Invoke an export

For a command-style module, Wago uses _start. For a module that exports ordinary functions, select one with --invoke or -e:

wago run --invoke add math.wasm 20 22

Wago decodes and validates the module, compiles it to native code, creates an instance, calls the export, and prints the result.

Typed arguments

Arguments are decoded from the export's Wasm signature. Plain values usually do what you mean:

wago run --invoke fib fib.wasm 30

Add a suffix when you want the type to be explicit:

wago run --invoke mix numbers.wasm 42 7:i64 3.5:f64

The scalar suffixes are i32, i64, f32, and f64. Wago checks the argument count and every type before entering guest code.

Put runtime flags before the module

Everything after the module path belongs to the exported function. This lets a guest receive an argument such as --verbose without Wago claiming it.

Core feature sets

Wago defaults to the WebAssembly Core 2 compatibility set. Opt into the complete supported Core 3 set when the module needs it:

wago run --core 3 generated.wasm

Unsupported or disabled features fail during decoding or validation. Wago does not quietly skip instructions or malformed structured sections.

Command modules

If the module exports _start, run it without --invoke:

wago run app.wasm hello world

Wago exposes the arguments after the module to the guest. A host exit becomes the process exit code; other traps are reported as runtime failures.

Next

• Inspect imports and validate the module
• Run in watch mode
• Return to Run a module