# twitter/finagle

A fault tolerant, protocol-agnostic RPC system

Repository: https://github.com/twitter/finagle
Canonical: https://ross.abutalabs.com/products/finagle
Homepage: https://twitter.github.io/finagle
Language: Scala
License: Apache-2.0
License Family: permissive
Topics: rpc, distributed-systems, finagle, http, http2, thrift, mysql, memcached, redis, zipkin, java, scala
Last push: 2026-08-13T18:10:51+00:00

## Health v2 (maintenance only)
Score: 66/100 (v2, computed 2026-09-03T02:20:16.233290+00:00)
- activity 97, release rhythm 8, longevity 100
- inputs: {"age_days": 5797, "days_push": 20, "days_rel": null, "gap_med": null, "n_releases_24m": 0}
- flags: none
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 8864, forks 1431 (observed 2026-08-28T04:10:26.079356+00:00)

## What it is
Finagle is an extensible, fault-tolerant, protocol-agnostic RPC system for the JVM, written in Scala with idiomatic APIs for both Scala and Java. It provides uniform client and server APIs for protocols like HTTP/2, Thrift, MySQL, Redis, and Memcached, designed for high-concurrency distributed systems.

## Use cases
- build fault-tolerant RPC services on the JVM
- implement high-concurrency servers in Scala or Java
- add distributed tracing with Zipkin to service calls
- write protocol-agnostic clients and servers for Thrift or HTTP
- build resilient microservice backends with load balancing and retries
- connect to MySQL, Redis, or Memcached with managed clients

## When to choose
- you are building JVM-based distributed systems that need fault tolerance and load balancing
- you want uniform client/server APIs across multiple protocols
- you need battle-tested infrastructure proven at Twitter-scale production
- you want built-in Zipkin tracing and protocol extensibility

## When to avoid
- your stack is not on the JVM
- you want a lightweight HTTP framework for simple web apps
- you prefer simpler, more modern RPC frameworks like gRPC with less Scala-specific complexity
- you need stable semantic versioning, since Finagle does not follow semver

## Facets
- artifact type: library
- maturity: stable
- function: rpc, http-client, http-server, middleware, tracing, load-testing
- domain: microservices, backend, networking, developer-tools
- platform: jvm
- tags: fault-tolerance, thrift, http2, protocol-agnostic, high-concurrency, jvm, linux, macos

## Member repositories
- twitter/finagle (main) score 66

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:10:26.079356+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 2026-08-29T17:24:46.035769+00:00, confidence not recorded.
  - readme: https://github.com/twitter/finagle (fetched 2026-08-28T04:10:26.079356+00:00, sha 8ded9adf36db)
  - homepage: https://twitter.github.io/finagle (fetched 2026-08-29T08:24:57.757772+00:00, sha 4186b9aa15b3)
- Data as of 2026-08-30T08:39:29.467469+00:00.