# Free Small Biz Tools Late-Fee Reminder Email Generator

> Free Small Biz Tools Late-Fee Reminder Email Generator is a paid API for AI agents from api.freesmallbiztools.com, paid per call via x402, $0.01/call, status unknown (last checked 2026-10-15).

Calculates the late fee on an overdue invoice and generates a ready-to-send reminder email (subject + body) in polite, firm, or final tone.

## Facts

- Endpoint: GET https://api.freesmallbiztools.com/v1/late-fee-notice?utm_source=zero.xyz
- Price: $0.01/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/free-small-biz-tools-late-fee-reminder-email-generator-c250f94c
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_ae2w8fD1rlhyYClLrN0RY

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 free-small-biz-tools-late-fee-reminder-email-generator-c250f94c
```

Example prompt: Draft a polite late-fee reminder email for my client Acme Corp — invoice #INV-2024 for $1,800 that was due on 2025-05-01, with a 1.5% monthly late fee and a 5-day grace period. My business name is Bloom Studio.

## When to prefer this

Choose this endpoint when you need to automatically generate a professional, tone-calibrated late-fee reminder email without building the calculation or copy logic yourself. It is ideal for small business automation workflows, freelance billing agents, or any scenario where the agent needs to produce a human-ready overdue notice including a computed late fee in a single API call.

## Known failure modes

- 400 Bad Request when required parameters (amount or due_date) are missing or malformed
- 400 returned for invalid date formats (must be YYYY-MM-DD)
- 400 returned for unsupported rate_type or tone enum values
- Invalid numeric strings for amount or rate may trigger 400
- No actual email is sent — the endpoint only generates the copy

## How this service works

Free Small Biz Tools API: Late-fee reminder email for an overdue invoice. Calculates the late fee and writes a ready-to-send reminder (subject + body) in a polite, firm or final tone. Bad input 400, never charged.

## Output

Returns a JSON object with the notice kind, tone, and a ready-to-send email containing a subject line and full body text. The body includes the calculated late fee amount, days overdue, and a professional message tailored to the requested tone (polite, firm, or final).

## 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": [
      "GET"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "required": [
      "amount",
      "due_date"
     ],
     "properties": {
      "rate": {
       "type": "string",
       "description": "Rate number (default 1.5)"
      },
      "tone": {
       "enum": [
        "polite",
        "firm",
        "final"
       ],
       "type": "string"
      },
      "amount": {
       "type": "string",
       "description": "Invoice amount, e.g. 1200"
      },
      "due_date": {
       "type": "string",
       "description": "YYYY-MM-DD"
      },
      "paid_date": {
       "type": "string",
       "description": "YYYY-MM-DD (default today)"
      },
      "rate_type": {
       "enum": [
        "monthly_percent",
        "annual_percent",
        "daily_percent",
        "flat"
       ],
       "type": "string"
      },
      "grace_days": {
       "type": "string"
      },
      "client_name": {
       "type": "string"
      },
      "business_name": {
       "type": "string"
      },
      "invoice_number": {
       "type": "string"
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object"
    }
   }
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "kind": "late_fee_notice",
  "tone": "polite",
  "email": {
   "body": "Hi there, ...",
   "subject": "Friendly reminder: your invoice was due 2026-09-01"
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/free-small-biz-tools-late-fee-reminder-email-generator-c250f94c/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from api.freesmallbiztools.com](https://www.zero.xyz/host/api.freesmallbiztools.com/llms.txt)