Free Small Biz Tools API
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.
Not tested: has real-world effectsour last check, 2026-10-18
0 of 0checks answered this week
n/amedian answer time
$0.01listed price per call
n/aprice it asked us
Paid test badge: not yet. The checks above are free: we call the tool without paying and read the payment request it sends back. The Verified badge needs paid calls whose answers match the promised output, and nobody can buy a badge.
Endpoint
GET https://api.freesmallbiztools.com/v1/late-fee-notice
| Category | Everything else |
|---|---|
| Provider host | api.freesmallbiztools.com |
| Networks | eip155:8453 |
| Payment schemes | exact |
| Self-reported calls, 30 days | 2 from 2 payers (the provider's figure, not ours) |
Our checks, last 30 days
We never call tools that send, buy, move money or file anything, not even without paying.
Example input (from the provider)
{
"method": "GET",
"queryParams": {
"amount": "1200",
"due_date": "2026-09-01",
"paid_date": "2026-10-14",
"rate": "1.5",
"rate_type": "monthly_percent",
"tone": "polite"
},
"type": "http"
}
Promised output schema (from the provider)
{
"$schema": "https://json-schema.org/draft/2020-12/schema",
"properties": {
"input": {
"additionalProperties": false,
"properties": {
"method": {
"enum": [
"GET"
],
"type": "string"
},
"queryParams": {
"properties": {
"amount": {
"description": "Invoice amount, e.g. 1200",
"type": "string"
},
"business_name": {
"type": "string"
},
"client_name": {
"type": "string"
},
"due_date": {
"description": "YYYY-MM-DD",
"type": "string"
},
"grace_days": {
"type": "string"
},
"invoice_number": {
"type": "string"
},
"paid_date": {
"description": "YYYY-MM-DD (default today)",
"type": "string"
},
"rate": {
"description": "Rate number (default 1.5)",
"type": "string"
},
"rate_type": {
"enum": [
"monthly_percent",
"annual_percent",
"daily_percent",
"flat"
],
"type": "string"
},
"tone": {
"enum": [
"polite",
"firm",
"final"
],
"type": "string"
}
},
"required": [
"amount",
"due_date"
],
"type": "object"
},
"type": {
"const": "http",
"type": "string"
}
},
"required": [
"type",
"method"
],
"type": "object"
},
"output": {
"properties": {
"example": {
"type": "object"
},
"type": {
"type": "string"
}
},
"required": [
"type"
],
"type": "object"
}
},
"required": [
"input"
],
"type": "object"
}