Apache CouchDB

What is Apache CouchDB?

CouchDB stores JSON documents and speaks both HTTP and the replication protocol, which means clients can hold their own copy and sync changes bidirectionally. It is the database choice when offline-first matters.

Best for

Apps that need offline-capable two-way sync

Why choose Apache CouchDB

CouchDB's distinguishing feature is replication, and it is a design commitment rather than a feature. Every CouchDB instance can sync bidirectionally with any other, resolving conflicts deterministically, which means an application can keep working while offline and reconcile when connectivity returns. That makes it unusually well suited to field devices, mobile clients and multi-site deployments where the network is the least reliable component. Documents are plain JSON served over HTTP, so you can inspect and manipulate data with curl, and its append-only storage engine means a crash mid-write does not corrupt existing records. For sync-first applications it fits the problem in a way relational databases simply do not.

Replaces

• Firebase Firestore
• MongoDB
• PouchDB Cloud

Key features

• HTTP and JSON native API
• Built-in multi-master replication
• MapReduce views and Mango queries
• Fault-tolerant append-only storage

What to watch out for

Conflict resolution is the price of replication, and it is not automatic at the semantic level. CouchDB picks a winner deterministically and keeps the losing revisions, but deciding what the merged document should actually mean is your application's job — and skipping that produces data that looks fine until someone notices a field reverted. View indexes are built on demand and can be slow to warm after a restart or on first query. The database is document-oriented with no joins, so relational questions become map/reduce work you maintain yourself. Its community and ecosystem are smaller than MongoDB's, meaning fewer guides and less third-party tooling when something goes wrong.

How to deploy

• Docker or package install
• Set the admin password and bind correctly
• Replicate to a second host for resilience

Getting started

Enable the admin account and bind it to an internal interface, because an open CouchDB with replication enabled is an open door. Design your document IDs and replication filters before writing data, since changing the replication topology after the fact means reconciling everything again. Build your views early and understand that they are pre-computed indexes requiring rebuild after code changes. Decide explicitly how conflicts will be resolved in the application and implement that logic, rather than discovering the problem in production. Back up by replicating to a second instance or by using the replication API, and test that a restore actually produces a working database.

Typical setup

One or more instances with an admin account configured and bound to an internal interface, and replication relationships defined deliberately rather than discovered. Document IDs and replication filters are designed before data is written, because changing the topology later means reconciling everything again. Views are built ahead of the queries that need them and rebuilt as part of deployment. Conflict resolution logic lives in the application and is tested, and backups are made by replicating to a separate instance, with a restore proven rather than assumed.

Who should look elsewhere

Do not choose CouchDB for data with strong relational structure or a need for multi-document transactions — the document model and eventual consistency will fight you. Avoid it if you cannot commit to writing conflict resolution logic, because replication without it will silently lose edits. And if your application only ever talks to one server with a reliable network, the feature you are paying for in complexity is one you will never use.

Project health

• GitHub stars: 6,967
• Last code push: 2026-10-01
• Open issues: 379
• Status: actively developed

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