# ARM Payment Shock Calculator

> ARM Payment Shock Calculator is a paid API for AI agents from x402toll.com, paid per call via x402, $0.05/call, status unknown (last checked 2026-09-14).

Calculates adjustable-rate mortgage (ARM) payments before and after the first rate reset, showing the payment increase (payment shock) at adjustment.

## Facts

- Endpoint: POST https://x402toll.com/v1/realestate/arm
- Price: $0.05/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/arm-payment-shock-calculator-5bcc7a81
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_-W0iQEFV8wpGx-Ev_D0EK

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 arm-payment-shock-calculator-5bcc7a81 -d '<json body>'
```

Example prompt: I have a $450,000 ARM loan with a 30-year term, currently at a 5.5% initial rate for the first 60 months — when it resets to 7.25%, how much will my monthly payment jump?

## When to prefer this

Use this endpoint when a user wants to understand the financial impact of an ARM rate reset — specifically the before/after monthly payment and how much the payment will increase. Ideal for home buyers evaluating ARM vs fixed-rate loans, or existing ARM holders approaching their reset date.

## Known failure modes

- Missing required fields (loanAmount, initialRatePct, adjustedRatePct) returns a 400 error
- Negative or zero loan amount causes invalid computation
- Rate values out of realistic range may return unexpected results
- fixedPeriodMonths greater than termMonths is an invalid input

## How this service works

Adjustable-rate mortgage payment shock: the payment before and after the first reset, and the increase.

## Output

Returns the monthly mortgage payment during the initial fixed period, the new monthly payment after the first rate reset, and the dollar amount of the increase — giving a clear picture of payment shock at adjustment.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "loanAmount": {
   "type": "number"
  },
  "termMonths": {
   "type": "number",
   "default": 360
  },
  "initialRatePct": {
   "type": "number"
  },
  "adjustedRatePct": {
   "type": "number"
  },
  "fixedPeriodMonths": {
   "type": "number"
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/arm-payment-shock-calculator-5bcc7a81/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from x402toll.com](https://www.zero.xyz/host/x402toll.com/llms.txt)