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Isar
What it is
Isar is a free, open-source NoSQL database for Flutter apps, including apps that need local data access when a network connection is unavailable. It runs on Android, iOS, and the web, with minimal setup and no configuration or boilerplate. A database can hold hundreds of thousands of records and query them asynchronously. Developers can use composite and multi-entry indexes, query modifiers, JSON support, and built-in full-text search. Queries are statically typed and checked at compile time. Isar handles transactions automatically and rolls changes back if an error occurs; it also supports parallel query operations and multiple isolates. The software is Apache licensed and listed as free forever at no cost. There are platform-specific limits. On VM platforms, prefix where-clauses can use only the first 1024 bytes of a string, and objects are limited to 16 MB. On the web, synchronous methods are unsupported, as are the splitWords() and matches() filters and NaN. Isar adds about 1–1.5 MB to an app download, while Isar Web adds only a few KB.
For and against
For
- Free and Apache licensed.
- Supports Android, iOS, and web.
- Provides full-text search and JSON support.
- Queries are statically typed and compile-time checked.
- Includes automatic transactions and rollback on errors.
Against
- VM objects are limited to 16 MB.
- VM prefix queries use only 1024 string bytes.
- Web synchronous methods are unsupported.
- Adds about 1–1.5 MB to app downloads.
The verdict
Isar pairs local NoSQL storage with typed queries and built-in indexing and search. Its platform-specific restrictions and app-size impact are worth checking before choosing it for a project.
Who it suits
It suits Flutter developers who want local database access, including when offline. Developers should check the VM and web constraints for the platform and query behavior they need.
Plans and prices
Open source
open source · Apache licensed
Read 30 Sep 2026 · isar.dev
On the record
- App size
- Isar adds about 1–1.5 MB to an app download, while Isar Web adds only a few KB.isar.dev · read 30 Sep 2026
- Concurrency
- Isar provides parallel query operations and multi-isolate support out of the box.isar.dev · read 30 Sep 2026
- Full-text search
- Isar has built-in full-text search using a multi-entry index.isar.dev · read 30 Sep 2026
- Indexes
- Isar supports composite and multi-entry indexes, query modifiers, and JSON support.isar.dev · read 30 Sep 2026
- License
- Isar is open source, free forever, and Apache licensed.isar.dev · read 30 Sep 2026
- Product
- Isar is a super-fast cross-platform NoSQL database for Flutter.isar.dev · read 30 Sep 2026
- Scalability
- Isar can store hundreds of thousands of records in one NoSQL database and query them efficiently and asynchronously.isar.dev · read 30 Sep 2026
- Setup
- Isar provides minimal setup with no configuration or boilerplate.isar.dev · read 30 Sep 2026
- Static typing
- Isar queries are statically typed and checked at compile time.isar.dev · read 30 Sep 2026
- Support
- The documentation asks users to open an issue or submit a pull request for documentation errors.isar.dev · read 30 Sep 2026
- Target users
- Isar is designed for Flutter developers who need local data access when a network connection is unavailable.isar.dev · read 30 Sep 2026
- Transactions
- Isar is ACID compliant, handles transactions automatically, and rolls back changes when an error occurs.isar.dev · read 30 Sep 2026
- VM limit
- On VM platforms, only the first 1024 bytes of a string can be used for a prefix where-clause and objects can be at most 16MB.isar.dev · read 30 Sep 2026
- Web limits
- On Web, synchronous methods are unsupported, splitWords() and matches() filters are not implemented, and NaN is unsupported.isar.dev · read 30 Sep 2026
