The systems you already pay for can almost always be made to talk to each other. An integration is code that moves data between two systems when something happens: an order is paid, a customer signs up, a parcel ships. Most are one-way, pushing data from one system into another, and those are the straightforward ones. A two-way sync, where both sides change the same records, takes far more care.
What can an integration do for your business?
- A paid order becomes an invoice in your accounting package, with the payment fee recorded separately. Yoco does part of this out of the box.
- A paid order books its own courier and gets its waybill, through The Courier Guy’s API.
- The customer gets their order or booking confirmation on WhatsApp, sent by your system.
- One loan application goes out to several lenders’ APIs at once, which is what the loan origination API I built does.
- Your business records live in a database every system can read, rather than locked inside one product. WeCoza works that way.
How does an integration work?
It starts with a trigger. With a webhook, the other system tells yours the moment something happens. With polling, your system asks on a timer. Webhooks are faster and kinder to the other side’s rate limits, so use them wherever they are offered.
Every incoming message gets checked. Payment gateways sign their webhooks so that you can prove a message came from them before you act on it. Paystack and Yoco both document how.
Every step has to be safe to repeat. Gateways retry when a delivery fails, Paystack for up to 72 hours, so the same event can arrive twice. Key each write on the event or order reference, and a repeat changes nothing.
Data gets mapped between the two sides. The same customer has different field names in each system, and even formats shift: The Courier Guy takes a province as “Gauteng” and sends it back as “GP”.
And everything gets logged. When the other side changes its API without telling you, the log shows which call broke and why, instead of a customer telling you a week later.
What makes an integration hard?
The other system’s documentation matters most. A documented API with a sandbox to test against is quick to work with. An undocumented one means learning its behaviour by trial, and you should hear about that before the work starts.
Two-way syncs need a rule for conflicts. When a price changes in your store and in your stock system on the same afternoon, something has to decide which one wins.
Old systems without an API need a way in: a file export on a schedule, read access to the database, or occasionally working through the screens.
The rest only shows up once you are live. Refunds, partial payments, cancelled orders and a customer who pays twice all need handling, and testing has to go looking for them.
What does it take to keep an integration running?
APIs change. In 2026 The Courier Guy moved its plugin to a new API address, after retiring its older keys in 2023. Ozow now marks its older Payments API as deprecated. Credentials expire too, and vendors switch off endpoints.
Someone has to own each integration after launch: alerts that name the system and the record that failed, and time set aside to adjust when a vendor changes something. Budget as well for the vendors’ own fees, such as a gateway’s charge per payment or Meta’s per-message rate on WhatsApp.
Sources
- The Courier Guy, Shipping for WooCommerce plugin changelog, for the API address change and the retired keys
- Ozow, Developer hub
- Paystack, Webhooks
- The estimate above is drawn from indicative prices published by Syniq Solutions, read on 19 October 2026