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MongoDB Atlas vs PostHog

MongoDB Atlas logo

MongoDB Atlas

Technology

The multi-cloud developer data platform

From
Free
Rated
-
Full reviewWebsite
PostHog logo

PostHog

Technology

The single platform to analyze, test, observe, and deploy new features

From
Free
Rated
-
Full reviewWebsite

The short version

  • Each has a real cost: MongoDB Atlas m0 free tier limited to learning and exploration only with no backup capability; PostHog the free tier covers 1M events, 5K web session recordings and 2.5K mobile recordings per month before usage-based billing starts
  • Prices and features above were last checked on 30 August 2026.

Where they differ

Only the attributes on which MongoDB Atlas and PostHog actually diverge.

Attributes where MongoDB Atlas and PostHog differ
AttributeMongoDB AtlasPostHog
PlatformsWebWeb, Ios, Android, Api
FoundedUnknown2020

Identical on both: starting price (Free), pricing model (usage-based), 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 PostHog does not also cover.

Only in PostHog

  • Product analytics
  • Session recording
  • Feature flags
  • A/B testing
  • Heatmaps
  • SQL access
  • Data warehouse
  • Apps platform

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 PostHog
  • Performing full-text and vector search on unstructured datanot PostHog
  • Scaling multi-cloud deployments across AWS, Azure, GCPnot PostHog
  • Streaming event data integration with Kafkanot PostHog

PostHog

  • Product analyticsnot MongoDB Atlas
  • Feature experimentationnot MongoDB Atlas
  • User behavior trackingnot MongoDB Atlas
  • A/B testingnot MongoDB Atlas
  • Debug production issuesnot 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

PostHog

  • The free tier covers 1M events, 5K web session recordings and 2.5K mobile recordings per month before usage-based billing starts
  • Accounts without a card on file are limited to 1 project; adding one raises it to 6
  • Data retention is 1 year until a card is added, which extends it to 7 years
  • Support is community-only until the account is on a paid plan
  • Error tracking is capped at 100K exceptions and surveys at 1500 responses per month on the free tier

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

PostHog

Free
  • FreeFree
    • 1M events/month
    • 5K sessions/month
    • Unlimited users
  • Paid$undefined/month
    • $0.00031/event
    • $0.005/session
    • Advanced permissions
  • Enterprise$undefined/month
    • SAML SSO
    • Advanced security
    • Dedicated support

Which should you pick?

Choose MongoDB Atlas if

  • You want to start without paying.
MongoDB Atlas review

Choose PostHog if

  • You need product analytics.
  • You want to start without paying.
  • You work on Web, Ios, Android, Api.
  • You also want session recording.
PostHog review

Questions people ask

Is MongoDB Atlas or PostHog better?
Neither clearly leads. MongoDB Atlas starts at Free and PostHog at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, MongoDB Atlas or PostHog?
MongoDB Atlas starts at Free and PostHog at Free.
Does MongoDB Atlas or PostHog run on more platforms?
MongoDB Atlas runs on Web. PostHog runs on Web, Ios, Android, Api.
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 PostHog is typically brought in for.
What can MongoDB Atlas do that PostHog cannot?
PostHog covers Product analytics, Session recording, Feature flags, A/B testing.

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.

Source
PostHog: What does PostHog's free tier include per month?

PostHog free tier includes: 1M analytics events, 5K session replays, 1M feature flag requests, 100K error tracking exceptions, 1,500 survey responses, 1M data warehouse rows, 10K data pipeline events, 100K AI observability events, 500 PostHog AI credits, 10K workflow messages, and 10GB log ingestion. Source: https://posthog.com/pricing

Source
MongoDB 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.

Source
PostHog: How much data retention does PostHog provide on paid plans?

PostHog free tier provides 1-year data retention. Pay-as-you-go plans offer 7-year data retention across all projects, enabling longer historical analysis. Source: https://posthog.com/pricing

Source
MongoDB 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.

Source
PostHog: What percentage of PostHog users stay on the free tier?

PostHog states that 97% of companies use PostHog for free, indicating extensive free tier adoption. However, specific per-unit pricing rates for overages on paid plans are not published. Source: https://posthog.com/pricing

Source
MongoDB 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.

Source
PostHog: When does PostHog provide priority support on paid plans?

PostHog provides email or Slack support for accounts exceeding $2,000/month on pay-as-you-go plans. Specific response times and support SLAs are not detailed on their pricing page. Source: https://posthog.com/pricing

Source
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