# Unit Return Rate – Adjacent Period Changes

> Unit Return Rate – Adjacent Period Changes is a paid API for AI agents from market.datapackvibe.com, paid per call via x402, $0.01/call, status unknown (last checked 2026-10-27).

Calculates period-over-period changes in unit return rates from supplied retail sold and returned units data.

## Facts

- Endpoint: POST https://market.datapackvibe.com/x402/assistant-sector-retail-unit-return-period-changes?utm_source=zero.xyz
- Price: $0.01/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-27
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/unit-return-rate-adjacent-period-changes-fe4cb14e
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_kTQTnC0yhMDdXbf8L5hAF

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 unit-return-rate-adjacent-period-changes-fe4cb14e -d '<json body>'
```

Example prompt: Can you calculate the adjacent period changes in unit return rate for these four periods: period 1 had 100 units sold and 5 returned, period 2 had 110 sold and 5.5 returned, period 3 had 100 sold and 5 returned, period 4 had 110 sold and 5.5 returned?

## When to prefer this

Choose this endpoint when you need a fast, local computation of period-over-period unit return rate changes from raw retail sold/returned figures — no live data access, no account integration required. Ideal for scenario modeling, historical trend analysis, or batch comparisons of up to 200 period rows at $0.01 per call.

## Known failure modes

- Fewer than 2 rows supplied — minimum 2 periods required for adjacent comparison
- sold_units of 0 or missing — division by zero not allowed (exclusiveMinimum enforced)
- More than 200 rows supplied — exceeds maxItems limit
- returned_units exceeds sold_units — may produce return rates above 100%, accepted but may be logically unexpected
- Non-numeric values in rows — schema validation failure

## How this service works

Unit return rate - Adjacent period changes: Adjacent period changes for Unit return rate. Supplied retail figures only. Local calculation and scenario analysis; no live inventory, account access, platform fee lookup or order execution. One of 25 profiles or calculations across 20 shared operations in this sector. 0.01 USDC includes one bounded adjacent period changes deliverable.

## Output

Returns the computed adjacent period changes for unit return rate across the supplied rows of sold and returned units — showing how the return rate (returned_units / sold_units) shifted between each consecutive period pair.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "rows": {
   "type": "array",
   "items": {
    "type": "object",
    "required": [
     "returned_units",
     "sold_units"
    ],
    "properties": {
     "sold_units": {
      "type": "number",
      "default": 100,
      "maximum": 1000000000000,
      "minimum": 0,
      "exclusiveMinimum": 0
     },
     "returned_units": {
      "type": "number",
      "default": 5,
      "maximum": 1000000000000,
      "minimum": 0
     }
    },
    "additionalProperties": false
   },
   "default": [
    {
     "sold_units": 100,
     "returned_units": 5
    },
    {
     "sold_units": 110.00000000000001,
     "returned_units": 5.5
    },
    {
     "sold_units": 100,
     "returned_units": 5
    },
    {
     "sold_units": 110.00000000000001,
     "returned_units": 5.5
    }
   ],
   "maxItems": 200,
   "minItems": 2
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/unit-return-rate-adjacent-period-changes-fe4cb14e/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from market.datapackvibe.com](https://www.zero.xyz/host/market.datapackvibe.com/llms.txt)