Create a customer
Creates a customer for the merchant identified by the API key. A customer is an individual (individual) or an organization (organization); the type cannot be changed later.
external_id (your own customer reference) must be unique per merchant.
Use the returned id (starts with cus_) in other endpoints, such as starting an identity verification.
merchantApiKeymerchantTimestampmerchantNoncemerchantSignatureX-API-KEY<token>Merchant API key (starts with upk_, also accepts api-key); signing headers are also required
X-Timestamp<token>Unix timestamp in seconds, within 300 seconds of server time
X-Nonce<token>Unique per request; cannot be reused with the same credential during the timestamp validity window
X-Signature<token>Hex HMAC-SHA256 signature (either letter case) of the method, full path, timestamp, nonce and body digest
application/json- body
type*CustomerTypeCustomer type: individual or organization
"individual""organization"external_id*stringYour own customer reference, unique per merchant
length <= 64name?|Customer name (person or company), for display only
length <= 255email?|emaillength <= 255phone?|E.164 format, such as +14155550123
^\+[1-9]\d{6,14}$Customer created
application/json- response
id*stringCustomer ID (starts with cus_)
type*CustomerTypeCustomer type: individual or organization
"individual""organization"external_id*stringname*string|nullemail*string|nullphone*string|nullcreated_at*stringdate-timecurl -X POST 'https://sandbox.getupp.net/api/v1/customers' \ -H 'Content-Type: application/json' \ -d '{ "type": "individual", "external_id": "user-1001", "name": "Jane Doe", "email": "[email protected]", "phone": "+14155550123"}'{ "id": "cus_01m5e92dnjw558gdb28ajbe26b", "type": "individual", "external_id": "user-1001", "name": "Jane Doe", "email": "[email protected]", "phone": "+14155550123", "created_at": "2026-10-21T03:46:23.000000Z"}