# dtolnay/anyhow

Flexible concrete Error type built on std::error::Error

Repository: https://github.com/dtolnay/anyhow
Canonical: https://ross.abutalabs.com/products/anyhow
Language: Rust
License: Apache-2.0
License Family: permissive
Last push: 2026-08-22T02:43:42+00:00

## Health v2 (maintenance only)
Score: 97/100 (v2, computed 2026-09-03T02:20:16.233290+00:00)
- activity 99, release rhythm 93, longevity 100
- inputs: {"age_days": 2524, "days_push": 11, "days_rel": 46, "gap_med": 23, "n_releases_24m": 18}
- flags: none
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 6631, forks 221 (observed 2026-08-28T04:09:45.816144+00:00)

## What it is
A Rust library providing anyhow::Error, a trait-object-based concrete error type for idiomatic error handling in applications. It supports easy error propagation with ?, context attachment, downcasting, and optional backtrace capture.

## Use cases
- handle errors in a Rust application without defining custom error types
- propagate errors with the ? operator across fallible functions
- add human-readable context to low-level errors like IO failures
- downcast errors to underlying concrete error types
- capture and print backtraces for errors
- simplify error handling in application code rather than library code

## When to choose
- you are building a Rust application and want ergonomic error handling
- you want a single concrete error type instead of custom error enums
- you need to attach context messages to errors as they bubble up
- you want backtrace support with minimal boilerplate

## When to avoid
- you are writing a public library where callers need to match on specific error variants
- you need structured, typed error enums for programmatic error handling
- you need no_std or embedded support

## Facets
- artifact type: library
- maturity: stable
- function: error-handling
- domain: developer-tools, programming-languages
- platform: rust
- tags: error-type, rust-library, result, backtrace, error-context

## Member repositories
- dtolnay/anyhow (main) score 97

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:09:45.816144+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 2026-08-29T17:43:13.612695+00:00, confidence not recorded.
  - readme: https://github.com/dtolnay/anyhow (fetched 2026-08-28T04:09:45.816144+00:00, sha fc09a1e1cd57)
  - registry_crates: https://crates.io/api/v1/crates/anyhow (fetched 2026-08-29T08:39:32.778818+00:00, sha 5605a11feef5)
- Data as of 2026-08-30T08:39:29.467469+00:00.