fjall-rs/fjall

Health v2 · maintenance only

Adoption not part of the score

2291 stars · 117 forks observed · 2026-08-28

What it is AI-extracted, prompt v1, taxonomy v1, 2026-08-30, confidence not recorded

Fjall is a log-structured (LSM-tree-based), embeddable key-value storage engine written in 100% safe Rust, similar in spirit to RocksDB. It offers a thread-safe BTreeMap-like API with multiple keyspaces, range/prefix iteration, optional serializable transactions, built-in LZ4 compression, and key-value separation for large blobs.

Use cases

• embed a key-value store in a Rust application
• replace RocksDB or LevelDB with a pure-Rust storage engine
• store large blobs with key-value separation
• build a database or index on top of an LSM-tree engine
• run range and prefix scans with forward and reverse iteration
• use column-family-like keyspaces with atomic cross-keyspace writes
• need serializable transactions in an embedded store

When to choose

• you need an embeddable, serverless key-value engine in Rust
• you want RocksDB-like LSM performance without C++ dependencies
• you need multiple keyspaces, transactions, or blob separation in-process

When to avoid

• you need a standalone database server or network API
• you need a relational database, SQL, or query language
• your project is not in Rust

Facets

library · maturity active

database serialization caching databases developer-tools backend rust cross-platform lsm-tree key-value-store embedded-database storage-engine keyspace transactions compression

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