# finagle/finch

Scala combinator library for building Finagle HTTP services

Repository: https://github.com/finagle/finch
Canonical: https://ross.abutalabs.com/products/finagle-finch
Homepage: https://finagle.github.io/finch
Language: Scala
License: Apache-2.0
License Family: permissive
Topics: finch, finagle, scala, http, json, circe, web, rest
Last push: 2025-09-14T13:16:16+00:00

## Health v2 (maintenance only)
Score: 42/100 (v2, computed 2026-09-02T17:46:02.011165+00:00)
- activity 42, release rhythm 8, longevity 100
- inputs: {"age_days": 4523, "days_push": 353, "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 1594, forks 218 (observed 2026-08-28T04:05:09.003227+00:00)

## What it is
Finch is a thin, purely functional combinator library for building composable HTTP APIs on top of Twitter's Finagle in Scala. Its core abstraction is Endpoint[A], with modules for JSON codecs (circe, argonaut), streaming (fs2), and testing support.

## Use cases
- build REST APIs in Scala on Finagle
- define type-safe HTTP endpoints with combinators
- serve JSON endpoints with automatic circe encoding
- build lightweight microservice HTTP servers on the JVM
- compose endpoint routing declaratively

## When to choose
- you have an existing Finagle-based Scala codebase
- you want a minimal, close-to-the-metal functional HTTP layer
- you need fine-grained control over Finagle primitives

## When to avoid
- starting a new project - Finch and Finagle are no longer maintained
- you want an actively maintained functional Scala HTTP server (use http4s instead)
- you need non-JVM platforms or non-Scala languages

## Facets
- artifact type: library
- maturity: abandoned
- function: web-framework, http-server, routing, serialization
- domain: web-development, backend, apis, developer-tools
- platform: jvm, cross-platform
- tags: finagle, scala, http-api, rest, circe, combinators, functional-programming, unmaintained

## Member repositories
- finagle/finch (main) score 42

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:05:09.003227+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 2026-08-30T03:54:11.485282+00:00, confidence not recorded.
  - readme: https://github.com/finagle/finch (fetched 2026-08-28T04:05:09.003227+00:00, sha 1ff3fa7e65e2)
  - homepage: https://finagle.github.io/finch (fetched 2026-08-29T11:24:55.665770+00:00, sha 413eed9acdce)
- Data as of 2026-08-30T08:39:29.467469+00:00.