JavaScript Database Comparison

There are several good databases for building local-first and offline-first JavaScript apps. They differ in how they store data, how query results reach your UI, how they sync with a server and what they cost. This page compares SignalDB, RxDB, Dexie.js, PouchDB, WatermelonDB, TinyBase and TanStack DB and helps you pick the right one for your project.

About this comparison

This page is written by the SignalDB maintainers. We try to be fair and point out where other projects are the better choice. Information was checked against each project's official documentation and repository. Last reviewed: October 2026. If something is outdated, please open an issue or edit this page.

At a Glance

	Short description	License
SignalDB	Reactive in-memory database with MongoDB-like queries, signal-based reactivity, persistence adapters and backend-agnostic sync	MIT
RxDB	Feature-rich NoSQL database with pluggable storages and a replication engine	Apache 2.0 core, paid Pro tiers
Dexie.js	Minimalistic wrapper for IndexedDB with live queries, optional Dexie Cloud sync service	Apache 2.0 (Dexie Cloud is a paid service with a free tier)
PouchDB	CouchDB-inspired database for the browser with built-in CouchDB sync	Apache 2.0
WatermelonDB	Lazy-loading reactive database for React and React Native, built on SQLite	MIT
TinyBase	Reactive in-memory store of tables and values with persisters and CRDT-based sync	MIT
TanStack DB	Reactive client store that extends TanStack Query with collections and live queries (beta)	MIT

Feature Comparison

	SignalDB	RxDB	Dexie.js	PouchDB	WatermelonDB	TinyBase	TanStack DB
Data model	Document collections	Document collections with JSON schema	IndexedDB tables	Documents (CouchDB model)	Tables and models	Tables and values	Typed collections
Query API	MongoDB-like selectors	Mango (MongoDB-like) queries	Index-based queries (where())	Mango queries via pouchdb-find, map/reduce	Q.where query builder	TinyQL queries	SQL-like query builder (from, where, join)
Reactivity	Uses the signals of your framework via adapters	RxJS observables, custom reactivity for signals	liveQuery() observables, useLiveQuery for React	Changes feed	Observables, React helpers	Listeners and React hooks	Live queries with framework hooks
Storage (browser)	IndexedDB, OPFS, localStorage	IndexedDB (via Dexie.js), memory and more; OPFS in paid tiers	IndexedDB	IndexedDB	LokiJS adapter	IndexedDB, localStorage and more via persisters	In memory; data is loaded through collection types
Other platforms	Node.js (file system)	Node.js, Electron, Capacitor, React Native, Tauri (SQLite in paid tiers)	Browser, Electron, Capacitor	Node.js (LevelDB)	iOS, Android (SQLite), Node.js, Windows	Node.js, React Native and more via persisters	Wherever TanStack Query runs
Sync	Built-in sync engine; you implement pull/push for any backend	Replication engine with plugins (HTTP, GraphQL, WebSocket, CouchDB, Firestore, MongoDB, WebRTC, …)	Dexie Cloud (hosted or self-hosted) or custom	Built-in two-way sync with CouchDB-compatible servers	Sync protocol you implement on your backend	CRDT-based synchronizers (WebSocket, BroadcastChannel, custom)	Through collection types (TanStack Query, ElectricSQL, PowerSync, RxDB, …)
Conflict handling	Local changes replayed on latest server data, last change wins	Conflict handler, customizable	Handled by Dexie Cloud	CouchDB revision model	Handled by your backend	CRDT merge	Depends on the sync source
Optimistic UI	Built in (all writes are local first)	Built in (local first)	Built in (local first)	Built in (local first)	Built in (local first)	Built in (local first)	Built in (optimistic mutations)
TypeScript	✅	✅	✅	Community types	✅	✅	✅

SignalDB vs. RxDB

RxDB is the most feature-complete project in this list: JSON schemas, migrations, attachments, encryption, many storages, a replication engine with ready-made plugins and support for most JavaScript runtimes. The core is open source (Apache 2.0); performance-oriented storages such as OPFS and SQLite, and some plugins, are part of paid tiers.

How SignalDB differs:

• Reactivity: RxDB is built on RxJS observables and can map them to signals with a custom reactivity factory. SignalDB is designed around signals: queries run inside your framework's effects and are tracked by its own reactivity system, with ready-made adapters for Angular, Solid, Vue, Preact, Svelte, MobX and more.
• Scope and size: SignalDB is deliberately smaller. It focuses on collections, queries, reactivity, persistence and sync, and leaves validation, schemas and storage details to adapters and your own code.
• Cost: all SignalDB packages, including the OPFS adapter, are MIT-licensed.

For a detailed one-to-one comparison with code examples, see SignalDB vs RxDB.

Choose RxDB if you need its breadth: many storages, ready-made replication plugins, encryption, React Native/Capacitor support today, or professional support. Choose SignalDB if you want a lightweight, signal-native data layer for a web app and sync with your own API.

SignalDB vs. Dexie.js

Dexie.js is a minimalistic wrapper around IndexedDB. It queries IndexedDB directly using indexes, which makes it a good fit for large datasets that should not be held in memory. liveQuery() turns queries into observables, and useLiveQuery() integrates them into React. Sync is available through Dexie Cloud, a commercial service with a free tier that can also be self-hosted.

How SignalDB differs:

• In memory vs. on disk: SignalDB keeps collections in memory and persists them, which makes queries synchronous and very fast but means all data of a collection is loaded into memory. Dexie reads from IndexedDB on demand.
• Queries: SignalDB uses MongoDB-like selectors on any field. Dexie queries work through the indexes you declare in your schema.
• Sync: SignalDB syncs with any backend through your own pull/push functions. Dexie's built-in sync is tied to Dexie Cloud.

Choose Dexie.js if you work with large amounts of data directly in IndexedDB or want a hosted sync and auth service. Choose SignalDB if your dataset fits in memory and you want rich queries, signal-based reactivity and sync with your existing backend.

SignalDB vs. PouchDB

PouchDB is an Apache project inspired by CouchDB. Its main strength is built-in, battle-tested two-way replication with CouchDB-compatible servers (CouchDB, Couchbase Sync Gateway and others), including revision-based conflict handling.

How SignalDB differs:

• Backend: PouchDB shines when your backend speaks the CouchDB replication protocol. SignalDB is backend-agnostic: REST, GraphQL, WebSockets or a BaaS such as Supabase or Firebase.
• Reactivity: PouchDB exposes a changes feed. SignalDB gives you reactive queries that integrate with your framework's signals.

Choose PouchDB if you run (or want to run) CouchDB. Choose SignalDB if you already have an API that does not speak the CouchDB protocol.

SignalDB vs. WatermelonDB

WatermelonDB is built for React and React Native apps with large datasets. It uses SQLite on mobile, loads data lazily, and is optimized to keep app launch fast with tens of thousands of records. Sync works through a protocol that you implement on your backend.

How SignalDB differs:

• Platform focus: WatermelonDB is mobile-first. SignalDB targets web apps today; proper React Native support is planned for SignalDB v2.
• Framework: WatermelonDB is optimized for React. SignalDB works with any framework that has signals.

Choose WatermelonDB if you build a React Native app with a lot of local data. Choose SignalDB if you build a web app with Angular, Vue, Solid, Svelte, React or another framework.

SignalDB vs. TinyBase

TinyBase is a reactive in-memory store organized as tables and values. It has persisters for many storage backends and synchronizers based on a CRDT (MergeableStore) that can sync between clients and servers over WebSockets, BroadcastChannel or custom transports.

How SignalDB differs:

• Data model: TinyBase stores tabular data (tables, rows, cells). SignalDB stores JSON documents in collections and queries them with MongoDB-like selectors.
• Sync model: TinyBase merges state with a CRDT, which works well for peer-to-peer and collaborative scenarios. SignalDB syncs with an authoritative backend through pull and push.

Choose TinyBase if you want CRDT-based sync or a tabular store with React hooks. Choose SignalDB if your server is the source of truth and you want document-style queries.

SignalDB vs. TanStack DB

TanStack DB extends TanStack Query with normalized collections, live queries and optimistic mutations. Data is loaded into collections from TanStack Query or from sync engines, and queried with a SQL-like query builder that supports joins. TanStack DB is currently in beta.

How SignalDB differs:

• Persistence and offline: SignalDB persists every collection locally (IndexedDB, OPFS, localStorage) and queues changes for sync, so the app works offline. TanStack DB focuses on the in-memory client store; data is loaded through collection types such as TanStack Query, ElectricSQL, PowerSync or RxDB, which are also responsible for persistence.
• Ecosystem: TanStack DB integrates tightly with TanStack Query. SignalDB is independent of your data-fetching library.

Choose TanStack DB if your app already uses TanStack Query and you want live queries with joins on top of it. Choose SignalDB if you need local persistence and offline support with your own backend.

Alternatives to RxDB

If you are looking for an RxDB alternative, the right choice depends on why RxDB does not fit:

• You want something smaller and signal-native for a web app: SignalDB.
• You want to work directly with IndexedDB and large datasets: Dexie.js.
• Your backend is CouchDB: PouchDB.
• You build a React Native app with lots of data: WatermelonDB.
• You want CRDT-based sync: TinyBase.
• You already use TanStack Query: TanStack DB.

Which Database Should You Choose?

Ask these questions in this order:

1. Which platform? Web only, or also React Native/Electron/Capacitor? Mobile-heavy apps narrow the list to RxDB and WatermelonDB.
2. Which backend? If the backend is fixed (CouchDB, a hosted service, your own REST/GraphQL API), choose a database that syncs with it without workarounds.
3. How much data per user? If it fits comfortably in memory, in-memory databases (SignalDB, TinyBase, TanStack DB) give you the fastest queries. For very large local datasets, prefer databases that query storage directly (Dexie.js, WatermelonDB, RxDB with an indexed storage).
4. How should data reach your UI? Signals (SignalDB), RxJS observables (RxDB), hooks (Dexie.js, TinyBase, TanStack DB) or observables with React helpers (WatermelonDB).
5. What can you pay for? All projects are open source, but some features (RxDB Pro, Dexie Cloud) are commercial.

When SignalDB Is the Right Choice

SignalDB fits best when:

• you build a web app with Angular, Vue, Solid, Svelte, React or another framework with signals;
• you want reactive queries that plug into your framework's own reactivity;
• the data of each user fits in memory (thousands to tens of thousands of documents);
• you have an existing backend (REST, GraphQL, WebSockets, Supabase, Firebase, Appwrite) and want to keep it;
• you want optimistic UI and offline support without adopting a new backend or a paid service.

Start with the Getting Started guide, or read more about offline-first, optimistic UI and JavaScript signals.

Frequently Asked Questions

What is the best local-first database for JavaScript?

There is no single best option. RxDB is the most feature-complete, Dexie.js is the most direct IndexedDB wrapper, PouchDB is best with CouchDB, WatermelonDB is built for React Native, TinyBase offers CRDT sync, TanStack DB extends TanStack Query, and SignalDB is a lightweight, signal-native choice for web apps with an existing backend.

What is the difference between RxDB and Dexie.js?

RxDB is a full database with schemas, replication and pluggable storages; one of its storages is built on Dexie.js. Dexie.js is a thin wrapper around IndexedDB with live queries and an optional sync service (Dexie Cloud).

What is the difference between RxDB and PouchDB?

Both are document databases that sync. PouchDB implements the CouchDB replication protocol and works best with CouchDB-compatible servers. RxDB has its own replication engine with plugins for many backends, including CouchDB.

Is SignalDB free?

Yes. SignalDB and all its adapters are open source under the MIT license.