diff --git a/.dockerignore b/.dockerignore
new file mode 100644
index 00000000..11b226d8
--- /dev/null
+++ b/.dockerignore
@@ -0,0 +1,6 @@
+*
+!package.json
+!package-lock.json
+!tsconfig.json
+!bin
+!src
diff --git a/Dockerfile b/Dockerfile
new file mode 100644
index 00000000..62ff3372
--- /dev/null
+++ b/Dockerfile
@@ -0,0 +1,22 @@
+FROM node:14.16.0-buster
+
+ARG UID=1000
+ARG GID=1000
+ARG WASI_SDK_VERSION_MAJOR=12
+ARG WASI_SDK_VERSION_MINOR=0
+
+ENV WASI_ROOT=/home/node/wasi-sdk-12.0
+
+RUN wget https://github.com/WebAssembly/wasi-sdk/releases/download/wasi-sdk-${WASI_SDK_VERSION_MAJOR}/wasi-sdk-${WASI_SDK_VERSION_MAJOR}.${WASI_SDK_VERSION_MINOR}-linux.tar.gz -P /tmp
+
+RUN tar xvf /tmp/wasi-sdk-${WASI_SDK_VERSION_MAJOR}.${WASI_SDK_VERSION_MINOR}-linux.tar.gz --directory /home/node
+
+RUN mkdir /home/node/llhttp
+
+WORKDIR /home/node/llhttp
+
+COPY . .
+
+RUN npm ci
+
+USER node
diff --git a/bin/build_wasm.ts b/bin/build_wasm.ts
new file mode 100644
index 00000000..f80fef77
--- /dev/null
+++ b/bin/build_wasm.ts
@@ -0,0 +1,80 @@
+import { execSync } from 'child_process';
+import { copyFileSync, mkdirSync, writeFileSync } from 'fs';
+import { stringify } from 'javascript-stringify';
+import { join, resolve } from 'path';
+import { constants } from '..';
+
+const { WASI_ROOT } = process.env;
+const WASM_OUT = resolve(__dirname, '../build/wasm');
+const WASM_SRC = resolve(__dirname, '../');
+
+if (process.argv[2] === '--setup') {
+  try {
+    mkdirSync(join(WASM_SRC, 'build'));
+    process.exit(0);
+  } catch (error) {
+    if (error.code !== 'EEXIST') {
+      throw error;
+    }
+    process.exit(0);
+  }
+}
+
+if (process.argv[2] === '--docker') {
+  let cmd = 'docker run --rm -it';
+  // Try to avoid root permission problems on compiled assets
+  // when running on linux.
+  // It will work flawessly if uid === gid === 1000
+  // there will be some warnings otherwise.
+  if (process.platform === 'linux') {
+    cmd += ` --user ${process.getuid()}:${process.getegid()}`;
+  }
+  cmd += ` --mount type=bind,source=${WASM_SRC}/build,target=/home/node/llhttp/build llhttp_wasm_builder npm run wasm`;
+  execSync(cmd, { cwd: WASM_SRC, stdio: 'inherit' });
+  process.exit(0);
+}
+
+if (!WASI_ROOT) {
+  throw new Error('Please setup the WASI_ROOT env variable.');
+}
+
+try {
+  mkdirSync(WASM_OUT);
+} catch (error) {
+  if (error.code !== 'EEXIST') {
+    throw error;
+  }
+}
+
+// Build ts
+execSync('npm run build', { cwd: WASM_SRC, stdio: 'inherit' });
+
+// Build wasm binary
+execSync(`${WASI_ROOT}/bin/clang \
+ --sysroot=${WASI_ROOT}/share/wasi-sysroot \
+ -target wasm32-unknown-wasi \
+ -Ofast \
+ -fno-exceptions \
+ -fvisibility=hidden \
+ -mexec-model=reactor \
+ -Wl,-error-limit=0 \
+ -Wl,-O3 \
+ -Wl,--lto-O3 \
+ -Wl,--strip-all \
+ -Wl,--allow-undefined \
+ -Wl,--export-dynamic \
+ -Wl,--export-table \
+ -Wl,--export=malloc \
+ -Wl,--export=free \
+ ${join(WASM_SRC, 'build', 'c')}/*.c \
+ ${join(WASM_SRC, 'src', 'native')}/*.c \
+ -I${join(WASM_SRC, 'build')} \
+ -o ${join(WASM_OUT, 'llhttp.wasm')}`, { stdio: 'inherit' });
+
+// Copy constants for `.js` and `.ts` users.
+copyFileSync(join(WASM_SRC, 'lib', 'llhttp', 'constants.js'), join(WASM_OUT, 'constants.js'));
+copyFileSync(join(WASM_SRC, 'lib', 'llhttp', 'constants.js.map'), join(WASM_OUT, 'constants.js.map'));
+copyFileSync(join(WASM_SRC, 'lib', 'llhttp', 'constants.d.ts'), join(WASM_OUT, 'constants.d.ts'));
+copyFileSync(join(WASM_SRC, 'lib', 'llhttp', 'utils.js'), join(WASM_OUT, 'utils.js'));
+copyFileSync(join(WASM_SRC, 'lib', 'llhttp', 'utils.js.map'), join(WASM_OUT, 'utils.js.map'));
+copyFileSync(join(WASM_SRC, 'lib', 'llhttp', 'utils.d.ts'), join(WASM_OUT, 'utils.d.ts'));
diff --git a/examples/wasm.ts b/examples/wasm.ts
new file mode 100644
index 00000000..995fed83
--- /dev/null
+++ b/examples/wasm.ts
@@ -0,0 +1,248 @@
+/**
+ * A minimal Parser that mimicks a small fraction of the Node.js parser
+ * API.
+ * To run:
+ * - `npm run build-wasm`
+ * - `npx ts-node examples/wasm.ts`
+ */
+import { readFileSync } from 'fs';
+import { resolve } from 'path';
+import * as constants from '../build/wasm/constants';
+
+const bin = readFileSync(resolve(__dirname, '../build/wasm/llhttp.wasm'));
+const mod = new WebAssembly.Module(bin);
+
+const REQUEST = constants.TYPE.REQUEST;
+const RESPONSE = constants.TYPE.RESPONSE;
+const kOnMessageBegin = 0;
+const kOnHeaders = 1;
+const kOnHeadersComplete = 2;
+const kOnBody = 3;
+const kOnMessageComplete = 4;
+const kOnExecute = 5;
+
+const kPtr = Symbol('kPtr');
+const kUrl = Symbol('kUrl');
+const kStatusMessage = Symbol('kStatusMessage');
+const kHeadersFields = Symbol('kHeadersFields');
+const kHeadersValues = Symbol('kHeadersValues');
+const kBody = Symbol('kBody');
+const kReset = Symbol('kReset');
+const kCheckErr = Symbol('kCheckErr');
+
+const cstr = (ptr: number, len: number): string =>
+  Buffer.from(memory.buffer, ptr, len).toString();
+
+const wasm_on_message_begin = (p: number) => {
+  const i = instMap.get(p);
+  i[kReset]();
+  return i[kOnMessageBegin]();
+};
+
+const wasm_on_url = (p: number, at: number, length: number) => {
+  instMap.get(p)[kUrl] = cstr(at, length);
+  return 0;
+};
+
+const wasm_on_status = (p: number, at: number, length: number) => {
+  instMap.get(p)[kStatusMessage] = cstr(at, length);
+  return 0;
+};
+
+const wasm_on_header_field = (p: number, at: number, length: number) => {
+  const i= instMap.get(p)
+  i[kHeadersFields].push(cstr(at, length));
+  return 0;
+};
+
+const wasm_on_header_value = (p: number, at: number, length: number) => {
+  const i = instMap.get(p);
+  i[kHeadersValues].push(cstr(at, length));
+  return 0;
+};
+
+const wasm_on_headers_complete = (p: number) => {
+  const i = instMap.get(p);
+  const type = get_type(p);
+  const versionMajor = get_version_major(p);
+  const versionMinor = get_version_minor(p);
+  const rawHeaders = [];
+  let method;
+  let url;
+  let statusCode;
+  let statusMessage;
+  const upgrade = get_upgrade(p);
+  const shouldKeepAlive = should_keep_alive(p);
+
+  for (let c = 0; c < i[kHeadersFields].length; c++) {
+    rawHeaders.push(i[kHeadersFields][c], i[kHeadersValues][c])
+  }
+
+  if (type === HTTPParser.REQUEST) {
+    method = constants.METHODS[get_method(p)];
+    url = i[kUrl];
+  } else if (type === HTTPParser.RESPONSE) {
+    statusCode = get_status_code(p);
+    statusMessage = i[kStatusMessage];
+  }
+  return i[kOnHeadersComplete](versionMajor, versionMinor, rawHeaders, method,
+url, statusCode, statusMessage, upgrade, shouldKeepAlive);
+};
+
+const wasm_on_body = (p: number, at: number, length: number) => {
+  const i = instMap.get(p);
+  const body = Buffer.from(memory.buffer, at, length);
+  return i[kOnBody](body);
+};
+
+const wasm_on_message_complete = (p: number) => {
+  return instMap.get(p)[kOnMessageComplete]();
+};
+
+const instMap = new Map();
+
+const inst = new WebAssembly.Instance(mod, {
+  env: {
+    wasm_on_message_begin,
+    wasm_on_url,
+    wasm_on_status,
+    wasm_on_header_field,
+    wasm_on_header_value,
+    wasm_on_headers_complete,
+    wasm_on_body,
+    wasm_on_message_complete,
+  },
+});
+
+const memory = inst.exports.memory as any;
+const alloc = inst.exports.llhttp_alloc as CallableFunction;
+const malloc = inst.exports.malloc as CallableFunction;
+const execute = inst.exports.llhttp_execute as CallableFunction;
+const get_type = inst.exports.llhttp_get_type as CallableFunction;
+const get_upgrade = inst.exports.llhttp_get_upgrade as CallableFunction;
+const should_keep_alive = inst.exports.llhttp_should_keep_alive as CallableFunction;
+const get_method = inst.exports.llhttp_get_method as CallableFunction;
+const get_status_code = inst.exports.llhttp_get_status_code as CallableFunction;
+const get_version_minor = inst.exports.llhttp_get_http_minor as CallableFunction;
+const get_version_major = inst.exports.llhttp_get_http_major as CallableFunction;
+const get_error_reason = inst.exports.llhttp_get_error_reason as CallableFunction;
+const free = inst.exports.free as CallableFunction;
+const initialize = inst.exports._initialize as CallableFunction;
+
+initialize(); // wasi reactor
+
+class HTTPParser {
+  static REQUEST = REQUEST;
+  static RESPONSE = RESPONSE;
+  static kOnMessageBegin = kOnMessageBegin;
+  static kOnHeaders = kOnHeaders;
+  static kOnHeadersComplete = kOnHeadersComplete;
+  static kOnBody = kOnBody;
+  static kOnMessageComplete = kOnMessageComplete;
+  static kOnExecute = kOnExecute;
+
+  [kPtr]: number;
+  [kUrl]: string;
+  [kStatusMessage]: null|string;
+  [kHeadersFields]: []|[string];
+  [kHeadersValues]: []|[string];
+  [kBody]: null|Buffer;
+
+  constructor(type: constants.TYPE) {
+    this[kPtr] = alloc(constants.TYPE[type]);
+    instMap.set(this[kPtr], this);
+
+    this[kUrl] = '';
+    this[kStatusMessage] = null;
+    this[kHeadersFields] = [];
+    this[kHeadersValues] = [];
+    this[kBody] = null;
+  }
+ 
+  [kReset]() {
+    this[kUrl] = '';
+    this[kStatusMessage] = null;
+    this[kHeadersFields] = [];
+    this[kHeadersValues] = [];
+    this[kBody] = null;
+  }
+
+  [kOnMessageBegin]() {
+    return 0;
+  }
+
+  [kOnHeaders](rawHeaders: [string]) {}
+
+  [kOnHeadersComplete](versionMajor: number, versionMinor: number, rawHeaders: [string], method: string,
+    url: string, statusCode: number, statusMessage: string, upgrade: boolean, shouldKeepAlive: boolean) {
+    return 0;
+  }
+
+  [kOnBody](body: Buffer) {
+    this[kBody] = body;
+    return 0;
+  }
+
+  [kOnMessageComplete]() {
+    return 0;
+  }
+
+  destroy() {
+    instMap.delete(this[kPtr]);
+    free(this[kPtr]);
+  }
+
+  execute(data: Buffer) {
+    const ptr = malloc(data.byteLength);
+    const u8 = new Uint8Array(memory.buffer);
+    u8.set(data, ptr);
+    const ret = execute(this[kPtr], ptr, data.length);
+    free(ptr);
+    this[kCheckErr](ret);
+    return ret;
+  }
+
+  [kCheckErr](n: number) {
+    if (n === constants.ERROR.OK) {
+      return;
+    }
+    const ptr = get_error_reason(this[kPtr]);
+    const u8 = new Uint8Array(memory.buffer);
+    const len = u8.indexOf(0, ptr) - ptr;
+    throw new Error(cstr(ptr, len));
+  }
+}
+
+
+{
+  const p = new HTTPParser(HTTPParser.REQUEST);
+
+  p.execute(Buffer.from([
+    'POST /owo HTTP/1.1',
+    'X: Y',
+    'Content-Length: 9',
+    '',
+    'uh, meow?',
+    '',
+  ].join('\r\n')));
+
+  console.log(p);
+
+  p.destroy();
+}
+
+{
+  const p = new HTTPParser(HTTPParser.RESPONSE);
+
+  p.execute(Buffer.from([
+    'HTTP/1.1 200 OK',
+    'X: Y',
+    'Content-Length: 9',
+    '',
+    'uh, meow?'
+  ].join('\r\n')));
+
+  console.log(p);
+
+  p.destroy();
+}
diff --git a/package-lock.json b/package-lock.json
index 312f761f..6a48a868 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -610,6 +610,12 @@
       "integrity": "sha1-6PvzdNxVb/iUehDcsFctYz8s+hA=",
       "dev": true
     },
+    "javascript-stringify": {
+      "version": "2.0.1",
+      "resolved": "https://registry.npmjs.org/javascript-stringify/-/javascript-stringify-2.0.1.tgz",
+      "integrity": "sha512-yV+gqbd5vaOYjqlbk16EG89xB5udgjqQF3C5FAORDg4f/IS1Yc5ERCv5e/57yBcfJYw05V5JyIXabhwb75Xxow==",
+      "dev": true
+    },
     "js-tokens": {
       "version": "4.0.0",
       "resolved": "https://registry.npmjs.org/js-tokens/-/js-tokens-4.0.0.tgz",
diff --git a/package.json b/package.json
index bde42077..c897e732 100644
--- a/package.json
+++ b/package.json
@@ -12,6 +12,9 @@
     "bench": "ts-node bench/",
     "build": "ts-node bin/generate.ts",
     "build-ts": "tsc",
+    "prebuild-wasm": "docker build -t llhttp_wasm_builder . && npm run wasm -- --setup",
+    "build-wasm": "npm run wasm -- --docker",
+    "wasm": "ts-node bin/build_wasm.ts",
     "clean": "rm -rf lib && rm -rf test/tmp",
     "prepare": "npm run clean && npm run build-ts",
     "lint": "tslint -c tslint.json bin/*.ts src/*.ts src/**/*.ts test/*.ts test/**/*.ts",
@@ -38,6 +41,7 @@
   "devDependencies": {
     "@types/mocha": "^5.2.7",
     "@types/node": "^10.17.52",
+    "javascript-stringify": "^2.0.1",
     "llparse-dot": "^1.0.1",
     "llparse-test-fixture": "^5.0.1",
     "mdgator": "^1.1.2",
diff --git a/src/native/api.c b/src/native/api.c
index 1d68639f..8a4bdd26 100644
--- a/src/native/api.c
+++ b/src/native/api.c
@@ -24,6 +24,70 @@ void llhttp_init(llhttp_t* parser, llhttp_type_t type,
 }
 
 
+#if defined(__wasm__)
+
+extern int wasm_on_message_begin(llhttp_t * p);
+extern int wasm_on_url(llhttp_t* p, const char* at, size_t length);
+extern int wasm_on_status(llhttp_t* p, const char* at, size_t length);
+extern int wasm_on_header_field(llhttp_t* p, const char* at, size_t length);
+extern int wasm_on_header_value(llhttp_t* p, const char* at, size_t length);
+extern int wasm_on_headers_complete(llhttp_t * p);
+extern int wasm_on_body(llhttp_t* p, const char* at, size_t length);
+extern int wasm_on_message_complete(llhttp_t * p);
+
+const llhttp_settings_t wasm_settings = {
+  wasm_on_message_begin,
+  wasm_on_url,
+  wasm_on_status,
+  wasm_on_header_field,
+  wasm_on_header_value,
+  wasm_on_headers_complete,
+  wasm_on_body,
+  wasm_on_message_complete,
+  NULL,
+  NULL,
+};
+
+
+llhttp_t* llhttp_alloc(llhttp_type_t type) {
+  llhttp_t* parser = malloc(sizeof(llhttp_t));
+  llhttp_init(parser, type, &wasm_settings);
+  return parser;
+}
+
+void llhttp_free(llhttp_t* parser) {
+  free(parser);
+}
+
+/* Some getters required to get stuff from the parser */
+
+uint8_t llhttp_get_type(llhttp_t* parser) {
+  return parser->type;
+}
+
+uint8_t llhttp_get_http_major(llhttp_t* parser) {
+  return parser->http_major;
+}
+
+uint8_t llhttp_get_http_minor(llhttp_t* parser) {
+  return parser->http_minor;
+}
+
+uint8_t llhttp_get_method(llhttp_t* parser) {
+  return parser->method;
+}
+
+int llhttp_get_status_code(llhttp_t* parser) {
+  return parser->status_code;
+}
+
+uint8_t llhttp_get_upgrade(llhttp_t* parser) {
+  return parser->upgrade;
+}
+
+#endif  // defined(__wasm__)
+
+
 void llhttp_reset(llhttp_t* parser) {
   llhttp_type_t type = parser->type;
   const llhttp_settings_t* settings = parser->settings;
diff --git a/src/native/api.h b/src/native/api.h
index fb19618d..7fdbfc10 100644
--- a/src/native/api.h
+++ b/src/native/api.h
@@ -5,6 +5,12 @@ extern "C" {
 #endif
 #include <stddef.h>
 
+#if defined(__wasm__)
+#define LLHTTP_EXPORT __attribute__((visibility("default")))
+#else
+#define LLHTTP_EXPORT
+#endif
+
 typedef llhttp__internal_t llhttp_t;
 typedef struct llhttp_settings_s llhttp_settings_t;
 
@@ -55,15 +61,46 @@ struct llhttp_settings_s {
  * the `parser` here. In practice, `settings` has to be either a static
  * variable or be allocated with `malloc`, `new`, etc.
  */
+LLHTTP_EXPORT
 void llhttp_init(llhttp_t* parser, llhttp_type_t type,
                  const llhttp_settings_t* settings);
 
+#if defined(__wasm__)
+
+LLHTTP_EXPORT
+llhttp_t* llhttp_alloc(llhttp_type_t type);
+
+LLHTTP_EXPORT
+void llhttp_free(llhttp_t* parser);
+
+LLHTTP_EXPORT
+uint8_t llhttp_get_type(llhttp_t* parser);
+
+LLHTTP_EXPORT
+uint8_t llhttp_get_http_major(llhttp_t* parser);
+
+LLHTTP_EXPORT
+uint8_t llhttp_get_http_minor(llhttp_t* parser);
+
+LLHTTP_EXPORT
+uint8_t llhttp_get_method(llhttp_t* parser);
+
+LLHTTP_EXPORT
+int llhttp_get_status_code(llhttp_t* parser);
+
+LLHTTP_EXPORT
+uint8_t llhttp_get_upgrade(llhttp_t* parser);
+
+#endif  // defined(__wasm__)
+
 /* Reset an already initialized parser back to the start state, preserving the
  * existing parser type, callback settings, user data, and lenient flags.
  */
+LLHTTP_EXPORT
 void llhttp_reset(llhttp_t* parser);
 
 /* Initialize the settings object */
+LLHTTP_EXPORT
 void llhttp_settings_init(llhttp_settings_t* settings);
 
 /* Parse full or partial request/response, invoking user callbacks along the
@@ -82,6 +119,7 @@ void llhttp_settings_init(llhttp_settings_t* settings);
  * to return the same error upon each successive call up until `llhttp_init()`
  * is called.
  */
+LLHTTP_EXPORT
 llhttp_errno_t llhttp_execute(llhttp_t* parser, const char* data, size_t len);
 
 /* This method should be called when the other side has no further bytes to
@@ -92,16 +130,19 @@ llhttp_errno_t llhttp_execute(llhttp_t* parser, const char* data, size_t len);
  * connection. This method will invoke `on_message_complete()` callback if the
  * request was terminated safely. Otherwise a error code would be returned.
  */
+LLHTTP_EXPORT
 llhttp_errno_t llhttp_finish(llhttp_t* parser);
 
 /* Returns `1` if the incoming message is parsed until the last byte, and has
  * to be completed by calling `llhttp_finish()` on EOF
  */
+LLHTTP_EXPORT
 int llhttp_message_needs_eof(const llhttp_t* parser);
 
 /* Returns `1` if there might be any other messages following the last that was
  * successfully parsed.
  */
+LLHTTP_EXPORT
 int llhttp_should_keep_alive(const llhttp_t* parser);
 
 /* Make further calls of `llhttp_execute()` return `HPE_PAUSED` and set
@@ -110,6 +151,7 @@ int llhttp_should_keep_alive(const llhttp_t* parser);
  * Important: do not call this from user callbacks! User callbacks must return
  * `HPE_PAUSED` if pausing is required.
  */
+LLHTTP_EXPORT
 void llhttp_pause(llhttp_t* parser);
 
 /* Might be called to resume the execution after the pause in user's callback.
@@ -117,6 +159,7 @@ void llhttp_pause(llhttp_t* parser);
  *
  * Call this only if `llhttp_execute()` returns `HPE_PAUSED`.
  */
+LLHTTP_EXPORT
 void llhttp_resume(llhttp_t* parser);
 
 /* Might be called to resume the execution after the pause in user's callback.
@@ -124,9 +167,11 @@ void llhttp_resume(llhttp_t* parser);
  *
  * Call this only if `llhttp_execute()` returns `HPE_PAUSED_UPGRADE`
  */
+LLHTTP_EXPORT
 void llhttp_resume_after_upgrade(llhttp_t* parser);
 
 /* Returns the latest return error */
+LLHTTP_EXPORT
 llhttp_errno_t llhttp_get_errno(const llhttp_t* parser);
 
 /* Returns the verbal explanation of the latest returned error.
@@ -134,6 +179,7 @@ llhttp_errno_t llhttp_get_errno(const llhttp_t* parser);
  * Note: User callback should set error reason when returning the error. See
  * `llhttp_set_error_reason()` for details.
  */
+LLHTTP_EXPORT
 const char* llhttp_get_error_reason(const llhttp_t* parser);
 
 /* Assign verbal description to the returned error. Must be called in user
@@ -141,6 +187,7 @@ const char* llhttp_get_error_reason(const llhttp_t* parser);
  *
  * Note: `HPE_USER` error code might be useful in user callbacks.
  */
+LLHTTP_EXPORT
 void llhttp_set_error_reason(llhttp_t* parser, const char* reason);
 
 /* Returns the pointer to the last parsed byte before the returned error. The
@@ -148,12 +195,15 @@ void llhttp_set_error_reason(llhttp_t* parser, const char* reason);
  *
  * Note: this method might be useful for counting the number of parsed bytes.
  */
+LLHTTP_EXPORT
 const char* llhttp_get_error_pos(const llhttp_t* parser);
 
 /* Returns textual name of error code */
+LLHTTP_EXPORT
 const char* llhttp_errno_name(llhttp_errno_t err);
 
 /* Returns textual name of HTTP method */
+LLHTTP_EXPORT
 const char* llhttp_method_name(llhttp_method_t method);
 
 
@@ -166,6 +216,7 @@ const char* llhttp_method_name(llhttp_method_t method);
  *
  * **(USE AT YOUR OWN RISK)**
  */
+LLHTTP_EXPORT
 void llhttp_set_lenient_headers(llhttp_t* parser, int enabled);
 
 
@@ -179,6 +230,7 @@ void llhttp_set_lenient_headers(llhttp_t* parser, int enabled);
  *
  * **(USE AT YOUR OWN RISK)**
  */
+LLHTTP_EXPORT
 void llhttp_set_lenient_chunked_length(llhttp_t* parser, int enabled);