available in alpha preview

Melbi: The Embedded Language for Safe, Dynamic Logic.

Give your users or power systems the ability to define conditional behavior, data transformations, and automation rules—without ever modifying your application's source code.

Why Choose Melbi?

Sandboxed & Restricted

Ensure runtime safety with its sandboxed environment. Perfect for tasks like defining email filters or user-defined triggers.

Type Safe & Fast

Melbi is built to be type-safe and expression-focused, with arena-based execution for performance comparable to native code.

Flexible & Embeddable

Designed to be effortlessly embeddable, Melbi separates dynamic user logic from your main codebase.

Write Elegant Code

A simple example of A/B testing business logic shows off Melbi's clean, expression-focused syntax.

Highly Readable

Melbi's readable syntax lowers the barrier for users to define powerful custom logic.

Minimal Boilerplate

Focus on logic, not configuration. Melbi infers types wherever possible.

main.melbi
// A/B test rollout decision
user.country == "US" and user.age >= 18 and
Hash.ConsistentHash(user.id, 100) < rollout
where {
    rollout = rollouts[feature_name] otherwise 0
}
UTF-8 Ln 5, Col 2

Ready to Dive Deeper?

Melbi is in active alpha development. Try it out, report bugs, and help shape the language.