STK Push Explained: Why Your Customers Never Have to Type Again

When a customer checks out on your Greatr store, their phone buzzes with a payment prompt. Here is how that magic works.

AH

Amina Hassan

Jan 22, 2026

·4 min read
M-PesaPaymentsHow-To
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When a customer checks out on a Greatr store, their phone vibrates with a payment prompt. They enter their PIN, tap OK, and the payment is confirmed — instantly.

What Is STK Push?

STK stands for SIM Toolkit — the technology in every Safaricom SIM card that allows apps to push prompts directly to your phone. Greatr uses it to skip the entire manual Pay Bill flow.

What Happens Step by Step

  1. 1Customer selects Pay with M-Pesa and enters their phone number
  2. 2Greatr sends an STK Push request to Safaricom with the exact amount
  3. 3Safaricom pushes a payment prompt to the customer's phone within seconds
  4. 4Customer enters their M-Pesa PIN and taps OK
  5. 5Order is automatically marked as Paid in your dashboard

"Before Greatr, I wasted an hour every day confirming payments. Now I wake up and just see a list of confirmed orders."

What About Failed Payments?

Greatr automatically holds the order as Pending and prompts the customer to retry. The order is never confirmed unless payment succeeds. Zero risk of shipping unpaid orders.

AH

Written by Amina Hassan

Amina Hassan is co-founder and CTO of Greatr. She previously built payments infrastructure at Cellulant.

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