Technology · head to head
MongoDB Atlas vs Postgres
The short version
- Each has a real cost: MongoDB Atlas m0 free tier limited to learning and exploration only with no backup capability; Postgres each major version is supported for only 5 years after its initial release, after which it is end-of-life
- Prices and features above were last checked on 30 August 2026.
Where they differ
Only the attributes on which MongoDB Atlas and Postgres actually diverge.
| Attribute | MongoDB Atlas | Postgres |
|---|---|---|
| Pricing model | usage-based | open-source |
| Platforms | Web | Linux, Windows, Macos, Docker |
| Founded | Unknown | 1996 |
Identical on both: starting price (Free), free tier (Yes), user rating (Not yet rated), category (Technology).
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 MongoDB Atlas
Nothing recorded that Postgres does not also cover.
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.
MongoDB Atlas
- Building applications with flexible JSON document storagenot Postgres
- Performing full-text and vector search on unstructured datanot Postgres
- Scaling multi-cloud deployments across AWS, Azure, GCPnot Postgres
- Streaming event data integration with Kafkanot Postgres
Postgres
- Running a general purpose relational database for applicationsnot MongoDB Atlas
- Self-hosting an open source SQL database with no licence feenot MongoDB Atlas
- Workloads needing extensions, JSON and full text search in one enginenot MongoDB Atlas
Where each one falls short
Documented limitations, not opinions. Every one is a constraint you would hit in normal use.
MongoDB Atlas
- M0 free tier limited to learning and exploration only with no backup capability
- Data transfer egress charges apply at 0.12 USD/GB for dedicated clusters; inbound free
- MongoDB Search and Vector Search add significant per-hour costs starting at 0.12 USD/hour
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
MongoDB Atlas
Free- M0 (Free Tier)Free
- 512 MB storage
- Shared RAM and vCPU
- No backups
- Flex Tier$0.011/hour
- 5 GB storage
- Shared RAM and vCPU
- Pay-as-you-go hourly billing
- M2 Shared$9/month
- 2 GB storage
- Shared RAM and vCPU
- M5 Shared$25/month
- 5 GB storage
- Shared RAM and vCPU
Postgres
Free- Community EditionFree
- Full database features
- No limitations
- Community support
Which should you pick?
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.
Questions people ask
- Is MongoDB Atlas or Postgres better?
- Neither clearly leads. MongoDB Atlas 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, MongoDB Atlas or Postgres?
- MongoDB Atlas starts at Free and Postgres at Free.
- Does MongoDB Atlas or Postgres run on more platforms?
- MongoDB Atlas runs on Web. Postgres runs on Linux, Windows, Macos, Docker.
- Can I use MongoDB Atlas for free?
- Both have a free tier, so you can try either at no cost before committing.
- What is MongoDB Atlas best used for?
- MongoDB Atlas is most often used for building applications with flexible json document storage, performing full-text and vector search on unstructured data, scaling multi-cloud deployments across aws, azure, gcp, streaming event data integration with kafka. Of those, building applications with flexible json document storage and performing full-text and vector search on unstructured data are not what Postgres is typically brought in for.
- What can MongoDB Atlas do that Postgres cannot?
- Postgres covers ACID compliance, Complex queries, Foreign keys, Triggers.
Answered from the vendors’ own pages
MongoDB Atlas: How much does MongoDB Atlas cost?
MongoDB Atlas offers a free M0 tier with 512 MB storage, Flex tier at approximately 8-30 USD/month with pay-per-hour billing, shared clusters at 9-25 USD/month, and dedicated clusters from 56.94 USD/month. Add-on services like MongoDB Search cost 0.12-3.27 USD/hour.
SourcePostgres: 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
SourceMongoDB Atlas: Is there a free tier?
Yes, MongoDB Atlas M0 free tier offers 512 MB storage with shared resources, suitable for learning and exploration. Flex tier allows pay-as-you-go usage starting at 0.011 USD/hour.
SourcePostgres: 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
SourceMongoDB Atlas: What are the data transfer limits?
Inbound data transfer is typically free; egress from dedicated clusters costs 0.12 USD/GB. Free and Flex tiers do not incur data transfer charges.
SourcePostgres: 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
SourceMongoDB Atlas: What backup options are available?
M0 free tier and Flex tier do not include backups. Dedicated clusters M10 and above include backup services with region and snapshot storage-based pricing.
SourceRelated pages
More on MongoDB Atlas
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