Rental businesses live and die by billing cadence, but ERPNext core does not think in leases. Its Subscription DocType can generate repeating Sales Invoice documents, yet it has no concept of a security deposit held against a tenant, a per-day late-fee that compounds after a grace window, a mid-term rent escalation, a partial refund on early termination, or a unit that must be marked available again the moment a contract ends. Teams end up gluing these gaps together with spreadsheets, manual journal entries, and calendar reminders — which is exactly where revenue leaks, deposits get lost, and renewals slip past their notice dates.

ECOSIRE builds a proper Frappe app — its own module, installed on your bench via bench get-app and bench install-app — that models the rental lifecycle as first-class ERPNext data. The core is a Rental Contract DocType (with Rental Contract Item and Rental Schedule child tables) linked to standard Customer, Item, and Company records, so everything you build flows into native Accounts Receivable, GL, and reporting without a parallel ledger. Recurring invoices are produced by a scheduled job registered under scheduler_events in hooks.py (daily/weekly/monthly hooks), which walks active contracts, reads each one's billing frequency and proration rule, and submits Sales Invoice documents against the correct income account and cost center. Because generation runs server-side on the Frappe scheduler, it keeps working whether or not anyone is logged in.

The billing logic is enforced with doc_events server scripts and validation hooks rather than UI reminders. validate and on_submit handlers write the security-deposit entry to a dedicated deposit-liability account and track it on a tenant ledger; a late-fee routine compares invoice due_date against payment status each night and posts penalty charges once the configured grace period lapses; renewal and termination are Frappe Workflow states (Active → Renewal Due → Renewed / Terminated) with role-gated transitions, so a renewal notice, a deposit refund, and the release of the rented unit all happen as controlled, audited actions. Client scripts add the in-form UX — deposit balance display, one-click "generate next invoice," proration previews — and everything is reachable through the Frappe REST API and @frappe.whitelist() methods so your portal, payment gateway, or external site can create contracts and read tenant ledgers programmatically. Role Profiles and DocType permissions keep leasing agents, accountants, and property managers scoped to what they should see.

This is build-to-order, not a marketplace download. We start with a short scoping call to map your contract types, billing cadences, deposit and tax rules, and the ERPNext version you run (v15 or v16). You approve a written scope, we build the app in our environment, and we deliver it installed and configured on a staging copy of your site for UAT — with the full source in a Git repository you own. After sign-off we deploy to production with a rollback plan, hand over technical and user documentation, run a training session, and stay on for a post-go-live support window. Typical delivery is 2–4 weeks from confirmed scope, depending on how many contract and billing variations you need.