecasts future values of a time series with level, trend, and seasonal components using Holt-Winters triple exponential smoothing (additive or multiplicative seasonality).

## Facts

- Endpoint: POST https://agent402.tools/api/forecast-holt-winters
- Price: $0.001/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/holt-winters-triple-exponential-smoothing-forecast-b41ebd6f
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_ivbODzllVWzYK95B-1ww5

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability holt-winters-triple-exponential-smoothing-forecast-b41ebd6f -d '<json body>'
```

Example prompt: I have 104 weeks of weekly retail traffic data — can you run a Holt-Winters forecast on it with a period of 7, additive seasonality, alpha 0.4, beta 0.1, gamma 0.2, and predict the next 12 periods?

## When to prefer this

Choose this endpoint when your time series exhibits both a trend and a repeating seasonal cycle (e.g. weekly, monthly, quarterly patterns). It is preferable over simple or double exponential smoothing when seasonality is present, and preferable over ARIMA or ML-based approaches when you need a fast, interpretable, parameter-controlled forecast without training data requirements.

## Known failure modes

- Series too short relative to the seasonal period — insufficient data to estimate seasonal indices
- Invalid alpha/beta/gamma values outside (0,1) range — returns validation error
- Period auto-detection fails if the series lacks a clear repeating cycle — may return error or fallback estimate
- Horizon exceeds 1000 — returns out-of-range error
- Values array exceeds 10000 elements — returns payload too large error
- Multiplicative seasonality with zero or negative values causes division errors

## How this service works

Holt-Winters triple exponential smoothing - level + trend + seasonal component. Use for series with a repeating cycle (weekly retail traffic, monthly utility usage, quarterly revenue). Additive seasonality (constant amplitude) or multiplicative (amplitude grows with level). `period` is optional - if omitted, the kit auto-detects via autocorrelation on first differences and surfaces what it picked (with the ACF strength) so you can audit. Needs at least two full seasonal cycles to fit reliably.

## Output

Returns forecasted numeric values for the requested horizon, along with decomposed level, trend, and seasonal components derived from the Holt-Winters algorithm applied to the input series.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "beta": {
   "type": "number",
   "description": "Trend smoothing, 0 < beta < 1 (default 0.1)"
  },
  "alpha": {
   "type": "number",
   "description": "Level smoothing, 0 < alpha < 1 (default 0.5)"
  },
  "gamma": {
   "type": "number",
   "description": "Seasonal smoothing, 0 < gamma < 1 (default 0.1)"
  },
  "period": {
   "type": "number",
   "description": "Optional seasonal period (e.g. 7 for daily/weekly, 12 for monthly/yearly). Auto-detected via ACF if omitted."
  },
  "values": {
   "type": "array",
   "description": "Numeric series in chronological order (max 10000)"
  },
  "horizon": {
   "type": "number",
   "description": "Number of future periods to forecast (1 to 1000)"
  },
  "seasonality": {
   "type": "string",
   "description": "\"additive\" (default) or \"multiplicative\""
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "n": 12,
  "beta": 0.1,
  "alpha": 0.5,
  "gamma": 0.1,
  "method": "holt-winters",
  "period": 4,
  "horizon": 4,
  "forecast": [
   {
    "step": 1,
    "point": 12.5324,
    "lower95": 11.6958,
    "upper95": 13.369
   },
   {
    "step": 2,
    "point": 16.7253,
    "lower95": 15.5421,
    "upper95": 17.9084
   },
   {
    "step": 3,
    "point": 20.9462,
    "lower95": 19.4972,
    "upper95": 22.3952
   },
   {
    "step": 4,
    "point": 25.1831,
    "lower95": 23.5098,
    "upper95": 26.8563
   }
  ],
  "seasonality": "additive",
  "periodSource": "provided"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/holt-winters-triple-exponential-smoothing-forecast-b41ebd6f/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from agent402.tools](https://www.zero.xyz/host/agent402.tools/llms.txt)