Setting Up STK Push Checkout on Your POS

STK Push is the fastest way to take M-Pesa at a Kenyan counter: the till sends the payment prompt to the customer's phone, they confirm the amount and enter their PIN, and the sale closes itself. No typing till numbers into a phone, no 'confirm with M-Pesa' back and forth.

This guide covers how STK checkout works, what the cashier sees at every step, and how to test it safely before a real queue relies on it.

1. Where STK Push Comes From

STK Push runs on the same KopoKopo gateway you connected for payments — the same credentials, the same till number. At checkout, M-Pesa appears as a tender option marked 'Your till STK.' Tap it, enter the customer's number, send the prompt, and the sale completes on confirmation.

2. The Flow, Step by Step

• Ring up the sale — the cart shows the total.
• Tap M-Pesa — the tender tile marked 'Your till STK.'
• Enter the customer's number — area code and number; the till checks it's a valid Kenyan mobile before sending.
• Send the prompt — the till shows Sending, then Waiting on the number.
• The customer confirms — amount and PIN on their phone; the till shows Confirmed and completes the sale: receipt, stock, shift record.

3. What Each Till State Means

The states are the whole story: Ready (enter the number, send the prompt), Sending (the prompt is on its way), Waiting (the customer has it — you can send again if needed), Confirmed (green, with the locked amount and a reference — completing the sale), and Failed (red, with a retry).

4. The Two M-Pesa Modes

STK Push is the till-initiated mode. The other is the customer-initiated one: the customer pays the Buy Goods till number directly while the till listens — the cashier can keep adding items, and the sale completes when Kopo Kopo confirms. Both are built into the same M-Pesa tender.

5. Testing Without Risk

• Ring up a KES 10 sale — a nominal item or a price override.
• Pay it with your own number — confirm the prompt on your own phone.
• Watch the till go Sending → Waiting → Confirmed, and the sale close itself.
• Check the shift record: KES 10 in M-Pesa, matched, no manual entry.

If the test fails, it's almost always one of three things: the number format, the gateway not being ACTIVE, or the environment not matching where the money actually lands — the same checks as the connection guide.

6. What Can Go Wrong (and the Fix)

• Wrong number — the till rejects it before sending.
• Prompt failed — retry; usually a declined or expired prompt.
• Customer takes too long — send again from the Waiting state.
• Till offline — STK needs a connection, and the send is blocked until it's back.
• Keeps failing — check gateway ACTIVE and the environment.

Read next:

• Kopo Kopo Integration for POS Systems: The Complete GuideThe pillar guide — STK Push in the context of the whole integration.→
• How to Connect Kopo Kopo to Your POS SystemGet the gateway ACTIVE first — then STK just works.→
• Kopo Kopo Buy Goods vs. Till Number vs. PaybillWhen STK, and when the till-direct mode, for your shop.→
• Kopo Kopo API Webhooks Explained for Non-DevelopersThe signed confirmation that closes the sale — explained plainly.→
• Kiosk.ke's Kopo Kopo IntegrationThe deep-dive on how Kiosk runs both M-Pesa modes.→