# zaref Local Interest Calculator

> zaref Local Interest Calculator is a paid API for AI agents from zaref.dev, paid per call via x402, $0.01/call, status unknown (last checked 2026-10-23).

Calculates South African local/prescribed interest for a given principal amount and age of debt under South African NCA and SARS rules

## Facts

- Endpoint: HEAD https://zaref.dev/calc/local-interest?utm_source=zero.xyz
- Price: $0.01/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-23
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/zaref-local-interest-calculator-8cb4460e
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_zWw_oyvSRGOqEvE42YuuN

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 zaref-local-interest-calculator-8cb4460e -d '<json body>'
```

Example prompt: Can you calculate the local interest owed on a R50,000 debt that is 18 months old using South African prescribed rates?

## When to prefer this

Use this endpoint when you need a fast, cited, regulation-aware computation of South African local (prescribed) interest on a debt amount and age, without building your own rate-lookup and formula logic. Prefer it over generic interest calculators when South African NCA or SARS prescribed rates are required.

## Known failure modes

- Missing required 'amount' or 'age' query parameters returns an error or empty result
- Invalid non-numeric values for amount or age cause a bad request response
- Stale rate data if underlying SARS/NCA rate has not yet been updated after a regulatory change
- HEAD method returns no body — only status code and headers, limiting data retrieval

## How this service works

South African reference data as clean, cited JSON: fuel prices, interest rates, FX and bond yields, tax tables, tariffs, wages and grants, live government tenders and crypto prices, plus calculators. Built for AI agents and applications.

## Output

Returns a JSON object containing the calculated local interest amount in ZAR, the applicable prescribed interest rate used, and a breakdown of the computation based on the supplied principal amount and debt age, all cited against current South African regulatory sources.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "HEAD"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "properties": {
      "age": {
       "type": "string"
      },
      "amount": {
       "type": "string"
      }
     }
    }
   },
   "additionalProperties": false
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/zaref-local-interest-calculator-8cb4460e/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from zaref.dev](https://www.zero.xyz/host/zaref.dev/llms.txt)