Sends a real request to any URL you provide, attaches an Origin header, and read
Sends a real request to any URL you provide, attaches an Origin header, and reads back all six standard cross-origin permission headers the server returns. Tells you whether cross-origin requests are enabled at all, whether your specific origin is permitted, and shows every permission value exactly as the server sent it. Useful for finding why a browser is blocking a request, confirming a new deployment is configured correctly, or auditing whether a public API allows credentialed calls.
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://cors-header-checker.underscoredone.com/check
| Category | Everything else |
|---|---|
| Provider host | cors-header-checker.underscoredone.com |
| Networks | eip155:8453, solana:5eykt4UsFv8P8NJdTREpY1vzqKqZKvdp |
| Payment schemes | exact |
| Self-reported calls, 30 days | 3 from 3 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)
{
"body": {
"origin": "https://myapp.com",
"url": "https://api.github.com"
},
"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": {
"origin": {
"description": "The website address you want to test cross-origin access from, for example https://myapp.com. Defaults to https://example.com if you leave it out.",
"type": "string"
},
"url": {
"description": "The full web address of the endpoint you want to check \u2014 must start with http:// or https://.",
"type": "string"
}
},
"required": [
"url"
],
"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": {
"api_version": {
"type": "string"
},
"cors_enabled": {
"type": "boolean"
},
"error": {
"type": "string"
},
"headers": {
"additionalProperties": true,
"type": "object"
},
"origin_allowed": {
"type": "boolean"
},
"origin_tested": {
"type": "string"
},
"status": {
"type": "integer"
},
"url": {
"type": "string"
}
},
"required": [
"api_version",
"url",
"origin_tested",
"status",
"cors_enabled",
"origin_allowed",
"headers",
"error"
],
"type": "object"
},
"type": {
"type": "string"
}
},
"required": [
"type"
],
"type": "object"
}
},
"required": [
"input"
],
"type": "object"
}