Validate an ISBN-10 (mod-11) or ISBN-13 (1,3-weight mod-10) checksum
Validate an ISBN-10 (mod-11) or ISBN-13 (1,3-weight mod-10) checksum.
Answeringour last check, 2026-10-18
1 of 1checks answered this week
41 msmedian answer time
$0.005listed price per call
$0.005price 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
POST https://hcrb.in/v1/tools/isbn-check/call
| Category | Everything else |
|---|---|
| Provider host | hcrb.in |
| 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
| Day | Result | HTTP | Asked | Time |
|---|---|---|---|---|
| 2026-10-18 | valid payment request | 402 | $0.005 | 41 ms |
Example input (from the provider)
{
"body": {
"input": {
"isbn": "978-0-306-40615-7"
}
},
"bodyType": "json",
"method": "POST",
"type": "http"
}
Promised output schema (from the provider)
{
"$schema": "https://json-schema.org/draft/2020-12/schema",
"properties": {
"input": {
"additionalProperties": false,
"properties": {
"body": {
"additionalProperties": false,
"properties": {
"input": {
"properties": {
"isbn": {
"description": "ISBN-10 or ISBN-13; dashes/spaces allowed.",
"type": "string"
}
},
"required": [
"isbn"
],
"type": "object"
}
},
"required": [
"input"
],
"type": "object"
},
"bodyType": {
"enum": [
"json",
"form-data",
"text"
],
"type": "string"
},
"method": {
"enum": [
"POST",
"PUT",
"PATCH"
],
"type": "string"
},
"type": {
"const": "http",
"type": "string"
}
},
"required": [
"type",
"method",
"bodyType",
"body"
],
"type": "object"
},
"output": {
"properties": {
"example": {
"properties": {
"country": {
"type": "string"
},
"normalized": {
"type": "string"
},
"reason": {
"type": "string"
},
"scope": {
"type": "string"
},
"tool": {
"type": "string"
},
"valid": {
"type": "boolean"
}
},
"required": [
"valid",
"reason"
],
"type": "object"
},
"type": {
"type": "string"
}
},
"required": [
"type"
],
"type": "object"
}
},
"required": [
"input"
],
"type": "object"
}