Transmute Playground
Free online DataWeave-compatible transformation editor
A free, browser-based playground for DataWeave-compatibletransformations — powered by Transmute, a DataWeave-compatible engine written entirely in Java. Test map, filter, reduce, groupBy, mapObject and more live as you type, across JSON, XML, CSV, and YAML. It's the exact engine that powers API Modernizer's Mule-to-Spring-Boot conversions in production — no signup required.
Playground features
Live as you type
Debounced, cancellable execution — see your transformation output update as you edit.
Multi-format
JSON, XML, CSV, YAML, and plain text input and output.
Full DSL reference
Built-in guide covering every function, operator, and pattern.
Power. Speed. Purity.
Not a demo engine with a production engine bolted on later — the same DSL runtime, running here, that converts real Mule applications.
Power
The full DataWeave surface: map, filter, reduce, groupBy, mapObject, scatter-gather, error handlers, using() scoping, format strings, type coercions. Nothing held back for the paid product.
Fast performance
Every run reports its real execution time in milliseconds, right in the output panel — not a marketing number, the actual measurement from that keystroke.
Java-based purity
Built and compiled as a standard Java library, executing natively on the JVM — the same runtime your Spring Boot services already run on. No foreign process to shell out to, no separate interpreter to keep in sync.