# twitter/effectivescala

Twitter's Effective Scala Guide

Repository: https://github.com/twitter/effectivescala
Canonical: https://ross.abutalabs.com/products/effectivescala
Homepage: https://twitter.github.io/effectivescala
Language: HTML
License: NOASSERTION
License Family: other
Last push: 2023-04-10T11:47:00+00:00

## Health v2 (maintenance only)
Score: 32/100 (v2, computed 2026-09-02T17:46:02.011165+00:00)
- activity 0, release rhythm 35, longevity 100
- inputs: {"age_days": 5328, "days_push": 1241, "days_rel": null, "gap_med": null, "n_releases_24m": 0}
- flags: no_releases, no_license
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 2231, forks 610 (observed 2026-08-28T04:06:29.098653+00:00)

## What it is
Twitter's Effective Scala guide, a document distilling Twitter's experience and best practices for writing Scala in production, covering formatting, types, collections, concurrency, functional and object-oriented programming, and error handling. The repository contains the markdown source and build tooling (PEG markdown and groff) used to render and publish the guide to GitHub Pages.

## Use cases
- learn Scala best practices from Twitter's production experience
- find recommended Scala style and formatting conventions
- understand how to use Scala futures and concurrency effectively
- decide which Scala features to embrace or avoid
- improve functional programming style in Scala
- onboard engineers to idiomatic Scala for high-volume services

## When to choose
- you want concise, battle-tested guidance on writing effective Scala
- your team builds high-volume distributed services in Scala
- you need a reference for Scala idioms like Options, pattern matching, and case classes as algebraic data types
- you want a style guide to align a Scala codebase

## When to avoid
- you need a tutorial for learning Scala from scratch
- you need up-to-date coverage of the latest Scala 3 features
- you want runnable code or a tool rather than a written guide
- you need an officially maintained specification rather than opinionated advice

## Facets
- artifact type: learning-resource
- maturity: maintenance
- function: documentation
- domain: programming-languages, developer-tools, tutorials
- platform: cross-platform
- tags: scala, style-guide, best-practices, programming-guide, twitter, functional-programming, concurrency, markdown-document

## Member repositories
- twitter/effectivescala (main) score 32

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:06:29.098653+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 2026-08-30T02:44:36.837438+00:00, confidence not recorded.
  - readme: https://github.com/twitter/effectivescala (fetched 2026-08-28T04:06:29.098653+00:00, sha c0058a88c0c3)
  - homepage: https://twitter.github.io/effectivescala (fetched 2026-08-29T10:25:03.234666+00:00, sha 6ec6f8481f2e)
- Data as of 2026-08-30T08:39:29.467469+00:00.