Splitit Installments for OpenCart — monthly payments for US stores

Splitit Installments for OpenCart 4.x, 3.x and 2.3 adds the payment method “Pay in monthly installments with Splitit” to checkout: the buyer splits the order total into monthly payments on the bank card they already have. Payment happens on Splitit’s secure page (Hosted Form Redirect), and card data never reaches the shop. The module works with your own Splitit merchant account directly, with no middleman. The interface language is English (US).

What Splitit requires. A Splitit merchant account. The Client ID and Client Secret (API credentials) and the Terminal ID come from the Merchant Hub, and you enter them in the module settings. Terms, limits and fees are set by Splitit in your agreement with them.

What the buyer sees

Under the product price Splitit shows a “4 monthly payments of …” line with its own “learn more” pop-up. At checkout the buyer picks “Pay in monthly installments with Splitit” and presses “Continue to Splitit”. On the Splitit page the buyer chooses the number of payments, enters their card and confirms the plan, then returns to the shop on the “order placed” page. A buyer who leaves the Splitit page sees “You left the Splitit page… Nothing was charged” and a “Back to checkout” button, and the cart stays intact. If the card is declined, the buyer can try again on the same Splitit page. If the confirmation from Splitit has not arrived yet, the buyer sees a waiting page, and the order is confirmed as soon as Splitit answers.

What the admin gets

Extensions → Extensions → Payments → Splitit Installments (CatCode): the tabs “General”, “Checkout”, “Order statuses” and “Pro”. On “General” you enter the Client ID, Client Secret and Terminal ID, set the currencies of the terminal and, if needed, switch on Splitit’s sandbox. The Client Secret is stored encrypted in the database and never shown again. The “Check connection” button asks Splitit for a token and shows the answer in plain words.

The “Checkout” tab sets the method name and text per language, the payment count options on the Splitit page (for example 3, 4, 6), the preselected count, 3D Secure, the minimum and maximum order total, the geo zone and the sort order. It also switches on the message under the product price and sets the payment count it uses. The method is shown only to buyers who pay in a currency of your terminal.

An order becomes paid only after the module has asked Splitit for the plan itself (Verify Authorization): when the buyer returns, on Splitit’s call after the plan is created, or from the waiting page. The module checks the amount, currency and order number; if the plan does not match the order or a second plan was paid, the order moves to a “review” status with a note. A second click on the button does not start a second plan. The order page has a Splitit tab: the plan number, the status at Splitit, the amount, the first installment, the refunded sum, the list of payment attempts and a full-refund button.

Pro: charge later. Splitit authorizes the plan at checkout and the first installment is charged when the order reaches the status you choose (for example “Shipped”); the order page also has a “Charge the first installment” button. A separate setting names the order status at which Splitit receives the shipping status “Shipped”. Cancellations, refunds and charges made in the Merchant Hub reach the order through the webhook and a re-check of the plan; the webhook address is shown in the settings.

Partial refunds (Pro) with a Splitit refund strategy (for example FutureInstallmentsFirst), a “Check at Splitit” button on the order, a terminal per currency under one Client ID, the installment message in the cart. The payment watchdog finds open plans that Splitit never announced once an hour and settles their orders; it runs with the OpenCart 4 scheduler or from a cron URL of your hosting. The payment journal has CSV export, and the request journal lists calls to Splitit (method, path, answer code, time; no request bodies and no buyer data).

How it works, step by step

1. Install the archive for your OpenCart version and enable the module.
2. In the Splitit Merchant Hub take the Client ID, Client Secret and Terminal ID of your merchant.
3. In the module settings enter them, set the currencies of the terminal and press “Check connection”.
4. The buyer picks “Pay in monthly installments with Splitit”, goes to the Splitit page, chooses the number of payments and confirms the plan with a card.
5. The module reads the plan back from Splitit and moves the order to paid; the buyer returns to the “order placed” page.
6. With Pro, switch on charging later, partial refunds, Merchant Hub sync, the payment watchdog and the journals.

Under the hood

• Splitit Installment Plan API v3: token, Initiate, Get Plan, Verify Authorization, Refund, Update Plan; the payment page is Hosted Form Redirect, and the card is entered only on Splitit’s side.
• The Merchant Hub webhook and Splitit’s call after the plan is created are only a hint: the order changes after the module has read the plan at Splitit with your credentials.
• The message under the price is drawn by Splitit’s own script (On-Site Messaging) from their servers; its text belongs to Splitit.
• The Client Secret is stored encrypted; calls to Splitit carry an idempotency key header, so a second click does not create a duplicate.
• A plan that the buyer started but did not finish cannot be canceled through the API: if the buyer pays the old plan after a new one, the order gets a note about the double payment, and the refund is made by hand.
• Order totals, statuses and refunds: the module does not change the core and works through OpenCart events; updating keeps the settings.
• Not included: the Chargebacks API and payout reports; Merchant Hub webhooks are switched on by hand in the Merchant Hub itself (the address is in the module settings).
• Interface in English (en-gb and en-us).

How to install

1. Extensions → Installer: upload the archive for your version without renaming it (OpenCart 4: cc_splitit.ocmod.zip, 3.x: cc_splitit-oc3.ocmod.zip, 2.3: cc_splitit-oc2.ocmod.zip).
2. For 3.x and 2.3: Extensions → Modifications → Refresh.
3. Extensions → Payments → Splitit Installments (CatCode): install and open the settings.
4. Enter the Client ID, Client Secret, Terminal ID and the currencies of the terminal, press “Check connection”.
5. For Pro: paste the key or start the trial on the Pro tab.