# mvel/mvel

MVEL (MVFLEX Expression Language)

Repository: https://github.com/mvel/mvel
Canonical: https://ross.abutalabs.com/products/mvel
Homepage: http://mvel.documentnode.com/
Language: Java
License: Apache-2.0
License Family: permissive
Last push: 2026-08-26T09:32:49+00:00

## Health v2 (maintenance only)
Score: 77/100 (v2, computed 2026-09-03T02:20:16.233290+00:00)
- activity 99, release rhythm 35, longevity 100
- inputs: {"age_days": 5587, "days_push": 7, "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 1203, forks 318 (observed 2026-08-28T04:03:58.612586+00:00)

## What it is
MVEL (MVFLEX Expression Language) is an embeddable expression language and runtime for the Java platform, with MVEL3 transpiling expressions to Java source, compiling them in-memory via javac, and executing the resulting bytecode. It also serves as a templating language and is commonly embedded in applications like rule engines for evaluating dynamic expressions.

## Use cases
- evaluate dynamic expressions in a Java application
- embed a scripting/expression language in a rule engine
- compile user-supplied expressions to JVM bytecode
- evaluate expressions against POJO properties or maps
- render templates with embedded expressions
- build configurable business rules with expression conditions

## When to choose
- you need a Java-syntax-compatible expression language embedded in a JVM application
- you want expressions compiled to bytecode rather than interpreted
- you need templating plus expression evaluation in one library

## When to avoid
- you need a stable, battle-tested release (MVEL3 is alpha with changing APIs)
- you will evaluate expressions from untrusted sources (expressions can execute arbitrary JVM operations)
- you need a general-purpose scripting language rather than an expression language

## Facets
- artifact type: library
- maturity: experimental
- function: parser, interpreter, compiler, templating
- domain: programming-languages, developer-tools, parsers
- platform: jvm, cross-platform
- tags: expression-language, expression-evaluation, rule-engines, dynamic-typing, transpilation

## Member repositories
- mvel/mvel (main) score 77

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:03:58.612586+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 2026-08-30T06:20:31.284246+00:00, confidence not recorded.
  - readme: https://github.com/mvel/mvel (fetched 2026-08-28T04:03:58.612586+00:00, sha f8c4d8298953)
  - homepage: http://mvel.documentnode.com/ (fetched 2026-08-29T12:27:27.204063+00:00, sha e9ab4636f621)
- Data as of 2026-08-30T08:39:29.467469+00:00.