rust-lang/hashbrown

Health v2 · maintenance only

Adoption not part of the score

2983 stars · 357 forks observed · 2026-08-28

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

hashbrown is a Rust port of Google's SwissTable hash map, serving as a drop-in replacement for the standard library's HashMap and HashSet. It is the implementation adopted by Rust's std HashMap and can also be used directly, including in no_std environments with an allocator.

Use cases

• replace std HashMap with a faster hash map in Rust
• use a hash map in a no_std embedded or kernel environment
• reduce memory overhead of hash tables in Rust
• get faster hash set lookups with SIMD
• choose a custom or faster default hasher for hash maps

When to choose

• you need a high-performance HashMap/HashSet in Rust, roughly 2x faster than the old std implementation
• you are targeting no_std environments like embedded systems or kernels with a global allocator
• you want lower per-entry memory overhead (1 byte vs 8)
• you need serde or rayon support for hash containers

When to avoid

• you need strong HashDoS resistance by default, since foldhash is weaker than SipHash
• you just use std HashMap and don't need no_std or custom hasher control
• you rely on the deprecated RawEntry API as a primary feature

Facets

library · maturity stable

caching developer-tools performance developer-tools rust embedded cross-platform hashmap swisstable hash-table no-std simd data-structures algorithms

Member repositories

For agents

markdown · JSON · MCP: product_card(name="rust-lang/hashbrown")