DOCS/FLUX/Wht Filing

Single Filing

Submit a single Withholding Tax (WHT) transaction for processing and filing via the FLUX API. This endpoint supports individual WHT deductions applied to a specific payment or beneficiary.

Use this when:

You are filing WHT for a single vendor or transaction
You need immediate confirmation of the deduction
The payment is processed individually

HTTP Request

POSThttps://api.taxstreem.com/v1/flux/wht-filing/single

Request Body

The following parameters are required for this action.

Parameter	Type	Description
encryptedPayload	string	The encrypted payload of the TaxPromax credentials of the filing user.
filingId	string	Your unique ID for the filing.
beneficiaryName	string	The name of the beneficiary.
beneficiaryTin	string	The Tax Identification Number of the beneficiary.
transactionDate	string	The date of the transaction (YYYY-MM-DD).
transactionDesc	string	A description of the transaction.
transactionAmount	number	The total amount of the transaction.
rate	number	The WHT rate applied.
taxAmount	number	The calculated tax amount.
scheduleReference	string	A reference for the WHT schedule.

Encrypted Payload (In-Flight Encryption)

FLUX requires sensitive credentials to be encrypted at the application layer before transmission. This provides defense-in-depth on top of HTTPS.

The encryptedPayload field must contain a Base64-encoded AES-256-GCM encrypted JSON object.

Encryption Specification

Property	Value
Algorithm	AES-256-GCM
Key Derivation	SHA-256(sharedSecret)
IV (Nonce)	12 bytes (96-bit) random
Auth Tag	16 bytes (128-bit)
Encoding	Base64

Payload Format

The final transmitted value must be:

Base64( IV[12] || Ciphertext || AuthTag[16] )

IV is randomly generated per request
Ciphertext is encrypted JSON
AuthTag is automatically appended by GCM

Example Request

curl -X POST https://api.taxstreem.com/v1/flux/wht-filing/single \
  -H "x-api-key: txsm_test_SK489c..." \
  -H "Content-Type: application/json" \
  -d {
        "encryptedPayload": 'encrypted_string_...',
        "filingId": '123-abuiod-90',
        "month": 1,
        "year": 2024,
        "data": [
           {
               "beneficiaryName": "John Doe",
               "beneficiaryTin": "2345544-0001",
               "transactionDate": "2024-03-20",
               "transactionDesc": "Consultancy Services",
               "transactionAmount": 50000,
               "rate": 5,
               "taxAmount": 2500,
               "scheduleReference": "REF-123456"
           }
        ]
     }

Example Response

202 Accepted

{
  "status":  "accepted",
  "message":  "schedule accepted successfully",
  "data":  {
    "id":  "xaee2ddf-effvkfes",
    "created_at":  "2026-02-20T10:00:00Z"
  }
}