# vstakhov/libucl

Universal configuration library parser

Repository: https://github.com/vstakhov/libucl
Canonical: https://ross.abutalabs.com/products/libucl
Language: C
License: BSD-2-Clause
License Family: permissive
Last push: 2026-08-24T18:55:16+00:00

## Health v2 (maintenance only)
Score: 85/100 (v2, computed 2026-09-03T02:20:16.233290+00:00)
- activity 99, release rhythm 59, longevity 100
- inputs: {"age_days": 4710, "days_push": 9, "days_rel": 197, "gap_med": 69, "n_releases_24m": 2}
- flags: none
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 1743, forks 160 (observed 2026-08-28T04:05:30.468747+00:00)

## What it is
A C library for parsing and emitting UCL (Universal Configuration Language), an nginx-inspired configuration format fully compatible with JSON. It also supports reading and writing JSON and Messagepack, reading S-expressions, and limited YAML output.

## Use cases
- parse nginx-style configuration files in C
- read and write JSON from a C application
- convert configuration between JSON, Messagepack, and UCL formats
- write human-friendly config files with comments, macros, and variables
- validate configuration files against a schema
- parse config files with includes and multiline strings

## When to choose
- you need a fast, lightweight C configuration parser with JSON compatibility
- you want nginx-like config syntax with comments, macros, and variables
- you need to interoperate between JSON, Messagepack, and a friendlier config format
- you are parsing trusted, administrator-controlled configuration files

## When to avoid
- you need to parse untrusted or adversarial input without disabling macros, includes, and URL fetching
- you need full YAML reading support (only limited YAML writing is available)
- you need a configuration library in a language other than C or with bindings already provided elsewhere

## Facets
- artifact type: library
- maturity: stable
- function: parser, serialization, configuration-management, yaml
- domain: developer-tools, parsers, apis
- platform: cross-platform, c, windows, bsd
- tags: configuration-language, ucl, nginx-style-config, messagepack, s-expressions, config-parser, configuration, linux, macos

## Member repositories
- vstakhov/libucl (main) score 85

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:05:30.468747+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 2026-08-30T03:29:44.996764+00:00, confidence not recorded.
  - readme: https://github.com/vstakhov/libucl (fetched 2026-08-28T04:05:30.468747+00:00, sha cd7ba54ad9b5)
- Data as of 2026-08-30T08:39:29.467469+00:00.