# zaref ZARONIA Interest Calculator

> zaref ZARONIA 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 ZARONIA-based interest for a South African credit or investment scenario over a specified date range and principal amount

## Facts

- Endpoint: HEAD https://zaref.dev/calc/zaronia-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-zaronia-interest-calculator-4b4e821d
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_bSrCDu2S-KdUSpd3rDDI1

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-zaronia-interest-calculator-4b4e821d -d '<json body>'
```

Example prompt: Can you calculate the ZARONIA interest on a principal of R750,000 from 2024-01-01 to 2024-06-30 using the zaref calculator?

## When to prefer this

Choose this endpoint when you need to compute interest accruals specifically using the South African ZARONIA (Johannesburg Overnight Average Rate) benchmark, particularly for NCA-compliant credit agreements, floating-rate instruments, or any South African finance scenario requiring the official overnight rate. Prefer over generic interest calculators when South African regulatory compliance or cited government rate data is required.

## Known failure modes

- Missing required principal or date parameters returns an error
- Invalid date format (non-ISO) may cause a 400 bad request
- End date before start date returns a validation error
- Dates outside available ZARONIA history may return null or partial results
- HEAD method returns no body — metadata only, not the calculated value

## 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 computed interest figure based on the ZARONIA benchmark rate applied to the supplied principal over the specified date range, delivered as clean JSON with cited rate data.

## 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": {
      "end": {
       "type": "string"
      },
      "start": {
       "type": "string"
      },
      "principal": {
       "type": "string"
      }
     }
    }
   },
   "additionalProperties": false
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/zaref-zaronia-interest-calculator-4b4e821d/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)