Create M-Pesa C2B charge (STK Push)

const options = {
  method: 'POST',
  headers: {Authorization: 'Bearer <token>', 'Content-Type': 'application/json'},
  body: JSON.stringify({
    merchantTransactionId: 'invoice_48291',
    amount: 150000,
    phoneNumber: '+254712345678',
    narration: 'Invoice 48291'
  })
};

fetch('https://api.fingopay.io/v1/mpesa/charge', 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"
  }
}

{
  "error": {
    "message": "<string>",
    "param": "<string>",
    "requestId": "<string>"
  }
}

{
  "error": {
    "message": "<string>",
    "param": "<string>",
    "requestId": "<string>"
  }
}

{
  "error": {
    "message": "<string>",
    "param": "<string>",
    "requestId": "<string>"
  }
}

{
  "error": {
    "message": "<string>",
    "param": "<string>",
    "requestId": "<string>"
  }
}

{
  "error": {
    "message": "<string>",
    "param": "<string>",
    "requestId": "<string>"
  }
}

{
  "error": {
    "message": "<string>",
    "param": "<string>",
    "requestId": "<string>"
  }
}

POST

mpesa

charge

const options = {
  method: 'POST',
  headers: {Authorization: 'Bearer <token>', 'Content-Type': 'application/json'},
  body: JSON.stringify({
    merchantTransactionId: 'invoice_48291',
    amount: 150000,
    phoneNumber: '+254712345678',
    narration: 'Invoice 48291'
  })
};

fetch('https://api.fingopay.io/v1/mpesa/charge', 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"
  }
}

{
  "error": {
    "message": "<string>",
    "param": "<string>",
    "requestId": "<string>"
  }
}

{
  "error": {
    "message": "<string>",
    "param": "<string>",
    "requestId": "<string>"
  }
}

{
  "error": {
    "message": "<string>",
    "param": "<string>",
    "requestId": "<string>"
  }
}

{
  "error": {
    "message": "<string>",
    "param": "<string>",
    "requestId": "<string>"
  }
}

{
  "error": {
    "message": "<string>",
    "param": "<string>",
    "requestId": "<string>"
  }
}

{
  "error": {
    "message": "<string>",
    "param": "<string>",
    "requestId": "<string>"
  }
}

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:

"invoice_48291"

amount

integer

required

Amount in smallest currency unit (cents). Must be whole KES (divisible by 100). Range 1,000-25,000,000 (KES 10.00-250,000.00).

Required range: 1000 <= x <= 25000000

Example:

150000

phoneNumber

string

required

Customer MSISDN in Kenyan format (+2547/2547/07 or +2541/2541/01 followed by eight digits).

Pattern: ^(?:\+254|254|0)(?:7|1)\d{8}$

Example:

"+254712345678"

narration

string

Optional customer-facing narration. Maximum 140 characters.

Maximum string length: 140

Example:

"Invoice 48291"

webhookUrl

string<uri>

Override webhook destination for this charge.

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.

Hide child attributes

metadata.{key}

Maximum string length: 500

shortcode

string

[Enterprise] Optional collections shortcode to route the charge via your dedicated shortcode.

Example:

"123456"

subMerchantId

string

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

Example:

"SM-NAIROBI-001"

customDisplayName

string

Optional custom display name shown to customer (alphanumeric and spaces only, max 40 chars).

Maximum string length: 40

Pattern: ^[a-zA-Z0-9 ]+$

Example:

"ACME Store"

Response

Accepted — final result will be delivered via webhook.

status

string

required

Example:

"success"

message

string

required

Example:

"Transaction initiated successfully"

data

object

required

Hide child attributes

data.merchantTransactionId

string

required

Example:

"mtx_123"

data.transactionId

string

required

Example:

"txn_01j7b6f9p5y9h"

Fingo Pay API reference

Request M-Pesa reversal

⌘I

Overview

Payments

Payouts

Verification

Accounts

Transactions

Models

Create M-Pesa C2B charge (STK Push)

Authorizations

Headers

Body

Response