Skip to main content
POST
/
v1
/
mpesa
/
b2b
const options = {
  method: 'POST',
  headers: {Authorization: 'Bearer <token>', 'Content-Type': 'application/json'},
  body: JSON.stringify({
    merchantTransactionId: 'b2b_4521',
    amount: 2500000,
    accountNumber: '1234567',
    accountNumberType: 'paybill',
    beneficiary: 'INV-12345',
    narration: 'Restock float'
  })
};

fetch('https://api.fingopay.io/v1/mpesa/b2b', options)
  .then(res => res.json())
  .then(res => console.log(res))
  .catch(err => console.error(err));
{
  "status": "success",
  "message": "Transaction initiated successfully",
  "data": {
    "merchantTransactionId": "mtx_123",
    "transactionId": "txn_01j7b6f9p5y9h"
  }
}

Authorizations

​
Authorization
string
header
required

Use your API key as a Bearer token. Example: Authorization: Bearer sk_live_...

Headers

​
Idempotency-Key
string<uuid>

Unique key to safely retry POST without duplicates. Required in live environment.

Body

application/json
​
merchantTransactionId
string
required

Merchant-side reference used for reconciliation. Accepts 1-64 characters (letters, numbers, dot, underscore, or hyphen).

Required string length: 1 - 64
Pattern: ^[A-Za-z0-9._-]{1,64}$
Example:

"b2b_4521"

​
amount
integer
required

Amount in smallest currency unit (cents). Range 1-15,000,000 (KES 0.01-150,000.00).

Required range: 1 <= x <= 15000000
Example:

2500000

​
accountNumber
string
required

Destination till or paybill number.

Example:

"1234567"

​
accountNumberType
enum<string>
required

Destination M-Pesa account type.

Available options:
till,
paybill
Example:

"paybill"

​
beneficiary
string

Account reference required when accountNumberType is paybill. Can be blank for till transfers.

Example:

"INV-12345"

​
narration
string

Optional narration displayed to the beneficiary. Maximum 140 characters.

Maximum string length: 140
Example:

"Restock float"

​
webhookUrl
string<uri>

Override webhook destination for this transfer.

Example:

"https://merchant.example/webhooks/fingo"

​
metadata
object

Custom metadata key-value pairs. Up to 20 entries. Keys 1-64 characters (letters, numbers, dot, underscore, or hyphen). Values are strings, except reserved key subMerchantDetails which accepts an object.

​
shortcode
string

[Enterprise] Optional shortcode to use for this B2B transfer.

Example:

"600123"

​
subMerchantId
string

[Enterprise] Optional internal sub-merchant identifier configured under your organization.

Example:

"SM-NAIROBI-001"

Response

Accepted — final result will be delivered via webhook.

​
status
string
required
Example:

"success"

​
message
string
required
Example:

"Transaction initiated successfully"

​
data
object
required