India GST POS Billing & E-Invoice for ERPNext

ECOSIRE builds a dedicated Frappe app — its own module, DocTypes and hooks — that closes those gaps directly inside the ERPNext POS. We add place-of-supply resolution as a server-side function wired through hooks.py doc events (validate / before_submit on POS Invoice and Sales Invoice) that compares the company GSTIN state code against the customer's billing/shipping GSTIN or state, then deterministically applies CGST+SGST for intra-state and IGST for inter-state — so the cashier never chooses. HSN/SAC codes are mapped from the Item master and validated against tax rate, with a client script that blocks submission when an HSN code is missing or its rate disagrees with the applied Item Tax Template. A whitelisted server method calls the IRP/e-invoice API to fetch the IRN and signed QR, stamps them onto the invoice, and renders the QR on the thermal/A4 print format; failures are logged to a custom E-Invoice Log DocType with retry via a scheduler event so a network blip never blocks the queue.

Composition-scheme billing is handled as a first-class mode: for a registered composition dealer the app suppresses tax lines on the customer-facing bill, prints the mandatory "composition taxable person, not eligible to collect tax" declaration, and keeps the internal turnover accounting intact for the quarterly CMP-08 view. Role profiles and permissions are set so counter staff can bill and generate IRNs but cannot edit tax rules, HSN maps or GSTIN configuration; those stay with the accounts/admin role. Everything is exposed cleanly over the Frappe REST API and whitelisted methods so your POS terminals, kitchen display, or a headless front-end can drive it, and the whole app is packaged as a versioned Frappe app compatible with ERPNext/Frappe v15 and v16.

Because this is build-to-order, nothing ships until we agree on scope. We start with a short scoping call, confirm your GST registration type, turnover/e-invoicing applicability, IRP credentials path, print formats and terminal setup in a written scope, then build against that. Typical delivery is 2-4 weeks from confirmed scope. You get the installable source for your version, a UAT pass on a staging bench with a rollback plan, install and configuration on your instance, documentation, a training session for counter and accounts staff, a post-go-live support window, and the git repository handed over so you own what we built.