hidane
A Firestore emulator without Java, in one Rust binary
FreeOpen SourceDBTesting213 impressions#41 this week2 comments+1 today
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>log in to commentUpdate for launch week: hidane v0.4.0 is out today. Firestore-triggered Cloud Functions now fire under hidane exec -- firebase emulators:start, v1 and v2 (withAuthContext too). The events are recorded from the official emulator and replayed in CI, and functions receive the same data end to end. The Go, Python and Java server SDKs are now verified against both emulators as well, and the test suite replays 20,224 answers recorded from the official emulator. Release notes: https://github.com/hidane-dev/hidane/releases/tag/v0.4.0 If your Firestore tests get a different answer from hidane than from the official emulator, please open an issue. That is the most useful feedback, and I'm here all week to answer questions.
Hey everyone 👋 I'm the maker. We built hidane: A Firestore emulator without Java, in one Rust binary. I'd love your honest feedback, and I'm here all week to answer questions!
hidane (火種, "the seed of fire") replaces the official Cloud Firestore emulator with a single Rust binary. No JDK: firebase-tools 15 made Java 21 a requirement, and hidane needs none.
- Same wire protocols: gRPC, REST and WebChannel on one port, so the Admin SDK, the Google Cloud libraries for Node, Go, Python and Java, the web SDK (Node, Lite and the browser) and Flutter Web connect unchanged.
- Security Rules: decided as the official emulator decides them, with its denial messages, coverage report and
debug()output; the Emulator UI's Requests tab works. - Runs under firebase-tools, Cloud Functions included:
hidane exec -- firebase emulators:start. Since v0.4, Firestore-triggered functions, v1 and v2, fire on the same writes with the same data as with the official emulator. - Tested against the official emulator: hidane's test suite replays 20,224 answers recorded from it, REST byte for byte, and firebase-js-sdk's own browser test suite passes on hidane as on the official emulator (1,183 tests). A parity table on hidane.dev counts what is compared. Its bugs are not reproduced, and every difference is documented.
- Fast: 5.5 ms to open its port and 7.4 MiB idle, against 0.74 s and 95 MiB; writes stay flat with listeners attached (measured on different machines; a same-machine run is planned).
- Exports in the official format, both ways.
Install with curl -fsSL https://hidane.dev/install.sh | sh, Homebrew, npm, cargo or Docker. Open source, MIT OR Apache-2.0.
Unofficial; not affiliated with Google. Firebase and Cloud Firestore are trademarks of Google LLC.
hidane is a Rust-based Firestore emulator that runs without Java.
- for
- Developers needing a local Firestore emulator without a JDK.
- pricing
- open source
- license
- Apache-2.0
- v0.1.0hidane 0.1.04 days ago
Key features
- Single binary, no JVM — Runs as one Rust executable, eliminating the need for a Java runtime.
- Millisecond startup — Starts in ~5.5 ms and uses only 7.4 MiB of memory.
- Full protocol support — Implements gRPC, REST and WebChannel on a single port for all SDKs.
- Export/Import compatibility — Exports and imports data in the official emulator format.
- Parity testing — Validated against 28 recorded fixtures to match official emulator responses.
- Multiple install methods — Available via curl script, Homebrew, npm, cargo, Docker and binary releases.
Use cases
- Fast local development of Firestore-backed apps without installing Java
- CI pipelines that need quick Firestore emulation
- Testing Firestore security rules once v0.2 is released
- Running firebase-tools emulators:start with hidane as a drop-in replacement
- Benchmarking write performance at large document counts
hidane vs alternatives
 hidane |  Firebase |  Supabase |  Appwrite |  Convex | |
|---|---|---|---|---|---|
| Best for | Java-free Firestore emulation | Google-provided Firestore emulation | Postgres-based backend platform | Open-source full-stack backend | Reactive TypeScript backend |
| Pricing | Open source | Subscription | Subscription | Subscription | Subscription |
| DevHunt upvotes | 2 | 0 | 0 | 0 | 0 |
| Launched | Oct 2026 | — | — | — | — |
- hidane vs Firebase: Official Firebase emulator requires Java 21, hidane is Java-free and faster to start
- hidane vs Supabase: Supabase provides a full Postgres backend, not a Firestore-compatible emulator
- hidane vs Appwrite: Appwrite offers a complete backend suite, whereas hidane only emulates Firestore without Java
- hidane vs Convex: Convex is a reactive backend database, not a drop-in Firestore emulator
hidane FAQ
Does hidane require Java?+
No, it runs as a single Rust binary and does not need a JDK.
How does startup time compare to the official emulator?+
hidane starts in about 5.5 ms and uses 7.4 MiB, versus 0.74 s and 95 MiB for the official emulator.
Are security rules enforced?+
In v0.1 every request is allowed; security-rule enforcement is planned for v0.2.
How can I install hidane?+
Install via curl script, Homebrew, npm, cargo, Docker, or direct binary download.
Is hidane compatible with existing Firestore SDKs?+
Yes, it supports the same gRPC, REST and WebChannel protocols and has been verified with several Node and browser SDKs.
Summarized by DevHunt from hidane.dev · Oct 12, 2026. Details may change; check the official site.
