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Firebase Realtime Database vs Postgres

Firebase Realtime Database logo

Firebase Realtime Database

Databases

Store and sync data in real-time across all clients

From
Free
Rated
-
Full reviewWebsite
Postgres logo

Postgres

Technology

The world's most advanced open source database

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; Postgres each major version is supported for only 5 years after its initial release, after which it is end-of-life
  • They diverge on capability: Firebase Realtime Database covers Real-time Sync, Postgres covers ACID compliance.
  • Prices and features above were last checked on 30 August 2026.

Where they differ

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

Attributes where Firebase Realtime Database and Postgres differ
AttributeFirebase Realtime DatabasePostgres
Pricing modelfreemiumopen-source
PlatformsWeb, Ios, AndroidLinux, Windows, Macos, Docker
CategoryDatabasesTechnology
Founded20111996

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

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 Postgres

  • ACID compliance
  • Complex queries
  • Foreign keys
  • Triggers
  • Views
  • Stored procedures
  • JSON/JSONB support
  • Full-text 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 Postgres
  • Backing mobile and web apps with offline capable data storagenot Postgres
  • Prototyping realtime features such as presence and chatnot Postgres

Postgres

  • Running a general purpose relational database for applicationsnot Firebase Realtime Database
  • Self-hosting an open source SQL database with no licence feenot Firebase Realtime Database
  • Workloads needing extensions, JSON and full text search in one enginenot 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

Postgres

  • Each major version is supported for only 5 years after its initial release, after which it is end-of-life
  • Major version upgrades break on-disk compatibility and require a full dump and reload or the pg_upgrade tool
  • New major versions ship about once a year, so staying supported means a disruptive upgrade cycle
  • Minor releases contain only frequently-encountered bug fixes, low-risk fixes, security issues and data corruption fixes, so feature gaps are not addressed within a major version
  • There is no vendor SLA; commercial support must be bought separately from third party professional services listed by the project

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

Postgres

Free
  • Community EditionFree
    • Full database features
    • No limitations
    • Community support

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 Postgres if

  • You need acid compliance.
  • You want to start without paying.
  • You work on Linux, Windows, Macos, Docker.
  • You also want complex queries.
Postgres review

Questions people ask

Is Firebase Realtime Database or Postgres better?
Neither clearly leads. Firebase Realtime Database starts at Free and Postgres at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, Firebase Realtime Database or Postgres?
Firebase Realtime Database starts at Free and Postgres at Free.
Does Firebase Realtime Database or Postgres run on more platforms?
Firebase Realtime Database runs on Web, Ios, Android. Postgres runs on Linux, Windows, Macos, Docker.
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 Postgres is typically brought in for.
What can Firebase Realtime Database do that Postgres cannot?
Firebase Realtime Database covers Real-time Sync, Offline Support, JSON Storage, Security Rules. Postgres covers ACID compliance, Complex queries, Foreign keys, Triggers.

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
Postgres: How much does PostgreSQL cost to use?

PostgreSQL is completely free to download, install, and use. No licensing fees, subscription costs, or per-seat charges apply. The database is open source under the PostgreSQL License. Source: https://www.postgresql.org

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
Postgres: Are there commercial PostgreSQL support options available?

Official PostgreSQL (the project) is free. Commercial PostgreSQL services such as hosting, professional support, training, and managed database services are offered by third-party vendors, not the PostgreSQL project itself. Source: https://www.postgresql.org

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
Postgres: Do I need a license to use PostgreSQL commercially?

No. PostgreSQL is open source under the PostgreSQL License, which permits free commercial use without royalties, licensing fees, or support obligations. Source: https://www.postgresql.org

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
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