Indian SMBs running ERPNext quickly hit a wall on SMS. ERPNext ships with a generic SMS Settings screen that pushes messages to an HTTP gateway, but it has no concept of India's TRAI/DLT regime — no principal-entity or template registration, no sender-ID (header) mapping, no distinction between transactional and promotional routes, and no built-in OTP send-and-verify workflow. The result is silently dropped messages, non-compliant content templates, and OTP logic bolted on with fragile custom scripts. MSG91 is the gateway most Indian teams standardize on, but wiring it into ERPNext properly — with DLT variables mapped to your documents and delivery status flowing back — is exactly where the native tooling runs out of road.

ECOSIRE builds a proper Frappe application (its own installable app with a versioned hooks.py, module, and DocTypes) that turns MSG91 into a first-class ERPNext messaging layer. At the core is a MSG91 Settings single DocType that holds your Auth Key, base route, and defaults, and a DLT Template DocType that stores each approved DLT template ID, its registered sender ID/header, route (transactional vs promotional), and the ordered variable list. Outbound sends resolve through MSG91's flow/template API so the message that leaves your system always carries a DLT-registered template — the compliant path, not a raw text blob. All traffic and every callback is persisted to an SMS Log DocType (recipient, template, MSG91 request ID, route, status, timestamps) so you have an auditable trail per document and per campaign.

The connection to your business documents is done the Frappe-native way. We register hooks.py doc events (for example on_submit on Sales Invoice, Delivery Note, or Payment Entry) that call whitelisted server methods to fire the right DLT template with the correct field mappings — no hard-coding, the trigger-to-template map is data in a DocType you control. OTP is delivered as a reusable whitelisted method pair (send_otp / verify_otp) exposed over the Frappe REST API and callable from portal pages, custom app flows, or client scripts, with configurable OTP length, expiry, retry throttling, and hashed storage. Delivery-report reconciliation runs two ways: a public webhook endpoint that ingests MSG91 DLR callbacks, plus a scheduler_events job that polls for any pending statuses so the SMS Log never goes stale. Everything is wrapped in Frappe permissions and role profiles so, for example, only a "SMS Manager" role can edit templates or read the Auth Key, while agents can only send.

Because this is build-to-order, nothing ships until we agree on scope. We start with a short scoping call to confirm your MSG91 account setup, your registered DLT templates and sender IDs, which ERPNext documents should trigger which messages, and your OTP use cases. We then build against your requirements, targeting Frappe/ERPNext v15 and v16, validate on a staging bench through UAT, and only then install on production with a rollback plan. Typical delivery is one working week from confirmed scope, and you receive the full git repository so the work is yours to maintain, extend, or hand to another team.