Most French merchants running Odoo eCommerce already hold a Monetico Paiement contract with Crédit Mutuel, CIC, or OneyBank — but Odoo core ships no acquirer for it. Out of the box, payment and website_sale give you a generic payment.provider framework and adapters for a handful of international gateways, none of which speak the Monetico seal (MAC) protocol. Teams end up either redirecting customers off-site to a hosted page that never reconciles cleanly back to the sale order, or hand-patching a fragile bridge that trusts the browser return and silently double-confirms orders on a refresh. Neither is acceptable when the bank's server-to-server notification (the retour) is the only trustworthy source of payment truth.

We build a dedicated Monetico acquirer as a proper Odoo module. It registers a new payment.provider record type carrying your TPE (terminal number), société code, and MAC HMAC key (the key is stored encrypted, never rendered in views or logs). At checkout, the provider generates the Monetico payment form with a HMAC-SHA1 seal computed over the canonically-ordered field string exactly per the Monetico Paiement specification, so the bank accepts the request first time. Amounts are formatted to EUR cents with strict validation — no floating-point drift, no locale ambiguity — before they enter the sealed string. The customer is redirected to the Monetico hosted payment page, completes 3-D Secure inline, and returns to your site.

The critical work is on the return path. A controller handles the server-to-server retour URL, recomputes the MAC over the received fields, and rejects any notification whose signature does not verify — this, not the browser redirect, is what moves the payment.transaction to done and confirms the sale order. Browser-return handling is fully idempotent: a refresh, a back-button, or a duplicate hit resolves to the existing transaction state and can never create a second confirmation or a double invoice. Every signed request and verified response is written to an audit log so disputed payments can be reconstructed field-by-field. On top of the base flow we build the revenue features Monetico offers: installment / split plans (paiement fractionné) configured against the order, deferred capture, and refunds issued straight from the order or invoice through the Monetico recredit (remboursement) API, with the credit reconciled back onto account.payment. A preproduction/production endpoint toggle lets you certify on the bank's test platform before going live.

Because this is made to order, delivery is not instant. After a short scoping call we confirm exactly which capabilities you need (single vs. multi-company, installment plans, deferred capture, marketplace splits), certify against your Monetico preproduction credentials, run UAT on a staging copy of your database, then deploy to production with a rollback plan. Typical delivery is 2–4 weeks from confirmed scope. The module targets Odoo 17.0, 18.0, and 19.0 and works on Community or Enterprise. Pricing starts from $249 (indicative, single-company base scope); multi-company acquirers, additional installment/marketplace plan logic, and deeper accounting-reconciliation or data-migration work increase the quoted scope, which we fix in a written quotation after the scoping call.