Open Source SMS gateway
An open-source SMS messaging gateway for teams that want control, reliability, and visibility—without “black-box” vendor lock-in.
What is Sendium
Sendium is an open-source, headless SMS gateway engineered for high-throughput delivery. Designed to sit seamlessly between your internal applications (CRMs, websites, IoT platforms) and your SMS connectivity (carriers, SMPP providers), it puts you firmly in control of your messaging infrastructure.
It lets you run your own gateway layer, which gives you the power to manage connections, adjust routing on the fly, prioritize traffic, and dictate fail-over rules. Built for maximum scalability and flexibility, Sendium eliminates vendor lock-in entirely and can be easily deployed across any on-premise or cloud environment.
How it works
Your application sends a message to Sendium over HTTP
Sendium applies routing rules (country/prefix, sender ID, message type, priority, etc.)
Sendium delivers through one or more SMPP connections to upstream providers
Delivery receipts (DLRs) come back asynchronously
Sendium normalizes the status and forwards it back to your systems (HTTP callbacks or SMPP reports)
Core Capabilities
SMPP Server & Client
(full bind support)
- Accept inbound binds from your applications or downstream customers (TX/RX/TRX)
- Maintain persistent binds to upstream carriers/aggregators for outbound delivery
Granular TPS control
(rate limiting)
- Set Transactions-Per-Second limits per upstream connection
- Protect your links and stay within SLAs
Advanced routing
engine
- Route by destination prefix, sender ID, or message content
- Automatic failover when a primary connection drops
Protocol translation
(HTTP ↔ SMPP)
- HTTP in → SMPP out for modern app stacks
- SMPP MO in → HTTP webhooks out for inbound SMS flows
Real-time DLR
management
- Delivery isn’t “done” until it’s verified
- Normalize DLR status and propagate it back to your originating systems
Modern, headless architecture
- Designed as a practical Kannel replacement (modern Java/Quarkus stack)
- Container-native and fast to deploy (Docker-friendly)
SMPP over TLS
- Secure connectivity
- Support SMPP TLS/SSL configuration
Metrics visibility
- Exposed Prometheus-compatible metrics at /q/metrics.
- Grafana-ready observability
Messages Priority
- Support priority-aware queues, honoring each message's priority attribute.
- OTPs always jump the line
Typical use cases
Offering an alternative to Kannel
If your gateway is hard to maintain, hard to staff for, and painful to extend — Sendium gives you the same core gateway functions in a modern, container-friendly stack.
Aggregators & hubs
Route traffic from multiple customers to multiple upstream carriers with clear rules (e.g., “UK → Carrier A, FR → Carrier B”), plus failover.
Enterprise notification systems (OTPs, alerts, priorities)
Run Sendium on-prem or in your private cloud. Keep control of routing, logs, and security posture — while prioritizing critical traffic (e.g. OTPs) over non-critical messaging.
IoT / M2M signaling
Translate API commands from your IoT platform into SMS signals when data coverage is unreliable.
What's Next
Resilience & compatibility
- Kannel configuration parity (easy migration mindset)
- Optional SQL-backed DLR storage, similar to Kannel-style persistent DLR handling
Advanced routing & intelligence
- Automatic fallback/retry paths
- Health-based rerouting (low deliverability detection)
- Load balancing across providers
- Billing-aware routing
MNP-aware routing
- Fair routing
- HLR lookup
Scale & integrations
- Apache Kafka integration for massive async throughput
- Foundations for multichannel routing (e.g., WhatsApp, RCS, Viber)