This document defines the shared response envelope used across all Nelnet Payment Services (NPS) APIs.
All NPS APIs return HTTP 200 for both success and failure outcomes. Always branch logic on responseCode. Never use responseMessage for conditional logic.
| Field | Present | Purpose |
|---|---|---|
responseCode | Yes | Reserved — source of truth for outcome |
responseMessage | Yes | Reserved — informational only |
responseDetails | No | Reserved — per-error detail, multiple errors only |
<API-specific fields> | No | Defined by each API endpoint |
responseMessage is informational only. Its format is not guaranteed and should not be parsed programmatically. Do not build application logic that depends on its content.
responseCode always begins with a prefix that indicates the category of the outcome.
| Prefix | Category | Description |
|---|---|---|
A | Success | Request completed successfully |
E | Error | Input validation or processing error occurred |
Each API defines its own set of response codes within these prefix categories. Refer to the individual API reference for the full list of valid responseCode values.
{
"responseCode": "A100",
"responseMessage": "Approved"
}Additional fields vary by endpoint. Refer to the individual API reference for the full response schema.
When only one error occurs, it is represented at the top level. responseDetails is omitted.
{
"responseCode": "E410",
"responseMessage": "Invalid length for field 'accountNumber'"
}When multiple errors occur, the first error populates the top-level responseCode and responseMessage. Additional errors are listed in responseDetails.
{
"responseCode": "E410",
"responseMessage": "Invalid length for field 'accountNumber'",
"responseDetails": [
{ "responseCode": "E409", "responseMessage": "Invalid format for field 'amount'" },
{ "responseCode": "E405", "responseMessage": "TransactionType is required" }
]
}responseDetails is never an empty array. If there is only one error, responseDetails is omitted entirely and the error is represented at the top level.