Merchants who want to sell higher-ticket items increasingly need to offer "pay over time" — but out of the box, Odoo checkout is single-payment. You can already save payment tokens with a gateway that supports it, but there is no native concept of an installment schedule: no way to define "split this €1,200 order into 4 monthly charges," no scheduler to auto-charge the saved token on the due date, no per-installment invoicing, and no dunning when a charge fails. Bolting a third-party BNPL provider (Klarna, Tabby, Afterpay) on top hands the customer relationship and a 3–6% fee to someone else. If you want to keep the financing in-house — your margins, your cash flow, your customer — Odoo native runs out of road and you end up tracking schedules in spreadsheets.

ECOSIRE builds the missing layer as a proper Odoo module for your exact version. We add an installment.plan model (defining N installments, cadence, optional down-payment, and per-installment fees) and an installment.schedule.line model holding each due date, amount, state, and its link to the generated account.move and payment transaction. Amounts are compute fields with @api.depends so a change to the plan or order total re-derives the whole schedule and always reconciles back to the order value. On the storefront we extend the sale/payment checkout flow (controllers + QWeb/OWL templates) so the buyer picks a plan, sees the exact schedule and fee breakdown, and authorizes tokenization — reusing Odoo's existing payment.token so we never touch raw PAN data.

The engine is an ir.cron scheduled job that each day picks up due installment.schedule.line records and charges the saved token through the gateway's server-to-server flow (_send_payment_request on the payment.transaction), then posts and reconciles the corresponding invoice. Failed charges enter a configurable dunning ladder — retry after N days, escalate email reminders via Odoo templates and automated actions, and flag the account after the final attempt. Customers get a self-service portal view (extending /my) listing upcoming and paid installments, receipts, and the ability to settle early. Access is locked down with ir.model.access.csv plus record rules so a portal user only ever sees their own schedule, and every state transition is written to the chatter for audit. Admins get QWeb reports for the amortization schedule and an operations list of at-risk plans. Everything is also reachable over XML-RPC/JSON-RPC for integration with external CRM or collections tooling.

Because this is built to your requirements, we confirm the details up front: which gateway(s) you tokenize with, Community vs Enterprise (Enterprise unlocks tighter accounting automation and some payment-provider connectors; on Community we implement the equivalent flows against your gateway's API), your tax and revenue-recognition rules for split payments, and your dunning policy. We deliver on Odoo 17.0, 18.0, or 19.0 to match your instance. Typical delivery is 2–4 weeks from confirmed scope — you receive installable source code, deployment on your staging server for UAT, and a support window after go-live. It starts with a short scoping call, not a checkout button.