Ably vs Firebase(2026)
Ably is better for teams that need message ordering guaranteed. Firebase is the stronger choice if real-time sync out of the box. Ably is freemium (from $0 (free 6M messages/month)) and Firebase is freemium (from $25/month).
Full feature breakdown, pricing details, and pros & cons below.
By Bikram NathLast updated
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Ably
Ably is a realtime messaging platform with guaranteed delivery, ordering, and a global edge network.
Starting at $0 (free 6M messages/month)
Visit AblyFirebase
Firebase is Google's app development platform with realtime database, Firestore, auth, hosting, and cloud functions.
Starting at $25/month
Visit FirebaseHow Do Ably and Firebase Compare on Features?
| Feature | Ably | Firebase |
|---|---|---|
| Pricing model | freemium | freemium |
| Starting price | $0 (free 6M messages/month) | $25/month |
| Pub/Sub | ✓ | — |
| Presence | ✓ | — |
| Message history | ✓ | — |
| Push notifications | ✓ | — |
| Server-sent events | ✓ | — |
| MQTT support | ✓ | — |
| Firestore (NoSQL) | — | ✓ |
| Realtime Database | — | ✓ |
| Authentication | — | ✓ |
| Cloud Functions | — | ✓ |
| Hosting | — | ✓ |
| Storage | — | ✓ |
| App Check | — | ✓ |
Ably Pros and Cons vs Firebase
Ably
Firebase
Deep dive: Firebase
When to choose Firebase
Choose Firebase if you're building a real-time collaborative app (Figma-like, live polling, chat) and want backend complexity handled by Google. Also ideal if you're starting a mobile app and need SDK convenience (auth, push notifications, analytics). Real-time Firestore sync is genuinely hard to replicate manually—handling subscriptions, conflict resolution, and multi-client consistency requires weeks of engineering. Great for small teams without backend expertise who just want to ship fast. Firebase is wrong if you need complex transactions, want control over data location/compliance, need to optimize costs (Firebase becomes expensive at moderate scale—$1k+/month quickly), or plan to outgrow it. Vendor lock-in is real; exporting Firestore data to Postgres is manual and lossy. Also wrong if you need SQL-like joins or plan to run complex analytics queries. Firestore forces denormalization, and backfilling denormalized copies when source data changes is tedious. Teams with strict GDPR requirements or data residency needs should avoid Firebase.
Real-world use case
A team of 2 built a collaborative whiteboard app using Firebase, needing real-time sync of canvas changes across 5+ concurrent users. On traditional Postgres + WebSockets, this would've been 2-3 weeks of engineering (managing subscriptions, conflict resolution). With Firebase Firestore's real-time listeners, every pen stroke synced to all users within 200ms; conflicts resolved automatically. Cost: $0 first month (free tier), then $150/month at peak (3k concurrent draws/day). Real numbers: they hit Firebase's default concurrent connection limit (100) at only 45 simultaneous users, forcing an upgrade. Real tradeoff: when adding a 'comments' feature, Firestore's lack of joins forced them to duplicate user names in every comment doc. Later, redesigning the user profile meant manually updating 10k comments—something a single SQL UPDATE would've solved in 50ms. They chose Firebase over building WebSocket infrastructure because the time savings were critical; reaching production in 5 days vs. 4 weeks justified the eventual cost.
Hidden gotchas
Billing is per read, write, and delete operation. A single document change counts as 1 write. If 100 users listen to the same document via real-time listeners and it changes once, that's 100 reads billed instantly. At scale, this becomes insanely expensive—a busy chatroom can rack up $500+ in daily read costs from a single change. Firestore's 'eventually consistent' reads return stale data. Google downplays this in docs, but writes to one region aren't instantly visible in another, leading to subtle race conditions in production that are nearly impossible to debug. Exporting data from Firebase is manual and incomplete. There's no built-in export-to-CSV for large datasets. Nested documents (e.g., user { profile { address } }) flatten awkwardly when exported. Authentication ties you to Google's OAuth/email systems; migrating to a different provider later is a months-long project because auth is baked into client SDKs. The free tier has a 1GB storage limit enforced harshly—one day you're building freely, the next day you get a quota-exceeded error. Google doesn't warn when approaching limits. Subcollections are stored differently than top-level collections, causing unexpected billing surprises. Array operations (adding one element to a 1k-element array) require reading and writing the entire array—performance scaling is nonlinear.
Pricing breakdown
Firebase's free Spark plan includes 1 GB Firestore storage, 50K reads/day, 20K writes/day, and 10 GB hosting bandwidth. The Blaze (pay-as-you-go) plan charges $0.06 per 100K reads, $0.18 per 100K writes, and $0.18/GB storage. Realtime Database is $5/GB stored and $1/GB downloaded. The real cost shock comes from Firestore reads — a poorly optimized query that reads 100 documents per page view can cost $150+/mo at 50K daily users. Cloud Functions are billed at $0.40 per million invocations plus compute time. A typical mobile app backend costs $20-100/mo on Blaze.
Should You Use Ably or Firebase?
For most teams, Ably is the better default: it offers message ordering guaranteed and is freemium (from $0 (free 6M messages/month)). Choose Firebase instead if real-time sync out of the box matters more than more complex than pusher. There is no universal winner — the right pick depends on your budget, team size, and whether you value message ordering guaranteed or real-time sync out of the box more.
Choose Ably if…
- •Message ordering guaranteed
- •Generous free tier
- •Global edge network
Choose Firebase if…
- •Real-time sync out of the box
- •Complete backend platform
- •Excellent mobile SDKs