# awslabs/shuttle

Shuttle is a library for testing concurrent Rust code

Repository: https://github.com/awslabs/shuttle
Canonical: https://ross.abutalabs.com/products/awslabs-shuttle
Language: Rust
License: Apache-2.0
License Family: permissive
Last push: 2026-09-02T10:24:25+00:00

## Health v2 (maintenance only)
Score: 91/100 (v2, computed 2026-09-03T02:20:16.233290+00:00)
- activity 100, release rhythm 74, longevity 100
- inputs: {"age_days": 2011, "days_push": 0, "days_rel": 13, "gap_med": 122, "n_releases_24m": 6}
- flags: none
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 1050, forks 59 (observed 2026-09-03T02:15:09.459251+00:00)

## What it is
Shuttle is a Rust library for testing concurrent code using randomized concurrency scheduling techniques with probabilistic bug-finding guarantees. It provides drop-in wrappers for std::sync, tokio, and rand so tests can deterministically reproduce race conditions.

## Use cases
- find race conditions in concurrent Rust code
- reproduce flaky multithreaded tests deterministically
- test async tokio code for scheduling bugs
- randomly stress-test thread synchronization primitives
- debug intermittent concurrency failures in CI

## When to choose
- you write concurrent or async Rust and need reliable detection of race conditions
- you want deterministic reproduction of nondeterministic concurrency bugs
- you need a randomized alternative to exhaustive checkers like Loom for larger programs

## When to avoid
- you need exhaustive formal verification of all interleavings
- your code is single-threaded with no concurrency
- you are testing concurrency in languages other than Rust

## Facets
- artifact type: library
- maturity: active
- function: testing, concurrency, fuzzing
- domain: testing, developer-tools
- platform: rust, cross-platform
- tags: concurrency-testing, randomized-scheduling, race-condition-detection, async-testing, rust, concurrency

## Member repositories
- awslabs/shuttle (main) score 91

## Provenance
- Observed fields: from GitHub, fetched 2026-09-03T02:15:09.459251+00:00.
- Health v2: computed from the inputs above; adoption is never an input.
- Inferred fields (summary, facets, guidance): AI-extracted, prompt v1, taxonomy v1, on 2026-08-30T07:01:56.763019+00:00, confidence not recorded.
  - readme: https://github.com/awslabs/shuttle (fetched 2026-09-03T02:15:09.459251+00:00, sha 596bee125aac)
  - registry_crates: https://crates.io/api/v1/crates/shuttle (fetched 2026-08-29T13:02:34.905447+00:00, sha 62f423193ca7)
- Data as of 2026-08-30T08:39:29.467469+00:00.