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Databases · head to head

Firebase Realtime Database vs Zilliz

Firebase Realtime Database logo

Firebase Realtime Database

Databases

Store and sync data in real-time across all clients

From
Free
Rated
-
Full reviewWebsite
Zilliz logo

Zilliz

Databases

Managed vector database and vector lakebase for AI applications

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; Zilliz pricing structure not publicly disclosed, requires sales contact
  • They diverge on capability: Firebase Realtime Database covers Real-time Sync, Zilliz covers Vector indexing.
  • Prices and features above were last checked on 30 August 2026.

Where they differ

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

Attributes where Firebase Realtime Database and Zilliz differ
AttributeFirebase Realtime DatabaseZilliz
Pricing modelfreemiumcontact-sales
PlatformsWeb, Ios, AndroidCloud, Self-hosted
Founded20112017

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 Zilliz

  • Vector indexing
  • Distributed architecture
  • SQL interface
  • Tensor support
  • Real-time search
  • Cloud-native
  • Open-source compatible

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 Zilliz
  • Backing mobile and web apps with offline capable data storagenot Zilliz
  • Prototyping realtime features such as presence and chatnot Zilliz

Zilliz

  • Build retrieval-augmented generation (RAG) systemsnot Firebase Realtime Database
  • Implement semantic search over documentsnot Firebase Realtime Database
  • Create multimodal search with text and imagesnot Firebase Realtime Database
  • Power recommendation engines with vector similaritynot Firebase Realtime Database
  • Enable similarity search on user embeddingsnot 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

Zilliz

  • Pricing structure not publicly disclosed, requires sales contact
  • Operational complexity for self-hosted Milvus deployments
  • Learning curve for those unfamiliar with vector databases
  • Limited built-in analytics compared to some alternatives

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

Zilliz

Free

No published plan breakdown. See the Zilliz review.

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 Zilliz if

  • You need vector indexing.
  • You want to start without paying.
  • You work on Cloud, Self-hosted.
  • You also want distributed architecture.
Zilliz review

Questions people ask

Is Firebase Realtime Database or Zilliz better?
Neither clearly leads. Firebase Realtime Database starts at Free and Zilliz at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, Firebase Realtime Database or Zilliz?
Firebase Realtime Database starts at Free and Zilliz at Free.
Does Firebase Realtime Database or Zilliz run on more platforms?
Firebase Realtime Database runs on Web, Ios, Android. Zilliz runs on Cloud, 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 Zilliz is typically brought in for.
What can Firebase Realtime Database do that Zilliz cannot?
Firebase Realtime Database covers Real-time Sync, Offline Support, JSON Storage, Security Rules. Zilliz covers Vector indexing, Distributed architecture, SQL interface, Tensor support.

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
Zilliz: What is the difference between Milvus and Zilliz Cloud?

Milvus is the open-source vector database that you can self-host. Zilliz Cloud is the fully managed service built on Milvus that removes operational overhead and handles scaling automatically.

Source
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
Zilliz: How many vectors can Zilliz handle?

Milvus and Zilliz Cloud can store and search billions of vectors through their distributed architecture that separates storage and compute layers.

Source
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
Zilliz: Is Milvus open-source?

Yes, Milvus is open-source under the Apache License 2.0 and is part of the LF AI & Data Foundation.

Source
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
Zilliz: What pricing does Zilliz Cloud offer?

Zilliz Cloud pricing is not publicly listed and requires contacting their team to discuss your specific scale and use case requirements.

Source
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