Firebase Cloud Messaging (FCM) Compared to OneSignal

When choosing between providers for push notifications, mobile application marketers and developers often evaluate Firebase Cloud Messaging (FCM) and OneSignal, two of the most popular push notification providers on the market.

Both Firebase and OneSignal are free to start, but they do different jobs. FCM is the delivery layer Google maintains for push on Android, iOS, and the web. OneSignal is a full customer engagement platform that sits on top of that delivery layer (and Apple's APNs), adding the dashboard, segmentation, journeys, and extra channels around it.

Our founders built OneSignal in 2015 after running into the limits of basic push delivery with their own games. The platform has grown up since then, and it's designed for marketers and developers alike, whether you're sending a first push on a free plan or running campaigns at enterprise scale.

Read on to see how the two compare today, from channels and reliability to features and price.

What is Firebase Cloud Messaging?

Firebase Cloud Messaging represents two products offered by Google as part of their Firebase suite of developer tools.

The first product is an API called “Cloud Messaging,” which apps use to send notifications to people who have downloaded their Android applications. This Android cloud API used to be called "Google Cloud Messaging" before the Firebase acquisition. For Android devices with Google Play services, FCM is the route messages travel.

This requirement exists to reduce battery consumption on Android devices. Rather than allowing all Android applications to create separate background connections for notifications, Google mandates that Android apps distributed through Google Play leverage a single, shared connection provided by FCM. Google then has an API to send messages to applications through this connection with the FCM API. Due to this requirement, OneSignal itself uses the FCM API internally to send messages to Android devices.

The FCM API can also be used to send notifications to iOS devices, where Firebase forwards messages to the Apple Push Notification Service (APNs). APNs is similar to and exists for the same reasons as the FCM API.

The second product is the Firebase Notifications composer. Developers and marketers can use it to create push notifications in an online dashboard, send them to a chosen audience (including imported segments), run A/B tests, and view delivery and engagement analytics.

Separately from Firebase Cloud Messaging, Firebase also offers In-App Messaging, a product for creating pop-up messages in the Firebase dashboard and showing them to people while they're using your app. Firebase still labels it as beta.

What is OneSignal?

OneSignal is an omnichannel customer engagement platform that enables marketers and developers to send messages to their users across multiple channels. The company was started in 2015, after our founders personally experienced the challenges of sending effective push notifications to players of their games and saw a need for a better solution.

Today, OneSignal is trusted by more than 2 million businesses and powers messaging for 1.5 billion monthly active users across 200,000 apps. It makes it easy to add mobile push, web push, email, SMS, RCS, in-app messaging, and Live Activities to your product.

Even more importantly, OneSignal helps marketers send effective messages, by providing simple and powerful tools for customer journey automation with Journeys, segmentation, personalization, and orchestration of messages across channels. OneSignal AI and the OneSignal MCP server also help you draft and analyze campaigns without leaving your workflow.

Since its founding, OneSignal has grown rapidly, thanks to the support of our loyal customers and the growing worldwide popularity of the platform. We continue to invest heavily in our best-in-class push notification product.

OneSignal and Firebase Comparison Chart

While both Firebase and OneSignal can be used to send mobile push notifications, the two platforms have many key differences. Here's an overview of some of them.

What is Firebase’s history, and where is it headed?

Firebase was a startup that was acquired by Google in 2014. In its first few years, Google significantly enhanced the Firebase platform. Other Google products, including “Google Cloud Messaging,” “Google Analytics for Mobile,” “Admob,” and others, were transferred to be a part of the growing Firebase product suite. Google Cloud Messaging became Firebase Cloud Messaging. Google Analytics for Mobile became Firebase Analytics. Even Admob, Google’s mobile advertising product, became a part of Firebase.

Firebase is now a broad suite of developer products, including Authentication, Firestore, Hosting, Crashlytics, Remote Config, and more recently Firebase AI Logic. Cloud Messaging is one product among many.

Google has kept FCM running and maintained. The legacy send APIs were retired in 2024 in favor of the HTTP v1 API, and the docs now cover iOS Live Activities and AI insights for messaging campaigns. Firebase’s own blog and documentation lead with AI, agent skills, and backend products, with messaging a smaller part of the story.

FCM also remains the delivery layer behind most Android push, including OneSignal’s own Android sends, so it isn’t going anywhere. What it offers is a dependable pipe and a lightweight composer. The campaign tooling around it is where most teams outgrow it.

The blog tells the same story. Firebase’s Cloud Messaging category has only a handful of posts since 2023.

Reliability & Platform Support

Nothing is more important than ensuring your notifications are always working smoothly. OneSignal publishes uptime for push, email, SMS, in-app messages, Journeys, and the API on its public status page, so you can check reliability yourself instead of taking our word for it.

Firebase also publishes Cloud Messaging incident history on its own status dashboard. No provider is perfect, so it's worth looking at both before you commit.

Since OneSignal must leverage FCM to deliver push notifications to Android devices, OneSignal works diligently to avoid any impacts from bugs within Google’s systems. In the vast majority of cases, OneSignal can avoid or quickly workaround issues that occur with the FCM API.

To further reduce the chance of OneSignal being impacted by Google outages, OneSignal avoids using features within FCM which are known to have more frequent issues. For example, for iOS notifications, OneSignal connects to Apple’s Notification servers directly, and we do not use FCM. For Android notifications, OneSignal avoids Firebase features like Topic Messaging which can have unpredictable performance characteristics, and OneSignal has advanced mechanisms to retry messages in case of failures.

OneSignal also has a 24/7 worldwide Site Reliability team. With 1.5 billion monthly active users and 200,000 apps depending on the platform, reliable and consistent performance is a must.

Features

The Firebase Notifications composer covers the essentials: title, text, an image, scheduling, audience targeting, and A/B tests. It works well for test sends and straightforward campaigns.

More advanced options, such as action buttons and iOS notification subtitles, are generally set through custom payloads in your own code instead of fields in the composer.

In comparison, OneSignal’s notification composer previews each device type, and supports action buttons, rich media, and subtitles as native fields.

In addition, OneSignal natively supports localization of the message and substitution of user attributes into a message (such as “first_name”) with full Liquid Templating support. OneSignal also supports testing multiple variations of a message, to determine which one is most effective.

OneSignal also makes it easy to orchestrate messages across multiple channels with Journeys. FCM sends push only. It has no email or SMS, and no cross-channel orchestration.

Creating a multi-step journey in OneSignal.

OneSignal has user profiles, which show a user’s attributes along with the messages they’ve been sent, which ones were received, and when they clicked. Firebase’s messaging reports are campaign-level, so a per-user view takes extra work with Analytics and BigQuery.

Firebase In-App Messaging is still in beta and offers a limited set of layouts. Here’s a screenshot of the in-app message creation experience in Firebase:

In comparison, OneSignal makes it easy to create beautiful in-app messages using a simple drag-and-drop UI, or with custom HTML, CSS, and Javascript.

OneSignal’s In-App Message Drag-and-Drop UI.

Overall, OneSignal’s interface gives marketers more depth than the Firebase notifications composer.

On the API side, OneSignal is built for multichannel sending, while FCM’s APIs are built for push delivery.

OneSignal has detailed API documentation with request examples for each endpoint, plus server-side SDKs.

Ultimately OneSignal provides many essential features that Firebase lacks and arms marketers and developers with the tools and documentation they need to be successful.

Price

Both OneSignal and Firebase offer free plans that provide a great way to get started. FCM itself is free. Costs tend to show up in the Firebase products around it, such as the Cloud Storage or Hosting you might use to serve notification images, which are billed by usage.

Usage-based billing is flexible, but it’s harder to forecast, and a small coding error can show up as a surprise on the invoice.

OneSignal’s Free plan includes all channels, with unlimited mobile push and in-app messaging for up to 1,000 monthly active users, 10,000 emails a month, and web push to up to 10,000 subscribers per send. Paid Growth plans start at $19 a month, with mobile push priced per monthly active user.

OneSignal also hosts notification and in-app images for you, so there’s no separate storage bill.

For more advanced functionality and personalization, OneSignal’s paid plans are simple to understand, with no extra charge for API calls.

Conclusion

FCM is a dependable way to deliver push, and plenty of teams start there. If you need more than delivery, meaning segmentation, journeys, multiple channels, and reporting in one place, OneSignal is built for that.

Our customers agree. Joan Martin from Mobile Jazz says:

"[Why not] use Firebase as a hub for everything, including push notifications? Well, OneSignal does it better."

G2 also rates OneSignal as a Leader. As one example, real OneSignal user, Ahmed S, wrote a review on G2 that describes some of the problems OneSignal helped solve in comparison to Firebase:

Learn More with OneSignal

If you don't yet have a OneSignal account, you can create one for free and start sending push notifications, emails, SMS and RCS messages, and in-app messages to your users today. Whether you’re looking for a world-class solution for your marketing needs or a robust API to send your transactional notifications, OneSignal has you covered. You can sign up and see for yourself.