diff --git a/Cargo.lock b/Cargo.lock
index 8b084c27b57..77e24687daa 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -562,18 +562,13 @@ dependencies = [
 ]
 
 [[package]]
-name = "parcel-js-swc"
+name = "parcel-js-swc-core"
 version = "0.1.0"
 dependencies = [
  "Inflector",
  "data-encoding",
  "dunce",
  "indoc",
- "jemallocator",
- "mimalloc",
- "napi",
- "napi-build",
- "napi-derive",
  "serde",
  "serde_bytes",
  "sha-1",
@@ -583,6 +578,28 @@ dependencies = [
  "swc_ecmascript",
 ]
 
+[[package]]
+name = "parcel-js-swc-napi"
+version = "0.1.0"
+dependencies = [
+ "jemallocator",
+ "mimalloc",
+ "napi",
+ "napi-build",
+ "napi-derive",
+ "parcel-js-swc-core",
+]
+
+[[package]]
+name = "parcel-js-swc-wasm"
+version = "0.1.0"
+dependencies = [
+ "js-sys",
+ "parcel-js-swc-core",
+ "serde-wasm-bindgen",
+ "wasm-bindgen",
+]
+
 [[package]]
 name = "percent-encoding"
 version = "2.1.0"
@@ -847,6 +864,18 @@ dependencies = [
  "serde_derive",
 ]
 
+[[package]]
+name = "serde-wasm-bindgen"
+version = "0.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1515286919c7a28f96c362f42cd42aec7ef6d417334118be69d1ad96160aa5f5"
+dependencies = [
+ "fnv",
+ "js-sys",
+ "serde",
+ "wasm-bindgen",
+]
+
 [[package]]
 name = "serde_bytes"
 version = "0.11.5"
diff --git a/Cargo.toml b/Cargo.toml
index c5e3cedef5d..440beec791c 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -1,6 +1,7 @@
 [workspace]
-members = ["packages/transformers/js", "packages/utils/fs-search"]
-
-[profile.release]
-opt-level = 3
-# lto = true
+members = [
+  "packages/transformers/js/core",
+  "packages/transformers/js/napi",
+  "packages/transformers/js/wasm",
+  "packages/utils/fs-search",
+]
diff --git a/packages/transformers/js/Cargo.toml b/packages/transformers/js/core/Cargo.toml
similarity index 57%
rename from packages/transformers/js/Cargo.toml
rename to packages/transformers/js/core/Cargo.toml
index 0f2b82705ad..55068ed732d 100644
--- a/packages/transformers/js/Cargo.toml
+++ b/packages/transformers/js/core/Cargo.toml
@@ -1,14 +1,13 @@
 [package]
 authors = ["Devon Govett <devongovett@gmail.com>"]
-name = "parcel-js-swc"
+name = "parcel-js-swc-core"
 version = "0.1.0"
+edition = "2018"
 
 [lib]
-crate-type = ["cdylib"]
+crate-type = ["rlib"]
 
 [dependencies]
-napi = { version = "1", features = ["serde-json"] }
-napi-derive = "1"
 swc_ecmascript = { version = "0.36.0", features = ["parser", "transforms", "module", "optimization", "react", "typescript", "utils", "visit", "codegen", "utils"] }
 swc_ecma_preset_env = "0.20.1"
 swc_common = { version = "0.10.19", features = ["tty-emitter", "sourcemap"] }
@@ -20,12 +19,3 @@ Inflector = "0.11.4"
 data-encoding = "2.3.2"
 sha-1 = "0.9.4"
 dunce = "1.0.1"
-
-[target.'cfg(target_os = "macos")'.dependencies]
-jemallocator = { version = "0.3.2", features = ["disable_initial_exec_tls"] }
-
-[target.'cfg(windows)'.dependencies]
-mimalloc = { version = "0.1.25", default-features = false }
-
-[build-dependencies]
-napi-build = { version = "1" }
diff --git a/packages/transformers/js/src/decl_collector.rs b/packages/transformers/js/core/src/decl_collector.rs
similarity index 100%
rename from packages/transformers/js/src/decl_collector.rs
rename to packages/transformers/js/core/src/decl_collector.rs
diff --git a/packages/transformers/js/src/dependency_collector.rs b/packages/transformers/js/core/src/dependency_collector.rs
similarity index 99%
rename from packages/transformers/js/src/dependency_collector.rs
rename to packages/transformers/js/core/src/dependency_collector.rs
index efbba67e457..08e4fa140dc 100644
--- a/packages/transformers/js/src/dependency_collector.rs
+++ b/packages/transformers/js/core/src/dependency_collector.rs
@@ -7,7 +7,7 @@ use swc_common::{SourceMap, SyntaxContext, DUMMY_SP};
 use swc_ecmascript::ast;
 use swc_ecmascript::visit::{Fold, FoldWith};
 
-use utils::*;
+use crate::utils::*;
 
 #[derive(Clone, Debug, Eq, PartialEq, Serialize, Deserialize)]
 pub enum DependencyKind {
diff --git a/packages/transformers/js/src/env_replacer.rs b/packages/transformers/js/core/src/env_replacer.rs
similarity index 99%
rename from packages/transformers/js/src/env_replacer.rs
rename to packages/transformers/js/core/src/env_replacer.rs
index 3c9e6134cf3..fca81b2bcf3 100644
--- a/packages/transformers/js/src/env_replacer.rs
+++ b/packages/transformers/js/core/src/env_replacer.rs
@@ -5,7 +5,7 @@ use swc_common::{SyntaxContext, DUMMY_SP};
 use swc_ecmascript::ast;
 use swc_ecmascript::visit::Fold;
 
-use utils::*;
+use crate::utils::*;
 
 pub struct EnvReplacer<'a> {
   pub replace_env: bool,
diff --git a/packages/transformers/js/src/fs.rs b/packages/transformers/js/core/src/fs.rs
similarity index 99%
rename from packages/transformers/js/src/fs.rs
rename to packages/transformers/js/core/src/fs.rs
index e3a7e5f859c..58bb34acf19 100644
--- a/packages/transformers/js/src/fs.rs
+++ b/packages/transformers/js/core/src/fs.rs
@@ -1,7 +1,7 @@
+use crate::dependency_collector::{DependencyDescriptor, DependencyKind};
 use crate::hoist::{Collect, Import};
 use crate::utils::SourceLocation;
 use data_encoding::{BASE64, HEXLOWER};
-use dependency_collector::{DependencyDescriptor, DependencyKind};
 use std::collections::HashSet;
 use std::path::{Path, PathBuf};
 use swc_atoms::JsWord;
diff --git a/packages/transformers/js/src/global_replacer.rs b/packages/transformers/js/core/src/global_replacer.rs
similarity index 97%
rename from packages/transformers/js/src/global_replacer.rs
rename to packages/transformers/js/core/src/global_replacer.rs
index 2224088a98d..7b4a5326175 100644
--- a/packages/transformers/js/src/global_replacer.rs
+++ b/packages/transformers/js/core/src/global_replacer.rs
@@ -6,8 +6,8 @@ use swc_common::{SourceMap, SyntaxContext, DUMMY_SP};
 use swc_ecmascript::ast;
 use swc_ecmascript::visit::{Fold, FoldWith};
 
-use dependency_collector::{DependencyDescriptor, DependencyKind};
-use utils::{create_require, SourceLocation};
+use crate::dependency_collector::{DependencyDescriptor, DependencyKind};
+use crate::utils::{create_require, SourceLocation};
 
 pub struct GlobalReplacer<'a> {
   pub source_map: &'a SourceMap,
diff --git a/packages/transformers/js/src/hoist.rs b/packages/transformers/js/core/src/hoist.rs
similarity index 100%
rename from packages/transformers/js/src/hoist.rs
rename to packages/transformers/js/core/src/hoist.rs
diff --git a/packages/transformers/js/src/lib.rs b/packages/transformers/js/core/src/lib.rs
similarity index 93%
rename from packages/transformers/js/src/lib.rs
rename to packages/transformers/js/core/src/lib.rs
index d958a8da77f..f7046d38d76 100644
--- a/packages/transformers/js/src/lib.rs
+++ b/packages/transformers/js/core/src/lib.rs
@@ -1,6 +1,3 @@
-extern crate napi;
-#[macro_use]
-extern crate napi_derive;
 extern crate swc_common;
 extern crate swc_ecma_preset_env;
 extern crate swc_ecmascript;
@@ -13,14 +10,6 @@ extern crate serde;
 extern crate serde_bytes;
 extern crate sha1;
 
-#[cfg(target_os = "macos")]
-#[global_allocator]
-static GLOBAL: jemallocator::Jemalloc = jemallocator::Jemalloc;
-
-#[cfg(windows)]
-#[global_allocator]
-static ALLOC: mimalloc::MiMalloc = mimalloc::MiMalloc;
-
 mod decl_collector;
 mod dependency_collector;
 mod env_replacer;
@@ -30,7 +19,6 @@ mod hoist;
 mod modules;
 mod utils;
 
-use napi::{CallContext, JsObject, JsUnknown, Result};
 use std::collections::{HashMap, HashSet};
 use std::str::FromStr;
 
@@ -39,7 +27,6 @@ use swc_common::comments::SingleThreadedComments;
 use swc_common::errors::{DiagnosticBuilder, Emitter, Handler};
 use swc_common::{chain, sync::Lrc, FileName, Globals, Mark, SourceMap};
 use swc_ecma_preset_env::{preset_env, Mode::Entry, Targets, Version, Versions};
-use swc_ecmascript::ast;
 use swc_ecmascript::ast::Module;
 use swc_ecmascript::codegen::text_writer::JsWriter;
 use swc_ecmascript::parser::lexer::Lexer;
@@ -62,7 +49,7 @@ use modules::esm2cjs;
 use utils::{CodeHighlight, Diagnostic, SourceLocation};
 
 #[derive(Serialize, Debug, Deserialize)]
-struct Config {
+pub struct Config {
   filename: String,
   #[serde(with = "serde_bytes")]
   code: Vec<u8>,
@@ -85,9 +72,9 @@ struct Config {
 }
 
 #[derive(Serialize, Debug, Deserialize, Default)]
-struct TransformResult<'a> {
+pub struct TransformResult {
   #[serde(with = "serde_bytes")]
-  code: &'a [u8],
+  code: Vec<u8>,
   map: Option<String>,
   shebang: Option<String>,
   dependencies: Vec<DependencyDescriptor>,
@@ -136,12 +123,8 @@ impl Emitter for ErrorBuffer {
   }
 }
 
-#[js_function(1)]
-fn transform(ctx: CallContext) -> Result<JsUnknown> {
-  let opts = ctx.get::<JsObject>(0)?;
-  let config: Config = ctx.env.from_js_value(opts)?;
+pub fn transform(config: Config) -> Result<TransformResult, std::io::Error> {
   let mut result = TransformResult::default();
-  let mut code_buf = vec![];
   let mut map_buf = vec![];
 
   let code = unsafe { std::str::from_utf8_unchecked(&config.code) };
@@ -197,7 +180,7 @@ fn transform(ctx: CallContext) -> Result<JsUnknown> {
         .collect();
 
       result.diagnostics = Some(diagnostics);
-      ctx.env.to_js_value(&result)
+      Ok(result)
     }
     Ok((module, comments)) => {
       let mut module = module;
@@ -333,7 +316,7 @@ fn transform(ctx: CallContext) -> Result<JsUnknown> {
                 }
                 Err(diagnostics) => {
                   result.diagnostics = Some(diagnostics);
-                  return ctx.env.to_js_value(&result);
+                  return Ok(result);
                 }
               }
             } else {
@@ -360,9 +343,8 @@ fn transform(ctx: CallContext) -> Result<JsUnknown> {
                 result.map = Some(String::from_utf8(map_buf).unwrap());
               }
             }
-            code_buf = buf;
-            result.code = &code_buf;
-            ctx.env.to_js_value(&result)
+            result.code = buf;
+            Ok(result)
           },
         )
       })
@@ -413,7 +395,7 @@ fn emit(
   comments: SingleThreadedComments,
   program: &Module,
   source_maps: bool,
-) -> Result<(Vec<u8>, Vec<(swc_common::BytePos, swc_common::LineCol)>)> {
+) -> Result<(Vec<u8>, Vec<(swc_common::BytePos, swc_common::LineCol)>), std::io::Error> {
   let mut src_map_buf = vec![];
   let mut buf = vec![];
   {
@@ -440,10 +422,3 @@ fn emit(
 
   return Ok((buf, src_map_buf));
 }
-
-#[module_exports]
-fn init(mut exports: JsObject) -> Result<()> {
-  exports.create_named_method("transform", transform)?;
-
-  Ok(())
-}
diff --git a/packages/transformers/js/src/modules.rs b/packages/transformers/js/core/src/modules.rs
similarity index 100%
rename from packages/transformers/js/src/modules.rs
rename to packages/transformers/js/core/src/modules.rs
diff --git a/packages/transformers/js/src/utils.rs b/packages/transformers/js/core/src/utils.rs
similarity index 100%
rename from packages/transformers/js/src/utils.rs
rename to packages/transformers/js/core/src/utils.rs
diff --git a/packages/transformers/js/napi/Cargo.toml b/packages/transformers/js/napi/Cargo.toml
new file mode 100644
index 00000000000..a70e7b7469b
--- /dev/null
+++ b/packages/transformers/js/napi/Cargo.toml
@@ -0,0 +1,22 @@
+[package]
+authors = ["Devon Govett <devongovett@gmail.com>"]
+name = "parcel-js-swc-napi"
+version = "0.1.0"
+edition = "2018"
+
+[lib]
+crate-type = ["cdylib"]
+
+[dependencies]
+napi = { version = "1", features = ["serde-json"] }
+napi-derive = "1"
+parcel-js-swc-core = { path = "../core" }
+
+[target.'cfg(target_os = "macos")'.dependencies]
+jemallocator = { version = "0.3.2", features = ["disable_initial_exec_tls"] }
+
+[target.'cfg(windows)'.dependencies]
+mimalloc = { version = "0.1.25", default-features = false }
+
+[build-dependencies]
+napi-build = { version = "1" }
diff --git a/packages/transformers/js/build.rs b/packages/transformers/js/napi/build.rs
similarity index 100%
rename from packages/transformers/js/build.rs
rename to packages/transformers/js/napi/build.rs
diff --git a/packages/transformers/js/napi/src/lib.rs b/packages/transformers/js/napi/src/lib.rs
new file mode 100644
index 00000000000..3bdd1206d27
--- /dev/null
+++ b/packages/transformers/js/napi/src/lib.rs
@@ -0,0 +1,30 @@
+extern crate napi;
+#[macro_use]
+extern crate napi_derive;
+extern crate parcel_js_swc_core;
+
+use napi::{CallContext, JsObject, JsUnknown, Result};
+
+#[cfg(target_os = "macos")]
+#[global_allocator]
+static GLOBAL: jemallocator::Jemalloc = jemallocator::Jemalloc;
+
+#[cfg(windows)]
+#[global_allocator]
+static ALLOC: mimalloc::MiMalloc = mimalloc::MiMalloc;
+
+#[js_function(1)]
+fn transform(ctx: CallContext) -> Result<JsUnknown> {
+  let opts = ctx.get::<JsObject>(0)?;
+  let config: parcel_js_swc_core::Config = ctx.env.from_js_value(opts)?;
+
+  let result = parcel_js_swc_core::transform(config)?;
+  ctx.env.to_js_value(&result)
+}
+
+#[module_exports]
+fn init(mut exports: JsObject) -> Result<()> {
+  exports.create_named_method("transform", transform)?;
+
+  Ok(())
+}
diff --git a/packages/transformers/js/native-browser.js b/packages/transformers/js/native-browser.js
new file mode 100644
index 00000000000..e7283914440
--- /dev/null
+++ b/packages/transformers/js/native-browser.js
@@ -0,0 +1,37 @@
+import initFn, {transform} from './wasm/dist-web/parcel_js_swc_wasm.js';
+
+export const init = initFn();
+
+function transformWrapper(config) {
+  let result = transform(config);
+  return {
+    ...result,
+    // Hydrate Uint8Array into Buffer
+    code: Buffer.from(result.code.buffer),
+    // https://github.com/cloudflare/serde-wasm-bindgen/issues/10
+    dependencies: result.dependencies?.map(d => ({
+      ...d,
+      attributes:
+        d.attributes != null
+          ? Object.fromEntries([...d.attributes])
+          : undefined,
+    })),
+    hoist_result:
+      result.hoist_result != null
+        ? {
+            ...result.hoist_result,
+            imported_symbols: Object.fromEntries([
+              ...result.hoist_result.imported_symbols,
+            ]),
+            exported_symbols: Object.fromEntries([
+              ...result.hoist_result.exported_symbols,
+            ]),
+            dynamic_imports: Object.fromEntries([
+              ...result.hoist_result.dynamic_imports,
+            ]),
+          }
+        : undefined,
+  };
+}
+
+export {transformWrapper as transform};
diff --git a/packages/transformers/js/native.js b/packages/transformers/js/native.js
new file mode 100644
index 00000000000..2078585ca48
--- /dev/null
+++ b/packages/transformers/js/native.js
@@ -0,0 +1,56 @@
+let parts = [process.platform, process.arch];
+if (process.platform === 'linux') {
+  const {MUSL, family} = require('detect-libc');
+  if (family === MUSL) {
+    parts.push('musl');
+  } else if (process.arch === 'arm') {
+    parts.push('gnueabihf');
+  } else {
+    parts.push('gnu');
+  }
+} else if (process.platform === 'win32') {
+  parts.push('msvc');
+}
+
+let name = `parcel-swc.${parts.join('-')}.node`;
+if (process.env.PARCEL_BUILD_ENV === 'production') {
+  module.exports = require(`./${name}`);
+} else if (process.env.PARCEL_SWC_WASM) {
+  const {transform} = require('./wasm/dist-node/parcel_js_swc_wasm.js');
+
+  module.exports.transform = function(config) {
+    let result = transform(config);
+    return {
+      ...result,
+      // Hydrate Uint8Array into Buffer
+      code: Buffer.from(result.code.buffer),
+      // https://github.com/cloudflare/serde-wasm-bindgen/issues/10
+      dependencies: result.dependencies?.map(d => ({
+        ...d,
+        attributes:
+          d.attributes != null
+            ? Object.fromEntries([...d.attributes])
+            : undefined,
+      })),
+      hoist_result:
+        result.hoist_result != null
+          ? {
+              ...result.hoist_result,
+              imported_symbols: Object.fromEntries([
+                ...result.hoist_result.imported_symbols,
+              ]),
+              exported_symbols: Object.fromEntries([
+                ...result.hoist_result.exported_symbols,
+              ]),
+              dynamic_imports: Object.fromEntries([
+                ...result.hoist_result.dynamic_imports,
+              ]),
+            }
+          : undefined,
+    };
+  };
+} else if (require('fs').existsSync(require('path').join(__dirname, name))) {
+  module.exports = require(`./${name}`);
+} else {
+  module.exports = require(`self-published/${name}`);
+}
diff --git a/packages/transformers/js/package.json b/packages/transformers/js/package.json
index 5c56cdc8a6b..819f028b9b7 100644
--- a/packages/transformers/js/package.json
+++ b/packages/transformers/js/package.json
@@ -46,7 +46,13 @@
     "tiny-benchy": "^1.0.1"
   },
   "scripts": {
-    "build": "napi build --platform",
-    "build-release": "napi build --platform --release"
+    "build": "napi build --platform --cargo-cwd napi",
+    "build-release": "napi build --platform --release --cargo-cwd napi",
+    "build:wasm-base": "wasm-pack build wasm --no-typescript --release",
+    "build:wasm-node": "yarn build:wasm-base --target nodejs --out-dir dist-node",
+    "build:wasm-web": "CARGO_PROFILE_RELEASE_LTO=true CARGO_PROFILE_RELEASE_PANIC=abort CARGO_PROFILE_RELEASE_OPT_LEVEL=z yarn build:wasm-base --target web --out-dir dist-web"
+  },
+  "browser": {
+    "./native.js": "./native-browser.js"
   }
 }
diff --git a/packages/transformers/js/src/JSTransformer.js b/packages/transformers/js/src/JSTransformer.js
index 3e6fa25e78f..4d531487116 100644
--- a/packages/transformers/js/src/JSTransformer.js
+++ b/packages/transformers/js/src/JSTransformer.js
@@ -3,7 +3,7 @@ import type {JSONObject, EnvMap} from '@parcel/types';
 import type {SchemaEntity} from '@parcel/utils';
 import SourceMap from '@parcel/source-map';
 import {Transformer} from '@parcel/plugin';
-import {transform} from './native';
+import {init, transform} from '../native';
 import {isURL} from '@parcel/utils';
 import path from 'path';
 import browserslist from 'browserslist';
@@ -159,8 +159,11 @@ export default (new Transformer({
       asset.isSplittable = true;
     }
 
-    let code = await asset.getBuffer();
-    let originalMap = await asset.getMap();
+    let [code, originalMap] = await Promise.all([
+      asset.getBuffer(),
+      asset.getMap(),
+      init,
+    ]);
 
     let targets;
     if (asset.isSource) {
diff --git a/packages/transformers/js/src/native.js b/packages/transformers/js/src/native.js
deleted file mode 100644
index aec5859ffde..00000000000
--- a/packages/transformers/js/src/native.js
+++ /dev/null
@@ -1,24 +0,0 @@
-let parts = [process.platform, process.arch];
-if (process.platform === 'linux') {
-  const {MUSL, family} = require('detect-libc');
-  if (family === MUSL) {
-    parts.push('musl');
-  } else if (process.arch === 'arm') {
-    parts.push('gnueabihf');
-  } else {
-    parts.push('gnu');
-  }
-} else if (process.platform === 'win32') {
-  parts.push('msvc');
-}
-
-let name = `parcel-swc.${parts.join('-')}.node`;
-if (process.env.PARCEL_BUILD_ENV === 'production') {
-  module.exports = require(`../${name}`);
-} else if (
-  require('fs').existsSync(require('path').join(__dirname, '..', name))
-) {
-  module.exports = require(`../${name}`);
-} else {
-  module.exports = require(`self-published/${name}`);
-}
diff --git a/packages/transformers/js/wasm/Cargo.toml b/packages/transformers/js/wasm/Cargo.toml
new file mode 100644
index 00000000000..24d2e79095e
--- /dev/null
+++ b/packages/transformers/js/wasm/Cargo.toml
@@ -0,0 +1,14 @@
+[package]
+authors = ["Devon Govett <devongovett@gmail.com>"]
+name = "parcel-js-swc-wasm"
+version = "0.1.0"
+edition = "2018"
+
+[lib]
+crate-type = ["cdylib"]
+
+[dependencies]
+js-sys = "0.3"
+parcel-js-swc-core = { path = "../core" }
+serde-wasm-bindgen = "0.2.0"
+wasm-bindgen = "0.2"
diff --git a/packages/transformers/js/wasm/src/lib.rs b/packages/transformers/js/wasm/src/lib.rs
new file mode 100644
index 00000000000..44f13e3853e
--- /dev/null
+++ b/packages/transformers/js/wasm/src/lib.rs
@@ -0,0 +1,14 @@
+extern crate parcel_js_swc_core;
+
+use js_sys::Error;
+use serde_wasm_bindgen;
+use wasm_bindgen::prelude::*;
+
+#[wasm_bindgen]
+pub fn transform(config_val: JsValue) -> Result<JsValue, JsValue> {
+  let config: parcel_js_swc_core::Config =
+    serde_wasm_bindgen::from_value(config_val).map_err(|err| JsValue::from(err))?;
+  let result = parcel_js_swc_core::transform(config)
+    .map_err(|e| Error::from(JsValue::from_str(&e.to_string())))?;
+  Ok(serde_wasm_bindgen::to_value(&result).map_err(|err| JsValue::from(err))?)
+}