# HALOWERK Price Elasticity Estimator

> HALOWERK Price Elasticity Estimator is a paid API for AI agents from handel.halowerk.com, paid per call via x402, $0.005/call, status unknown (last checked 2026-10-10).

Fits a log-log (constant-elasticity) demand curve to historical price and sales data and returns elasticity, standard error, t-statistic, p-value, and Student-t confidence intervals, plus optional contribution-optimal price and price grid evaluation.

## Facts

- Endpoint: POST https://handel.halowerk.com/v1/price-elasticity?utm_source=zero.xyz
- Price: $0.005/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-10
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/halowerk-price-elasticity-estimator-0e998044
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap__T0yj8kvYVYEdlgwsQDsj

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 halowerk-price-elasticity-estimator-0e998044 -d '<json body>'
```

Example prompt: Using my sales history for our coffee capsule SKU — 8 weekly observations at prices between €4.50 and €7.00 with units sold ranging from 320 to 890 — fit a constant-elasticity demand curve and tell me the elasticity, its 95% Student-t confidence interval, and the contribution-optimal price given a variable unit cost of €1.80.

## When to prefer this

Choose this endpoint when you need a statistically rigorous, constant-elasticity demand estimate backed by Student-t (not normal) confidence intervals — especially critical at small sample sizes (under ~30 observations) where normal approximations meaningfully understate uncertainty. Prefer it over manual regression when you also need promotion-period controls, competitor price controls, a contribution-optimal price recommendation, or evaluation of a candidate price grid, all in a single call. It is purpose-built for single-SKU pricing analysis from your own historical data, not for cross-sectional market research or real-time demand signals.

## Known failure modes

- Fewer than 4 observations supplied — minimum required for a meaningful fit
- All prices identical — log-log regression requires price variation
- Zero units_sold in all periods — no non-zero observations to fit
- Negative or zero prices supplied — logarithm is undefined
- Insufficient degrees of freedom for requested confidence level
- Competitor price or promotion flag provided but corresponding option flag not enabled in request
- Currency code not exactly 3 uppercase ISO 4217 characters
- Payment not confirmed via x402 — 402 Payment Required returned

## How this service works

Fits a constant-elasticity demand curve to the price and sales series you supply and returns the elasticity with its standard error, t statistic, two-sided p value and a Student t confidence interval, not a normal one, because at eight observations the difference in interval width is double-digit percent and a too narrow interval is exactly the kind of number a machine reuses unchecked.

## Output

Returns the estimated price elasticity coefficient, its standard error, t-statistic, two-sided p-value, and a Student-t confidence interval at the requested level. If unit_cost is provided, also returns the contribution-optimal price. If price_grid is provided, returns predicted units sold and contribution margin at each candidate price. Zero-unit observations are excluded and reported explicitly rather than silently dropped.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "currency": {
   "type": "string",
   "default": "EUR",
   "maxLength": 3,
   "minLength": 3,
   "description": "ISO 4217 code for every amount in this request. Not converted, only carried through."
  },
  "unit_cost": {
   "type": "number",
   "maximum": 100000000,
   "minimum": 0,
   "description": "Variable cost per unit. Required for the contribution-optimal price; without it only the elasticity is returned."
  },
  "price_grid": {
   "type": "array",
   "items": {
    "type": "number",
    "maximum": 100000000,
    "exclusiveMinimum": 0
   },
   "maxItems": 200,
   "description": "Candidate prices to evaluate with predicted units and contribution. Evaluated at the fitted model, in the order you give them."
  },
  "observations": {
   "type": "array",
   "items": {
    "type": "object",
    "required": [
     "price",
     "units_sold"
    ],
    "properties": {
     "price": {
      "type": "number",
      "maximum": 100000000,
      "description": "Selling price in that period. Must be positive: the estimation is on logarithms.",
      "exclusiveMinimum": 0
     },
     "promotion": {
      "type": "boolean",
      "default": false,
      "description": "Whether the period was a promotion. Enters the fit as a separate indicator when include_promotion is true, so that a campaign is not attributed to the price."
     },
     "units_sold": {
      "type": "number",
      "maximum": 1000000000,
      "minimum": 0,
      "description": "Units sold at that price. A zero cannot enter a log-log fit and is excluded, reported and never silently dropped."
     },
     "period_start": {
      "type": "string",
      "pattern": "^\\d{4}-\\d{2}-\\d{2}$",
      "description": "Optional period label as YYYY-MM-DD, passed through unchanged."
     },
     "competitor_price": {
      "type": "number",
      "maximum": 100000000,
      "description": "Competitor price in that period. Only used when include_competitor_price is true; you bring the figure, nothing is looked up.",
      "exclusiveMinimum": 0
     }
    },
    "additionalProperties": false
   },
   "maxItems": 2000,
   "minItems": 4,
   "description": "Your own price and sales history for one SKU. Every amount is in the currency named at document level."
  },
  "confidence_level": {
   "enum": [
    0.8,
    0.9,
    0.95
   ],
   "type": "number",
   "default": 0.95,
   "description": "Confidence level for the elasticity interval. Student t, not normal."
  },
  "inclu
… (truncated)
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/halowerk-price-elasticity-estimator-0e998044/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from handel.halowerk.com](https://www.zero.xyz/host/handel.halowerk.com/llms.txt)