# kevin-montrose/Jil

Fast .NET JSON (De)Serializer, Built On Sigil

Repository: https://github.com/kevin-montrose/Jil
Canonical: https://ross.abutalabs.com/products/jil
Language: C#
License: MIT
License Family: permissive
Last push: 2024-04-17T22:44:16+00:00

## Health v2 (maintenance only)
Score: 32/100 (v2, computed 2026-09-03T02:20:16.233290+00:00)
- activity 0, release rhythm 35, longevity 100
- inputs: {"age_days": 4727, "days_push": 868, "days_rel": null, "gap_med": null, "n_releases_24m": 0}
- flags: no_releases
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 2140, forks 249 (observed 2026-08-28T04:06:18.356611+00:00)

## What it is
Jil is a fast JSON serializer and deserializer for .NET, built on Sigil to emit highly optimized code at runtime. It supports both static typed and dynamic (DLR-based) serialization and deserialization.

## Use cases
- serialize c# objects to  fast
- deserialize  into typed .NET classes
- high performance  parsing in asp.net
- serialize dynamic or expandoobject types to
- reduce  serialization overhead in hot paths

## When to choose
- you need maximum JSON throughput in .NET and can tolerate warm-up cost
- you want a lightweight serializer without heavy dependencies
- you need dynamic JSON handling with DLR support

## When to avoid
- you need case-insensitive deserialization by default
- you want a batteries-included serializer with rich attribute-based customization
- you need actively developed features rather than maintenance

## Facets
- artifact type: library
- maturity: maintenance
- function: serialization
- domain: developer-tools, backend, apis
- platform: dotnet, cross-platform
- tags: -serializer, sigil, performance, csharp

## Member repositories
- kevin-montrose/Jil (main) score 32

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:06:18.356611+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 2026-08-30T02:51:28.765848+00:00, confidence not recorded.
  - readme: https://github.com/kevin-montrose/Jil (fetched 2026-08-28T04:06:18.356611+00:00, sha 9d5aa921d288)
- Data as of 2026-08-30T08:39:29.467469+00:00.