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GET
/
api
/
auth
/
username-exists
Check if a username is already registered
curl --request GET \
  --url https://mcp.echozero.app/api/auth/username-exists
{
  "success": true,
  "data": {
    "exists": false
  }
}

Headers

​
x-signature
string

HMAC-SHA256 signature: HMAC-SHA256(secretKey, timestamp + METHOD + path + body). Optional -- when omitted, HMAC verification is skipped.

​
x-timestamp
string

Request timestamp in epoch milliseconds. Required when x-signature is provided. Rejected if drift exceeds 5 minutes.

Query Parameters

​
username
string
required

Username to check.

Example:

"alice_bob"

Response

Whether the username is already taken.

​
success
boolean
required
Example:

true

​
data
object
required

Endpoint-specific payload