Launching 2026

Transactional notifications
for developers

Email, SMS and push notifications in one API. Built for Java and Spring Boot developers. Pay only for what you send.

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Send your first notification in under 2 minutes

// Spring Boot — one dependency, zero config
StackSendClient client = new StackSendClient("sk_live_your_api_key");

client.email()
    .to("user@example.com")
    .subject("Your order was confirmed")
    .template("order-confirmation")
    .variable("orderId", orderId)
    .send();

// Same client for SMS and push — one API key, all channels

What's included

✉️

Transactional email

REST API and Spring Boot SDK. Async delivery with Kafka, retries, dead-letter queue and full delivery tracking.

💬

SMS

Send SMS to any country. Usage-based pricing with no monthly minimums. Built-in delivery receipts.

🔔

Push notifications

iOS and Android push via a single API call. No SDK to maintain on the client side.

📊

Dashboard and logs

Every notification logged. Filter by status, channel, date and recipient. Export for compliance.

🔗

Webhooks

Get notified on delivered, bounced, opened and failed events. Retry logic included.

🛡️

Production-grade reliability

JWT auth, DKIM/SPF managed for you, rate limiting, bounce handling and a public status page.

Simple, usage-based pricing

Pay for what you send. No tiers, no surprises, no lock-in.

Channel Price Unit
✉️ Email $0.50 per 1,000 emails
💬 SMS $0.05 per message
🔔 Push $0.20 per 1,000 notifications
ℹ️ $5/month platform fee for API access, dashboard and support. No charge when inactive.

Built on a stack you trust

Production-grade infrastructure for teams that can't afford downtime.

Java 21 Spring Boot 3 Apache Kafka PostgreSQL Docker Kubernetes Prometheus Grafana AWS SES JWT / OIDC Flyway Testcontainers