wasm-overhead-research/docs/WASMER_COMPATIBILITY.md

Wasmer Runtime Compatibility Guide

This document outlines the compatibility of different WASM implementations with the Wasmer runtime and SDKs.

Runtime Compatibility Matrix

Implementation	Runtime Type	Wasmer Compatible	Node.js Compatible	Notes
QuickJS	WASI	✅ Excellent	✅ Yes	Full JS engine, 286KB gzipped
Porffor	Standard WASM	⚠️ Partial	✅ Yes	Requires legacy exceptions support
Javy	WASI (Dynamic)	⚠️ Partial	✅ Yes	Requires plugin loading, 488KB
Go/TinyGo	Go Runtime	❌ No	✅ Yes	Requires wasm_exec.js
Goja	Go Runtime	❌ No	✅ Yes	Requires wasm_exec.js

Wasmer-Ready Implementations

1. QuickJS (Recommended for Full JS Engine)

Size: 286KB gzipped
Runtime: WASI (wasm32-wasip1)
Compatibility: ✅ Perfect Wasmer compatibility

# Test with Wasmer
make test-quickjs-wasmer

# Or manually
wasmer run implementations/quickjs/target/wasm32-wasip1/release/quickjs_transform.wasm

Advantages:

• Full JavaScript engine with ECMAScript compatibility
• One-time 286KB cost + minimal string overhead
• Excellent scaling for multiple operations
• 92% smaller than Goja
• Direct WASI compatibility

2. Porffor (Size Optimized, Limited Wasmer Support)

Size: 75KB gzipped Runtime: Standard WASM with legacy exceptions Compatibility: ⚠️ Requires legacy exceptions support

# Test with Wasmer (requires legacy exceptions)
make test-porffor-wasmer

# Or manually (may need --enable-all flag)
wasmer run implementations/porffor/transform.wasm --enable-all

Advantages:

• Smallest single operation (75KB)
• AOT compiled JavaScript
• Zero runtime overhead

Limitations:

• Uses legacy exceptions not supported by default in Wasmer
• May require special Wasmer configuration
• Better suited for Node.js runtime

3. Javy (Limited Wasmer Support)

Size: 488KB + 4KB per module
Runtime: WASI with dynamic linking
Compatibility: ⚠️ Requires special plugin handling

# Note: Javy dynamic modules need plugin.wasm
# Standard Wasmer doesn't handle dynamic linking automatically

Limitations:

• Dynamic linking not standard in Wasmer
• Requires custom plugin loading logic
• Better suited for Node.js WASI runtime

Wasmer SDK Integration

For JavaScript/TypeScript Projects (Wasmer-JS)

Recommended: QuickJS or Porffor

import { init, WASI } from "@wasmer/wasi";

// Initialize WASI
await init();
const wasi = new WASI({
  env: {},
  args: []
});

// Load QuickJS WASM
const wasmBytes = await fetch("quickjs_transform.wasm").then(r => r.arrayBuffer());
const module = await WebAssembly.compile(wasmBytes);
const instance = await wasi.instantiate(module, {});

// Use the instance
const result = instance.exports.transform_data(inputPtr);

For Other Languages (Wasmer SDKs)

Supported Languages: Python, Rust, C/C++, Go, PHP, Ruby, Java, C#

Recommended: QuickJS (full JS engine) or Porffor (size-optimized)

# Python example with Wasmer
from wasmer import engine, Store, Module, Instance, wasi

# Load WASM module
store = Store(engine.JIT())
module = Module(store, open("quickjs_transform.wasm", "rb").read())

# Create WASI environment
wasi_env = wasi.StateBuilder("quickjs").finalize()
import_object = wasi_env.generate_import_object(store, module)

# Instantiate and run
instance = Instance(module, import_object)
result = instance.exports.transform_data(input_data)

Testing Instructions

Install Wasmer

curl https://get.wasmer.io -sSfL | sh
source ~/.bashrc

Test All WASI-Compatible Implementations

# Test all Wasmer-compatible implementations
make test-wasmer

# Test individual implementations
make test-quickjs-wasmer
make test-porffor-wasmer

Manual Testing

# QuickJS (WASI)
echo '{"test": "data"}' | wasmer run implementations/quickjs/target/wasm32-wasip1/release/quickjs_transform.wasm

# Porffor (Standard WASM)
echo '{"test": "data"}' | wasmer run implementations/porffor/transform.wasm

Recommendations by Use Case

Single JavaScript Operation

Use: Porffor (75KB)

• Smallest size
• Standard WASM
• Perfect Wasmer compatibility

Multiple JavaScript Operations (4+)

Use: QuickJS (286KB + minimal overhead)

• Full JavaScript engine
• Excellent scaling
• WASI compatibility

Microservices Architecture

Use: QuickJS or Porffor

• Both have excellent Wasmer SDK support
• Choose based on size vs. JS compatibility needs

Web Applications (Wasmer-JS)

Use: QuickJS or Porffor

• Both work perfectly with Wasmer-JS
• No special runtime requirements

Migration from Node.js

If you're currently using Node.js-specific implementations:

1. From Go/TinyGo: Migrate to Porffor for size or QuickJS for JS compatibility
2. From Goja: Migrate to QuickJS (92% size reduction, same JS engine model)
3. From Javy: Consider QuickJS for better Wasmer compatibility

Build Commands

# Build Wasmer-compatible implementations
make build-quickjs IMPL=quickjs
make build-porffor IMPL=porffor

# Test with Wasmer
make test-wasmer

Summary

Best for Wasmer SDK Integration:

1. QuickJS: Full JavaScript engine, excellent WASI compatibility (283KB) ⭐ VERIFIED WORKING
2. Porffor: Size-optimized but incompatible with Wasmer (75KB) ❌ NOT SUPPORTED

Verified Test Results:

• ✅ QuickJS + Wasmer: Perfect compatibility, tested and working
• ❌ Porffor + Wasmer: Legacy exceptions not supported, even with --enable-all
• ⚠️ Javy + Wasmer: Dynamic linking requires special handling

Final Recommendation: Use QuickJS as the primary choice for Wasmer SDK integration. It provides perfect WASI compatibility with full JavaScript engine capabilities at 283KB gzipped, making it ideal for production Wasmer deployments across all supported programming languages.