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It's a split decision.
Choose Apache CouchDB when your application needs an HTTP/JSON interface and replication that can sync data across servers, phones and browsers, including offline-first use. Choose MongoDB when you want Atlas’s managed tiers, or need its listed search, vector search, stream processing and analytics services. Both support self-hosting and document data, but their deployment and pricing models differ: CouchDB is free to download, while Atlas charges by tier and usage.
01Side by side
| Apache CouchDB | MongoDB | |
|---|---|---|
| Pricing model | Free to download and self-host; no published billing options | Atlas bills hourly, with monthly invoices |
| Free tier | Free software for self-hosting | M0: 512 MB; up to 100 operations per second |
| Open source and licence | Open source; verify licence terms | Community Edition; Enterprise Advanced has a commercial licence |
| Self-hosting | Run a single node or cluster on your infrastructure | Self-managed deployments run on your infrastructure |
| API and SDKs | HTTP/JSON API; compatible with HTTP-supporting software | Document model with a single query API |
| Docs and learning | Documentation, introduction and technical overview | Documentation, community forums, University and certifications |
| Integrations | Works with HTTP proxies, load balancers and PouchDB | Integrates with 100+ technologies |
| Deployment model | Single-node database or multi-server cluster | Atlas across clouds or self-managed software |
Apache CouchDB Choose Apache CouchDB if
- Choose Apache CouchDB if you need HTTP/JSON access.
- Choose Apache CouchDB if offline-first replication is central to your app.
- Choose Apache CouchDB if you want a free, self-hosted database.
MongoDB Choose MongoDB if
- Choose MongoDB if you want managed Atlas deployment options.
- Choose MongoDB if you need its listed search or vector search services.
- Choose MongoDB if you want Atlas tiers with defined storage and usage limits.
02Pricing at real usage
Apache CouchDB is free to download and self-host. The vendor does not publish monthly or annual billing options, so infrastructure and operations costs depend on your deployment. MongoDB Atlas has a free M0 tier with 512 MB of storage, 32 MB of sort memory and up to 100 operations per second. Atlas Flex has a $0.011/hour base rate, 5 GB of storage and listed usage costs of $8–$30/month. Dedicated clusters start at $56.94/month; the listed hourly rates range from $0.08 for M10 to $33.26 for M700. Atlas bills clusters hourly and invoices monthly. Atlas Infinite is listed at $0.09/hour and is in public preview. Compare expected compute and usage against the relevant Atlas tier; for CouchDB, account for your own hosting and operations.
03API, SDKs and integration
CouchDB exposes an HTTP/JSON API, so software that supports those protocols can access it. Its Couch Replication Protocol syncs data across server clusters, mobile phones and browsers; the homepage also lists replication with PouchDB. CouchDB has a developer-friendly query language and optional MapReduce. The vendor does not name specific language SDKs. Its site provides documentation, an introduction and a technical overview.
MongoDB uses a document model with a single query API. Its platform includes database, search, vector search, stream processing, analytics and graph capabilities, with Atlas and self-managed deployment options. The homepage lists integrations with 100+ technologies, documentation, community forums and MongoDB University. It also lists Compass, a GUI for working with MongoDB data, and Relational Migrator. Neither product’s listed materials name specific SDK languages or a CLI, so check the docs for the client and tooling support your stack requires.
04Open source, self-hosting and lock-in
CouchDB is open source and can run on your own servers, as a single node or a cluster. Check its licence terms before incorporating or distributing it. Its replication protocol syncs data between supported environments, which can help applications keep copies in sync; replication is not the same as a general-purpose export format.
MongoDB supports self-managed deployments, and its homepage offers Community Edition for local development at no cost. Enterprise Advanced is listed with a commercial licence. Atlas is the managed option, available across clouds. MongoDB also lists Relational Migrator for moving applications to MongoDB, but that does not establish a general-purpose export path. Before choosing either database, verify the export formats and migration procedures you need, and test them against your schema and replication or Atlas setup.
Questions people ask
What is the difference between CouchDB and MongoDB?
Both store document data, but their integration models differ. CouchDB provides an HTTP/JSON API and a replication protocol designed to sync data across servers, phones and browsers. MongoDB offers Atlas and self-managed deployments, with listed services for search, vector search, stream processing and analytics.
Which is better for offline-first applications?
CouchDB is the clearer fit when offline-first replication is a requirement. Its Couch Replication Protocol syncs data across server clusters, mobile phones and browsers. MongoDB’s listed features cover document workloads, Atlas services and other application capabilities, but do not describe an equivalent offline-first replication feature.
Is CouchDB cheaper than MongoDB?
CouchDB is free to download and self-host, but you pay for your own infrastructure and operations. MongoDB Atlas has a free M0 tier, then paid Flex and Dedicated tiers with hourly billing. Compare your hosting costs with Atlas usage; the answer depends on workload and deployment.
Can I self-host both CouchDB and MongoDB?
Yes. CouchDB runs as a single node or cluster on your infrastructure. MongoDB offers self-managed software, including Community Edition for local development and Enterprise Advanced for enterprise deployments. MongoDB Atlas is the managed alternative, available across clouds.