# facebook/fatal

Fatal is a library for fast prototyping software in modern C++. It provides facilities to enhance the expressive power of C++. The library is heavily based on template meta-programming, while keeping the complexity under-the-hood.

Repository: https://github.com/facebook/fatal
Canonical: https://ross.abutalabs.com/products/fatal
Homepage: https://www.facebook.com/groups/libfatal/
Language: C++
License: NOASSERTION
License Family: other
Last push: 2026-08-24T15:05:13+00:00

## Health v2 (maintenance only)
Score: 95/100 (v2, computed 2026-09-03T02:39:23.370411+00:00)
- activity 99, release rhythm 87, longevity 100
- inputs: {"age_days": 4376, "days_push": 9, "days_rel": 9, "gap_med": 7, "n_releases_24m": 100}
- flags: no_license
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 1017, forks 159 (observed 2026-08-28T04:03:14.666955+00:00)

## What it is
Fatal (Facebook Template Library) is a header-only C++14 library for fast software prototyping, built heavily on template meta-programming to enhance C++'s expressive power. It also includes lessons and demos teaching meta-programming from beginner levels.

## Use cases
- write template metaprograms in C++ without the boilerplate
- learn C++ template meta-programming from beginner lessons
- add compile-time utilities to a C++14 project
- prototype software quickly in modern C++
- benchmark and unit test metaprogramming code

## When to choose
- you want a dependency-free, header-only C++ metaprogramming toolkit
- you're on a C++14-compliant Clang or GCC compiler
- you want to learn template meta-programming with guided examples

## When to avoid
- your toolchain doesn't support C++14
- you need a stable API - master receives breaking changes without notice
- you prefer runtime libraries over compile-time abstractions

## Facets
- artifact type: library
- maturity: maintenance
- function: developer-tools, type-system, benchmarking, testing
- domain: developer-tools, programming-languages
- platform: cpp, cross-platform, windows
- tags: template-metaprogramming, header-only, c++14, compile-time, learning-resource, algorithms, linux, macos

## Member repositories
- facebook/fatal (main) score 95

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:03:14.666955+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 2026-08-30T07:11:11.885931+00:00, confidence not recorded.
  - readme: https://github.com/facebook/fatal (fetched 2026-08-28T04:03:14.666955+00:00, sha 69e63290df14)
- Data as of 2026-08-30T08:39:29.467469+00:00.