About this FEEL evaluator
feel.dmn.tools is a free, vendor-neutral tester for DMN FEEL expressions. It is built and maintained by Nvaria GmbH, a Swiss consultancy for business process and decision automation.
The evaluator
Expressions are evaluated by the Impulse FEEL interpreter: a FEEL implementation written in Java based on the GraalVM Truffle language implementation framework and compiled to WebAssembly with GraalVM Web Image.
The module uses WebAssembly garbage collection and the exception-handling proposal, so it needs a current browser: Chrome or Edge 137+, Firefox 131+, Safari 18.4+. Older browsers report that the evaluator cannot run rather than failing silently.
What is covered, and what is not
FEEL as defined by OMG DMN 1.6 Beta 1, including all 88 built-in functions and the business-friendly B-FEEL dialect of chapter 11.
Vendor neutrality
FEEL is an OMG standard, so expressions tested here run unchanged on any conformant DMN engine, however other interpreters may not fully implement DMN FEEL 1.6b1.
Privacy
Nothing is sent anywhere. The interpreter runs in your browser as a WebAssembly module; expressions and context data never leave your machine. There is no account, no tracking cookie and no usage limit.
Who builds it
Nvaria GmbH Switzerland — business process and decision automation consulting and software development, with a practice built around BPMN and DMN engines.