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Databases · head to head

Firestore vs MongoDB

Firestore logo

Firestore

Databases

Flexible, scalable NoSQL cloud database from Firebase

From
Free
Rated
-
Full reviewWebsite
MongoDB logo

MongoDB

Technology

The developer data platform

From
Free
Rated
-
Full reviewWebsite

The short version

  • Each has a real cost: Firestore the no-cost Spark plan caps Standard edition at 50,000 document reads, 20,000 writes and 20,000 deletes per day; MongoDB 16 MB maximum document size limits large single objects
  • They diverge on capability: Firestore covers Document Model, MongoDB covers Document model.
  • Prices and features above were last checked on 30 August 2026.

Where they differ

Only the attributes on which Firestore and MongoDB actually diverge.

Attributes where Firestore and MongoDB differ
AttributeFirestoreMongoDB
Pricing modelfreemiumUnknown
PlatformsWeb, Ios, Android, FlutterCloud (Atlas), Self-hosted, Multi-cloud (AWS, Google Cloud, Azure)
CategoryDatabasesTechnology
Founded20112007

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 Firestore

  • Document Model
  • Real-time Updates
  • Offline Support
  • ACID Transactions
  • Expressive Queries
  • Multi-region
  • Security Rules
  • Firebase Auth

Only in MongoDB

  • Document model
  • Distributed architecture
  • ACID transactions
  • Real-time analytics
  • Full-text search
  • Time series data
  • Geospatial queries
  • Aggregation framework

What people use each for

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

Firestore

  • Storing structured application data with realtime listenersnot MongoDB
  • Backing mobile and web apps with a serverless document databasenot MongoDB
  • Building offline first apps that sync when connectivity returnsnot MongoDB

MongoDB

  • Mobile applicationsnot Firestore
  • Content managementnot Firestore
  • Real-time analyticsnot Firestore
  • IoT applicationsnot Firestore
  • Gaming backendsnot Firestore

Where each one falls short

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

Firestore

  • The no-cost Spark plan caps Standard edition at 50,000 document reads, 20,000 writes and 20,000 deletes per day
  • The Spark plan caps storage at 1 GiB and network egress at 10 GiB per month
  • Charging is per document read, so a query returning many documents bills for every one of them
  • Going beyond the free thresholds requires the pay as you go Blaze plan billed at Google Cloud rates with no fixed monthly ceiling

MongoDB

  • 16 MB maximum document size limits large single objects
  • No native JOIN support for relational data operations
  • Higher memory usage due to storing field names with each document
  • Eventual consistency in distributed deployments can cause data stale reads

Pricing, plan by plan

Firestore

Free
  • SparkFree
    • 1GB storage
    • 50K reads/day
    • 20K writes/day
  • BlazeFree
    • Pay as you go
    • Unlimited operations
    • Multi-region

MongoDB

Free
  • M0Free
    • 512 MB storage
    • Learning and exploration
  • M2$9/month
    • 2 GB storage
    • Development and testing
  • M5$25/month
    • 5 GB storage
  • M10+$56.94/month
    • Dedicated clusters for production

Which should you pick?

Choose Firestore if

  • You need document model.
  • You want to start without paying.
  • You work on Web, Ios, Android, Flutter.
  • You also want real-time updates.
Firestore review

Choose MongoDB if

  • You need document model.
  • You want to start without paying.
  • You work on Cloud (Atlas), Self-hosted, Multi-cloud (AWS, Google Cloud, Azure).
  • You also want distributed architecture.
MongoDB review

Questions people ask

Is Firestore or MongoDB better?
Neither clearly leads. Firestore starts at Free and MongoDB at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, Firestore or MongoDB?
Firestore starts at Free and MongoDB at Free.
Does Firestore or MongoDB run on more platforms?
Firestore runs on Web, Ios, Android, Flutter. MongoDB runs on Cloud (Atlas), Self-hosted, Multi-cloud (AWS, Google Cloud, Azure).
Can I use Firestore for free?
Both have a free tier, so you can try either at no cost before committing.
What is Firestore best used for?
Firestore is most often used for storing structured application data with realtime listeners, backing mobile and web apps with a serverless document database, building offline first apps that sync when connectivity returns. Of those, storing structured application data with realtime listeners and backing mobile and web apps with a serverless document database are not what MongoDB is typically brought in for.
What can Firestore do that MongoDB cannot?
Firestore covers Document Model, Real-time Updates, Offline Support, ACID Transactions. MongoDB covers Document model, Distributed architecture, ACID transactions, Real-time analytics.

Answered from the vendors’ own pages

Firestore: What are the free limits on Cloud Firestore?

The Spark Plan includes 1 GiB of stored data, 50,000 reads per day, 20,000 writes per day, and 20,000 deletes per day at no cost.

Source
MongoDB: Does MongoDB offer a free tier?

Yes. MongoDB Atlas offers an M0 free tier with 512 MB storage for learning and exploration, plus paid options starting at $9/month for M2 with 2 GB storage.

Source
Firestore: What happens when I exceed the Spark Plan free tier?

Exceeding the free tier requires upgrading to the Blaze Plan, which bills based on actual usage through Google Cloud pricing. Charges apply for reads, writes, deletes, and data storage.

Source
MongoDB: Can I self-host MongoDB?

Yes. You can run MongoDB Community Edition on your own servers, or use MongoDB Enterprise Advanced for self-managed production deployments with enterprise features.

Source
Firestore: Can I use Firestore without a credit card?

Yes, you can use the Spark Plan indefinitely without a credit card. To use the Blaze Plan (pay-as-you-go), a credit card is required.

Source
MongoDB: What is the maximum document size in MongoDB?

Documents are limited to 16 MB. For documents exceeding this limit, you can use MongoDB's GridFS API to store files larger than the maximum size.

Source
Firestore: Is there a trial period for Cloud Firestore?

No trial period is specified. The Spark Plan free tier serves as the trial, with no time limit.

Source
MongoDB: Does MongoDB support ACID transactions?

Yes. MongoDB supports ACID transactions within a single document by default, and multi-document ACID transactions are available for replica sets and sharded clusters in MongoDB 4.0+.

Source
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