# App-vNext/Polly

Polly is a .NET resilience and transient-fault-handling library that allows developers to express policies such as Retry, Circuit Breaker, Timeout, Bulkhead Isolation, and Fallback in a fluent and thread-safe manner. From version 6.0.1, Polly targets .NET Standard 1.1 and 2.0+.

Repository: https://github.com/App-vNext/Polly
Canonical: https://ross.abutalabs.com/products/polly
Homepage: https://www.thepollyproject.org
Language: C#
License: BSD-3-Clause
License Family: permissive
Topics: circuit-breaker, circuit-breaker-pattern, resilience, resiliency-patterns, retry-strategies, dotnet, fault-handler, transient-fault-handling
Last push: 2026-08-23T10:35:37+00:00

## Health v2 (maintenance only)
Score: 91/100 (v2, computed 2026-09-03T02:20:16.233290+00:00)
- activity 99, release rhythm 75, longevity 100
- inputs: {"age_days": 4868, "days_push": 10, "days_rel": 86, "gap_med": 47, "n_releases_24m": 12}
- flags: none
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 14230, forks 1285 (observed 2026-08-28T04:11:06.484000+00:00)

## What it is
Polly is a .NET resilience and transient-fault-handling library that lets developers express resilience strategies such as Retry, Circuit Breaker, Hedging, Timeout, Rate Limiter, and Fallback in a fluent, thread-safe manner. It is a zero-dependency, lightweight library targeting .NET Standard, usable anywhere .NET runs.

## Use cases
- retry failed HTTP calls with exponential backoff
- add circuit breaker to microservice calls
- wrap Entity Framework calls with transient fault handling
- apply timeout and bulkhead isolation to protect under-load systems
- add fallback behavior when external services fail
- rate-limit outgoing requests to a dependency

## When to choose
- building fault-tolerant .NET applications that call external services or cloud APIs
- needing a comprehensive, fluent resilience framework for .NET similar to Hystrix
- wanting a zero-dependency library that works across .NET Standard targets

## When to avoid
- working outside the .NET ecosystem
- needing resilience for a platform with native alternatives like Java's Resilience4j
- requiring chaos engineering as the primary goal (Simmy is a separate contrib)

## Facets
- artifact type: library
- maturity: stable
- function: middleware, rate-limiting, caching, error-handling, concurrency
- domain: developer-tools, backend, microservices, cloud-computing
- platform: dotnet, cross-platform
- tags: resilience, circuit-breaker, retry, transient-fault-handling, timeout, bulkhead-isolation, hedging, fallback, fault-tolerance

## Member repositories
- App-vNext/Polly (main) score 91

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:11:06.484000+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 2026-08-29T17:12:43.263541+00:00, confidence not recorded.
  - readme: https://github.com/App-vNext/Polly (fetched 2026-08-28T04:11:06.484000+00:00, sha 24a1cbc96ffa)
  - homepage: https://www.thepollyproject.org (fetched 2026-08-29T08:06:19.991439+00:00, sha 8d536d817013)
  - site_page: https://thepollyproject.org/about.html (fetched 2026-08-29T08:06:20.000774+00:00, sha e2eeb58f1802)
- Data as of 2026-08-30T08:39:29.467469+00:00.