OneSignal API
Multi-channel customer engagement platform enabling push notifications, email, SMS, and in-app messages via a unified API with advanced segmentation and A/B testing.
Score Breakdown
⚙ Agent Friendliness
🔒 Security
REST API key + user-auth key. App-level authentication. Push notifications reach end users — sensitive message content. No SOC2 documented. GDPR compliance for EU user notifications.
⚡ Reliability
Best When
You need a scalable, multi-channel notification system for consumer apps with segmentation and analytics built in.
Avoid When
You need only transactional email or have a very small notification audience.
Use Cases
- • Sending targeted push notifications to segmented user groups
- • Building onboarding and re-engagement notification workflows
- • Coordinating cross-channel messaging (push + email + SMS)
- • Automating notification delivery based on user behavior from agents
- • A/B testing notification content and delivery timing
Not For
- • Simple one-person alerting (use Pushover)
- • Transactional email at high volume (use SendGrid or Mailgun)
- • Real-time bidirectional messaging
Interface
Authentication
App Auth Key for sending notifications. User Auth Key (account-level) for management operations. REST API key per app.
Pricing
Generous free tier for push. Email and SMS have volume-based pricing. Free tier is genuinely usable for many apps.
Agent Metadata
Known Gotchas
- ⚠ Notification delivery is eventually consistent - status must be polled to confirm delivery
- ⚠ Segments must be pre-defined in the dashboard - agents cannot create segments on the fly via API
- ⚠ External user IDs must be set when registering devices for reliable targeting by agents
- ⚠ Free tier rate limiting (1 req/sec) is very restrictive for bulk sends
- ⚠ In-app messages require the SDK - API alone cannot trigger them for new users
Alternatives
Full Evaluation Report
Detailed scoring breakdown, competitive positioning, security analysis, and improvement recommendations for OneSignal API.
Scores are editorial opinions as of 2026-03-06.