Request Format

All requests to the InterPay™ gateway are sent over HTTPS on port 1443. Both GET and POST methods are supported.

Tag/Value Format

Requests are constructed by concatenating fields and values, separated by ampersands:

TERMID=MYTERM01&PASS=mypass&TYPE=W&ACTION=StartSession&AMT=125.00&[email protected]

Field values must be URL-encoded to allow special characters. If an ampersand (&) is needed within a field value, send it as a double ampersand (&&) to avoid confusion with field separators.

For structured data, fields can represent groups using nested brackets:

&PYMTS=[DATE=20260401&AMT=125.00][DATE=20260501&AMT=135.00]

JSON Format

Requests can be submitted as JSON in the body of a POST request with Content-Type: application/json:

{
  "TERMID": "MYTERM01",
  "PASS": "mypass",
  "TYPE": "W",
  "ACTION": "StartSession",
  "AMT": "125.00",
  "CUSTEMAIL": "[email protected]"
}

Structured data uses arrays of objects:

{
  "PYMTS": [
    { "DATE": "20260401", "AMT": "125.00" },
    { "DATE": "20260501", "AMT": "135.00" }
  ]
}

GET vs POST

Method	How to send data	When to use
GET	Fields in the query string	Quick browser-based testing
POST	Fields in the query string or the request body (tag/value or JSON)	Production integrations

Both methods produce the same result. GET is useful for early testing — you can paste a request URL into a browser and see the response directly.

Response Format

The gateway matches the response format to your request:

You send	You get back	Content-Type
Tag/value	Tag/value	`text/plain`
JSON body	JSON	`application/json`
Tag/value with `JSON=Y`	JSON	`application/json`

To force a JSON response regardless of request format, include JSON=Y as a parameter:

TERMID=MYTERM01&PASS=mypass&TYPE=W&ACTION=StartSession&AMT=125.00&JSON=Y

Standard Response Envelope

Every gateway response includes these fields:

Field	Description
`CODE`	Result code. `0000` means success. Any other value indicates an error or decline.
`TEXT`	Human-readable result message (e.g. `SUCCESS`, `APPROVED`, `DECLINED TEST`, `MISSING CUST EMAIL`).
`DATE`	Date the response was generated (`YYYY-MM-DD`).
`TIME`	Time the response was generated (`HH:MM:SS`).
`DUR`	Request processing duration in seconds (e.g. `0.412`).

Additional fields vary by request type and are documented in each method's Parameter Descriptions page.

Tag/value response example:

TEXT=SUCCESS&CODE=0000&SECUREID=1ef3a4c0-1234-6abc-b6f0-0607737344b4&URL=https://svra.interpaypos.com:1443/api/HOSTPYMT/pay/?SecureID=1ef3a4c0-1234-6abc-b6f0-0607737344b4&DATE=20260412&TIME=14:23:01&DUR=0.412

JSON response example:

{
  "CODE": "0000",
  "TEXT": "SUCCESS",
  "SECUREID": "1ef3a4c0-1234-6abc-b6f0-0607737344b4",
  "URL": "https://svra.interpaypos.com:1443/api/HOSTPYMT/pay/?SecureID=1ef3a4c0-1234-6abc-b6f0-0607737344b4",
  "DATE": "2026-04-12",
  "TIME": "14:23:01",
  "DUR": "0.412"
}

Approved-Transaction Fields

The following fields are added automatically when a financial transaction is approved:

Field	When returned	Description
`AUTH`	Approved transactions	Authorization number from the card network
`GATEREF`	Approved financial transactions (Type `E`)	Gateway reference for settlement and reconciliation. Store this alongside your own transaction record.
`TOKEN`	When card data was processed	Permanent token for reusing this card on future transactions
`HASH`	When card data was processed	Hash of the card data for deduplication or fraud checks

These fields will not appear on declines, validation errors, or non-financial calls.

HTTP Status Codes

The gateway always returns HTTP 200 OK, including for declines and errors. Always check the CODE field in the response body to determine the result — do not rely on the HTTP status code.

Error Handling

Errors are returned in the same format as the request with a non-0000 CODE and a descriptive TEXT message.

Example error response:

{
  "CODE": "9014",
  "TEXT": "MISSING CUST EMAIL",
  "DATE": "20260412",
  "TIME": "14:25:33",
  "DUR": "0.003"
}

Check CODE on every response. A value of 0000 means the request succeeded. Any 9xxx code indicates a validation or gateway error. Any 0xxx code (other than 0000) indicates a decline from the card network.

If a gateway server does not respond or returns a 99xx error code, retry the request on the other gateway server. See [Production] for server URLs.

XML Format

XML responses are also supported by including XML=Y in the request. The response will be returned with Content-Type text/xml. JSON is recommended for new integrations.