Guest houses, B&Bs and boutique lodges run on a stack of disconnected tools: a wall calendar or spreadsheet for room availability, a separate notebook for who has checked in, and Odoo (or nothing) for the actual invoicing. Odoo core gives you res.partner, sale.order, account.move and product.product, but it has no concept of a room as a bookable, date-ranged resource. There is no native double-booking check, no nightly rate calendar, no folio that accumulates room nights plus extras, and no housekeeping status board. You end up forcing a lodging business into a product-catalog shape it was never designed for, and reconciliation at month-end becomes guesswork.

This is a build-to-order module ECOSIRE designs and builds for your specific property. At its core is a new guest.house.room model (room number, type, floor, capacity, base rate, amenities) and a guest.house.reservation model with check-in/check-out dates, guest linked to res.partner, and a computed nights field via @api.depends. Availability is enforced with an SQL-level overlap check and a Python @api.constrains so the same room can never be reserved for overlapping dates — the double-booking problem solved at the data layer, not by staff discipline. A rate calendar model lets you set seasonal or weekend pricing that the reservation reads when computing the folio total. Reservation state moves through a documented workflow (draft → confirmed → checked_in → checked_out → invoiced / cancelled) so the calendar, housekeeping board and reporting all stay in sync.

Technically it is delivered as a proper Odoo addon: a versioned __manifest__.py, ORM models with compute and constraint methods, XML/OWL views (a Gantt-style or calendar view of room occupancy, a kanban housekeeping board driven by a cleaning_state field, and reservation forms), QWeb PDF templates for the guest folio and registration card, and automated actions for check-out-day reminders and no-show handling. Security is real: ir.model.access.csv plus record rules so front-desk staff, housekeeping and managers see only what their role allows, with multi-company record rules when you run more than one property. Confirming a reservation posts through to standard sale.order/account.move, so accounting, tax and payments stay 100% native Odoo — we extend Odoo, we do not fork it. Everything is exposed over the standard XML-RPC/JSON-RPC API so a website booking widget or channel feed can create reservations programmatically. We build against your target of Odoo 17.0, 18.0 or 19.0 and note Community vs Enterprise differences up front (e.g. the Gantt/calendar widgets and some dashboard elements behave differently on Community).

Because it is made to order, delivery runs on a defined path: a scoping call to pin down room types, rate rules, folio layout and roles; a fixed written quote; a build on a staging database; UAT with your team; then go-live with a rollback plan and a support window. Typical delivery is 2-4 weeks from confirmed scope. Pricing starts from $349 (indicative, single-company base scope); multi-property/multi-company setups, channel-manager or website-booking integrations, deeper localization (tourism tax, city tax, e-invoicing) and migration of historical reservation data increase the quoted scope.