IPAWS Feed and Pub/Sub Integration Overview

This document distills guidance received from the IPAWS Program Management Office and outlines concrete ways our NOAA Alerts System can leverage the provided feeds and the AWS Simple Notification Service (SNS) pilot.

Key Takeaways

• No Authentication Required: IPAWS provides publicly accessible REST feeds with no API keys,

• Feed Types: IPAWS exposes feeds for Emergency Alert System (EAS), Non-Weather Emergency

• Polling Best Practices: FEMA recommends polling **no more frequently than every 2 minutes

• CAP XML Support: Feeds return CAP 1.2 XML payloads. The poller automatically parses these

• Source Tracking: Alerts stored in PostGIS are stamped with their originating feed

• Caching Implemented: EAS Station uses PostgreSQL + PostGIS for persistent storage and Redis

• SNS Push Option: IPAWS is piloting AWS SNS topics for push-style integrations (email,

REST Feed Consumption Strategy

1. Start in Staging (Testing Environment)

Use the STAGING environment during development and QA. These feeds contain test alerts:

In .env file:
IPAWSCAPFEEDURLS=https://tdl.apps.fema.gov/IPAWSOPENEAS_SERVICE/rest/public/recent/{timestamp}
POLLINTERVALSEC=120  # 2 minutes (FEMA recommended)

2. Transition to Production (Live Alerts)

After thorough testing in staging, switch to PRODUCTION endpoints for real alerts:

In .env file:
IPAWSCAPFEEDURLS=https://apps.fema.gov/IPAWSOPENEAS_SERVICE/rest/public/recent/{timestamp}
POLLINTERVALSEC=120  # 2 minutes (FEMA recommended)

3. Polling and Caching (Already Implemented)

EAS Station implements FEMA's best practices:

• ✅ 2-Minute Polling: Default interval is 120 seconds (configurable via POLLINTERVALSEC)
• ✅ Automatic Caching: PostgreSQL + PostGIS for persistent storage, Redis for runtime cache
• ✅ Deduplication: Alerts are deduplicated by identifier + sent timestamp automatically
• ✅ Source Tracking: All alerts are stamped with source (NOAA/IPAWS/MANUAL) in database
• ✅ Exponential Backoff: On errors, polling backs off exponentially (60s → 120s → 240s → 300s)

4. Alert Distribution

Alerts are automatically distributed through:

• Web Dashboard: Real-time map display with alert details
• REST API: /api/alerts endpoint for programmatic access
• WebSockets: Real-time push to connected clients
• LED/OLED Displays: Physical alert indicators (if configured)
• EAS Broadcast: SAME/EAS encoding and audio generation (if enabled)
• GPIO Triggers: Hardware relay control for external systems

SNS Pub/Sub Integration Strategy

1. Subscription Setup

• Request addition of our preferred endpoint (e.g., HTTPS webhook or Amazon Kinesis Data

• Ensure the endpoint can receive and acknowledge SNS subscription confirmation

1. Message Handling

• SNS delivers the same payloads as the Public feed. Validate the message signature,

• Consider using SNS as a trigger to accelerate pull-based refreshes when the polling

1. Fallback and Monitoring

• Keep the REST polling flow active as a fallback until SNS topics reach parity for all

• Instrument metrics on delivery latency, failures, and retry counts.

Quick Start Guide

1. Configure IPAWS Feed

Edit your .env file (or /app-config/.env in persistent environments):

Start with STAGING for testing
IPAWSCAPFEEDURLS=https://tdl.apps.fema.gov/IPAWSOPENEAS_SERVICE/rest/public/recent/{timestamp}
POLLINTERVALSEC=120  # 2 minutes (FEMA recommended)
After testing, switch to PRODUCTION
IPAWSCAPFEEDURLS=https://apps.fema.gov/IPAWSOPENEAS_SERVICE/rest/public/recent/{timestamp}

2. Restart the IPAWS Poller

docker compose restart ipaws-poller

3. Monitor Alert Ingestion

Check the logs to verify alerts are being received:

docker compose logs -f ipaws-poller

You should see logs like:

Successfully fetched X alerts from IPAWS feed
Saved Y new alerts to database

4. View Alerts in Dashboard

Open your EAS Station web interface and navigate to the alerts dashboard to see incoming IPAWS alerts on the map.

Optional: SNS Push Integration

For push-based alert delivery instead of polling:

1. Contact IPAWS Engineering Branch (fema-ipaws-eng@fema.dhs.gov) to request SNS topic subscription
2. Implement webhook endpoint (e.g., /api/ipaws/sns) to handle SNS notifications
3. Configure your endpoint to process both subscription confirmation and alert notification messages
4. Keep REST polling as a fallback during SNS testing

Additional Resources

• IPAWS All-Hazard Info Feed overview
• AWS SNS HTTP/HTTPS endpoint setup guide