# manifold-systems/manifold

Manifold is a Java compiler plugin, its features include Metaprogramming, Properties, Extension Methods, Operator Overloading, Templates, a Preprocessor, and more.

Repository: https://github.com/manifold-systems/manifold
Canonical: https://ross.abutalabs.com/products/manifold
Homepage: http://manifold.systems/
Language: Java
License: Apache-2.0
License Family: permissive
Topics: java, intellij, json, template-engine, reflection-framework, extension-methods, structural-typing, duck-typing, java-tooling, java-development, type-providers, metaprogramming, graphql, preprocessor, graphql-java, js-java-interoperability, android-studio, manifold, delegation, java-sql
Last push: 2026-08-19T15:02:27+00:00

## Health v2 (maintenance only)
Score: 76/100 (v2, computed 2026-09-03T02:39:23.370411+00:00)
- activity 98, release rhythm 35, longevity 100
- inputs: {"age_days": 3375, "days_push": 14, "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 2759, forks 133 (observed 2026-08-28T04:07:18.363524+00:00)

## What it is
Manifold is a Java compiler plugin that extends the Java language at compile time with features like extension methods, properties, operator overloading, templates, a preprocessor, and type-safe metaprogramming. It type-safely integrates schemas and DSLs such as SQL, JSON, YAML, XML, and GraphQL directly into Java code while remaining fully compatible with the JVM and existing Java tooling.

## Use cases
- add extension methods and operator overloading to Java
- query SQL with type-safe generated code
- consume JSON and YAML schemas type-safely in Java
- write type-safe GraphQL queries in Java
- use a preprocessor for conditional compilation in Java
- add properties and optional parameters to Java
- compose objects with true parts-based composition

## When to choose
- you want modern language features without leaving Java or the JVM
- you need type-safe access to SQL, JSON, YAML, XML, or GraphQL schemas
- you want to enhance an existing Java project incrementally
- you use IntelliJ IDEA or Android Studio and want IDE support for these features

## When to avoid
- your team prefers standard Java without compiler plugins
- you are wary of tools relying on internal compiler APIs
- you are not using a supported JDK (8-25) or an IntelliJ-based IDE
- you would rather switch to a full alternative language like Kotlin

## Facets
- artifact type: library
- maturity: active
- function: compiler, templating, serialization, parser, developer-tools, plugin-system
- domain: programming-languages, developer-tools, compilers, web-development, apis
- platform: jvm, editor-plugin, cross-platform
- tags: java-compiler-plugin, metaprogramming, extension-methods, operator-overloading, type-safe-sql, type-safe-, graphql, preprocessor, structural-typing, intellij-plugin, android-studio

## Member repositories
- manifold-systems/manifold (main) score 76

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:07:18.363524+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 2026-08-30T08:18:47.105178+00:00, confidence not recorded.
  - readme: https://github.com/manifold-systems/manifold (fetched 2026-08-28T04:07:18.363524+00:00, sha 5de4069a85fb)
  - homepage: http://manifold.systems/ (fetched 2026-08-29T09:56:50.274395+00:00, sha c609a9b6f660)
  - site_page: http://manifold.systems/faq.html (fetched 2026-08-29T09:56:50.277850+00:00, sha 7d484e8c51f3)
- Data as of 2026-08-30T08:39:29.467469+00:00.