M-Pesa integration for websites: STK Push, Paybill & Till in 2026

If you sell online in Kenya, M-Pesa isn't a nice-to-have — it's usually 70–90% of your revenue. Getting the integration right is the difference between a store that converts and one that abandons at checkout.

The three M-Pesa flows on a website

• STK Push (Lipa Na M-Pesa Online) — customer taps Pay, gets a prompt, done. Best UX.
• Paybill — customer enters your business number + account manually. More friction, cheaper.
• Buy Goods (Till) — similar to Paybill, no account number. Good for single-price products.

How STK Push actually works

Behind the scenes:

• Your site calls Safaricom Daraja with the amount and the customer's phone number.
• Daraja pushes a prompt to that phone.
• Customer enters M-Pesa PIN. Safaricom confirms.
• Daraja calls your callback URL with success or failure.
• Your site updates the order and shows confirmation.

What you need before integrating

• A registered business (sole prop counts) — needed to apply for Paybill/Till.
• Paybill or Till number from Safaricom.
• Daraja developer account and app credentials.
• A live HTTPS callback URL on your website.
• A test flow — Safaricom's sandbox lets you test without moving real money.

Common pitfalls we see on Kenyan websites

• Callback URL on http:// (Safaricom requires https).
• No timeout handling — customer's prompt expires, order stuck as "processing".
• Not verifying the callback signature — anyone can spoof a success.
• Storing the M-Pesa reference in a Google Sheet instead of the database.
• No manual override for admins to mark orders paid.

What it costs

M-Pesa integration on a Kenyan e-commerce site typically adds KES 30,000 – 80,000 to the project depending on how much automation you want (auto-reconciliation, admin dashboards, refund flows). Ongoing costs from Safaricom are per-transaction and small.