# error-or/error-or

A simple, fluent discriminated union of an error or a result.

Repository: https://github.com/error-or/error-or
Canonical: https://ross.abutalabs.com/products/error-or
Language: C#
License: MIT
License Family: permissive
Last push: 2026-08-21T04:25:47+00:00

## Health v2 (maintenance only)
Score: 94/100 (v2, computed 2026-09-02T17:46:02.011165+00:00)
- activity 98, release rhythm 84, longevity 100
- inputs: {"age_days": 1555, "days_push": 12, "days_rel": 110, "gap_med": 5, "n_releases_24m": 2}
- flags: none
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 2081, forks 115 (observed 2026-08-28T04:06:11.605239+00:00)

## What it is
ErrorOr is a C# library providing a fluent discriminated union type of either an error or a result value, letting developers replace exception-based control flow with explicit error handling. It supports multiple errors, implicit conversions, and functional methods like Match, Switch, and Then for chaining.

## Use cases
- replace exceptions with result types in C#
- return multiple errors from a service method
- chain operations with fluent error handling
- implement railway-oriented programming in .NET
- model success-or-failure API responses

## When to choose
- you write C#/.NET code and want explicit, exception-free error handling
- you need to propagate multiple errors through a fluent pipeline
- you want Match/Switch/Then combinators for result handling

## When to avoid
- your codebase relies on exception-based flow control
- you need a language-level union type rather than a library abstraction
- you work outside the .NET ecosystem

## Facets
- artifact type: library
- maturity: active
- function: error-handling, serialization
- domain: developer-tools, backend, web-development
- platform: dotnet, cross-platform
- tags: result-type, discriminated-union, functional-programming, csharp, nuget, railway-oriented-programming

## Member repositories
- error-or/error-or (main) score 94

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:06:11.605239+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 2026-08-30T02:55:57.383751+00:00, confidence not recorded.
  - readme: https://github.com/error-or/error-or (fetched 2026-08-28T04:06:11.605239+00:00, sha fa424db1a8f5)
- Data as of 2026-08-30T08:39:29.467469+00:00.