ERPNext ships an SMS Settings DocType, but it assumes one gateway with a single GET/POST URL and hard-coded parameter names. The moment you need failover between providers, region-specific routing (an Indian MSG91 route for domestic traffic and a Twilio route for international), DLT-registered template and sender-ID enforcement, or genuine delivery receipts written back to the sending document, that native config runs out of road. Teams end up hard-coding a second gateway into a custom script, lose every message when the primary provider throttles, and have no audit trail of what actually got delivered versus what silently failed at the carrier.

The Multi-Gateway SMS Hub is a proper Frappe app (its own module, installed via bench get-app and bench install-app) that introduces a pluggable gateway abstraction. Each provider — MSG91, Twilio, Vonage, Infobip, Sinch, and any regional aggregator you use — is a configured SMS Gateway record implementing a common send interface, with credentials, base URL, auth style, throughput limits and a priority/weight for routing and failover. A central SMS Message DocType is the single log for every outbound and inbound message, carrying provider message-id, status, cost, segment count and the linked source document. Routing rules select a gateway by country prefix, message type (transactional vs promotional) or sender ID, and fall through to the next-priority gateway on a hard failure.

Sending is wired into ERPNext through hooks.py document events and scheduler events, not one-off buttons. A doc_events handler fires SMS on state transitions you choose — Sales Order on_submit, Delivery Note dispatch, Payment Entry receipt — using a SMS Template DocType with Jinja placeholders bound to the source doc, and enforcing your DLT/sender-ID mapping so non-compliant sends are blocked before they hit the carrier. Delivery Receipts (DLR) arrive on a whitelisted webhook endpoint (a @frappe.whitelist(allow_guest=True) method with signature verification), which updates the matching SMS Message status and timestamps. Inbound (two-way) SMS lands on the same webhook layer and is routed by keyword or virtual number to create a ToDo, Communication, or a lead/ticket against the right party. Bulk campaigns run as a queued, rate-limited background job over a segmented recipient list (Report/Query filters or Contact tags), respecting per-gateway throughput and quiet-hours. Roles and permissions are handled with a dedicated role profile so marketers can send campaigns without touching gateway credentials, and every send is exposed over the standard Frappe REST API and whitelisted methods for your other systems.

Because this is build-to-order, we start from your actual gateways, DLT/sender-ID registrations, the exact DocTypes and events that should trigger messages, and your compliance constraints — then build, test on a staging bench, and hand over the running app. Typical delivery is one working week from confirmed scope. You receive the full source and git repository, so nothing is locked behind a marketplace subscription; ECOSIRE installs it on your v15 or v16 site, trains your team, and supports it through go-live.