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Databases · head to head

Firebase Realtime Database vs OpenSearch

Firebase Realtime Database logo

Firebase Realtime Database

Databases

Store and sync data in real-time across all clients

From
Free
Rated
-
Full reviewWebsite
OpenSearch logo

OpenSearch

Databases

Open-source search and analytics suite forked from Elasticsearch

From
Free
Rated
-
Full reviewWebsite

The short version

  • Each has a real cost: Firebase Realtime Database the no-cost Spark plan caps storage at 1 GB, downloads at 10 GB per month and simultaneous connections at 100; OpenSearch diverged from Elasticsearch since 7.10, so clients, plugins and features no longer map one to one
  • They diverge on capability: Firebase Realtime Database covers Real-time Sync, OpenSearch covers Full-text search.
  • Prices and features above were last checked on 30 August 2026.

Where they differ

Only the attributes on which Firebase Realtime Database and OpenSearch actually diverge.

Attributes where Firebase Realtime Database and OpenSearch differ
AttributeFirebase Realtime DatabaseOpenSearch
Pricing modelfreemiumOpen source, no licence fee; managed services billed separately
PlatformsWeb, Ios, AndroidLinux, Docker, Kubernetes, Self-hosted
Founded2011Unknown

Identical on both: starting price (Free), free tier (Yes), user rating (Not yet rated), category (Databases).

What each one covers

Drawn from each product's published feature list. An absence here means we hold no record of it - not that the product lacks it.

Only in Firebase Realtime Database

  • Real-time Sync
  • Offline Support
  • JSON Storage
  • Security Rules
  • Data Validation
  • Multi-platform SDKs
  • Scalable
  • Firebase Auth

Only in OpenSearch

  • Full-text search
  • OpenSearch Dashboards
  • Log analytics
  • Vector search

What people use each for

The jobs each tool is most often brought in to do.

Firebase Realtime Database

  • Syncing JSON application state between clients in real timenot OpenSearch
  • Backing mobile and web apps with offline capable data storagenot OpenSearch
  • Prototyping realtime features such as presence and chatnot OpenSearch

OpenSearch

  • Log and observability storage where an Apache-2.0 licence is a requirementnot Firebase Realtime Database
  • Replacing Elasticsearch after the licence change without changing architecturenot Firebase Realtime Database
  • Search plus analytics on one cluster rather than two systemsnot Firebase Realtime Database

Where each one falls short

Documented limitations, not opinions. Every one is a constraint you would hit in normal use.

Firebase Realtime Database

  • The no-cost Spark plan caps storage at 1 GB, downloads at 10 GB per month and simultaneous connections at 100
  • The Spark plan does not support multiple databases in a project
  • Even on the paid Blaze plan simultaneous connections are capped at 200,000 per database
  • Billing is by data transferred out at $1 per GB plus $5 per GB stored, so chatty clients cost more than the data volume suggests

OpenSearch

  • Diverged from Elasticsearch since 7.10, so clients, plugins and features no longer map one to one
  • Operationally heavy in the way Elasticsearch is: cluster sizing, shard strategy and JVM tuning are ongoing work
  • Smaller ecosystem of third-party tooling than Elasticsearch, which most integrations still target first
  • Overkill for plain application search, where a dedicated search engine is far simpler

Pricing, plan by plan

Firebase Realtime Database

Free
  • SparkFree
    • 1 GB data storage included
    • 10 GB per month data downloads included
    • No charges for usage within limits
  • Blaze$5/per_GB_per_month
    • Maintains Spark free allowances
    • Pay-as-you-go for usage exceeding limits
    • Billing applies to data stored and outbound network traffic

OpenSearch

Free
  • OpenSearchFree
    • Full functionality
    • Self-hosted
    • No usage limits

Which should you pick?

Choose Firebase Realtime Database if

  • You need real-time sync.
  • You want to start without paying.
  • You work on Web, Ios, Android.
  • You also want offline support.
Firebase Realtime Database review

Choose OpenSearch if

  • You need full-text search.
  • You want to start without paying.
  • You work on Linux, Docker, Kubernetes, Self-hosted.
  • You also want opensearch dashboards.
OpenSearch review

Questions people ask

Is Firebase Realtime Database or OpenSearch better?
Neither clearly leads. Firebase Realtime Database starts at Free and OpenSearch at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, Firebase Realtime Database or OpenSearch?
Firebase Realtime Database starts at Free and OpenSearch at Free.
Does Firebase Realtime Database or OpenSearch run on more platforms?
Firebase Realtime Database runs on Web, Ios, Android. OpenSearch runs on Linux, Docker, Kubernetes, Self-hosted.
Can I use Firebase Realtime Database for free?
Both have a free tier, so you can try either at no cost before committing.
What is Firebase Realtime Database best used for?
Firebase Realtime Database is most often used for syncing json application state between clients in real time, backing mobile and web apps with offline capable data storage, prototyping realtime features such as presence and chat. Of those, syncing json application state between clients in real time and backing mobile and web apps with offline capable data storage are not what OpenSearch is typically brought in for.
What can Firebase Realtime Database do that OpenSearch cannot?
Firebase Realtime Database covers Real-time Sync, Offline Support, JSON Storage, Security Rules. OpenSearch covers Full-text search, OpenSearch Dashboards, Log analytics, Vector search.

Answered from the vendors’ own pages

Firebase Realtime Database: How much does Firebase Realtime Database cost?

Firebase Realtime Database offers a free Spark plan (1 GB storage, 10 GB/month downloads) and a pay-as-you-go Blaze plan. On Blaze, storage costs $5 per GB per month, evaluated daily, with no monthly minimum charges.

Source
OpenSearch: Is OpenSearch free?

Yes, Apache 2.0 licensed under the Linux Foundation. Amazon OpenSearch Service is a paid managed option.

Firebase Realtime Database: What is included in Firebase Realtime Database free tier?

The Spark plan includes 1 GB of data storage and 10 GB per month of data downloads at no cost. Usage within these limits incurs no charges, making it suitable for small projects and testing.

Source
OpenSearch: Why does OpenSearch exist?

Elastic moved Elasticsearch off the Apache 2.0 licence in 2021. AWS forked the last Apache-licensed version, and the project now sits under the Linux Foundation.

Firebase Realtime Database: Does Firebase Realtime Database charge for denied or rejected operations?

Yes. Firebase charges for all traffic to and from the database on the Blaze plan, including operations denied by security rules, outbound network traffic at the session layer, and connection and encryption overhead from all operations.

Source
OpenSearch: Is OpenSearch compatible with Elasticsearch?

It was at the 7.10 fork point. Both have developed independently since, so compatibility weakens with every release and should be verified for the features you use.

Firebase Realtime Database: Can I set a spending limit on Firebase Realtime Database?

Firebase offers budget alerts but does not cap spending automatically. Users must monitor their usage dashboard in the Firebase console to track connections, storage, downloads, and load metrics; a calculator is available for cost estimation.

Source
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