diff --git a/.gitignore b/.gitignore
index 360390b1..7bffbb8c 100644
--- a/.gitignore
+++ b/.gitignore
@@ -15,3 +15,4 @@ test/fixtures/grammars/*
 *.obj
 *.exp
 *.lib
+*.wasm
diff --git a/cli/src/generate/mod.rs b/cli/src/generate/mod.rs
index 14c13aa4..48e747c9 100644
--- a/cli/src/generate/mod.rs
+++ b/cli/src/generate/mod.rs
@@ -15,7 +15,7 @@ mod grammars;
 mod nfa;
 mod node_types;
 mod npm_files;
-mod parse_grammar;
+pub mod parse_grammar;
 mod prepare_grammar;
 mod render;
 mod rules;
diff --git a/cli/src/generate/parse_grammar.rs b/cli/src/generate/parse_grammar.rs
index ce4b881a..feb560a9 100644
--- a/cli/src/generate/parse_grammar.rs
+++ b/cli/src/generate/parse_grammar.rs
@@ -64,8 +64,8 @@ enum RuleJSON {
 }
 
 #[derive(Deserialize)]
-struct GrammarJSON {
-    name: String,
+pub(crate) struct GrammarJSON {
+    pub(crate) name: String,
     rules: Map<String, Value>,
     conflicts: Option<Vec<Vec<String>>>,
     externals: Option<Vec<RuleJSON>>,
diff --git a/cli/src/lib.rs b/cli/src/lib.rs
index 19b82194..5d026cde 100644
--- a/cli/src/lib.rs
+++ b/cli/src/lib.rs
@@ -8,6 +8,7 @@ pub mod parse;
 pub mod properties;
 pub mod test;
 pub mod util;
+pub mod wasm;
 
 #[cfg(test)]
 mod tests;
diff --git a/cli/src/main.rs b/cli/src/main.rs
index a8b4fd8b..9decd720 100644
--- a/cli/src/main.rs
+++ b/cli/src/main.rs
@@ -5,7 +5,7 @@ use std::path::Path;
 use std::process::exit;
 use std::{u64, usize};
 use tree_sitter_cli::{
-    config, error, generate, highlight, loader, logger, parse, properties, test,
+    config, error, generate, highlight, loader, logger, parse, properties, test, wasm,
 };
 
 fn main() {
@@ -90,6 +90,11 @@ fn run() -> error::Result<()> {
                 .arg(Arg::with_name("html").long("html").short("h"))
                 .arg(Arg::with_name("time").long("time").short("t")),
         )
+        .subcommand(
+            SubCommand::with_name("build-wasm")
+                .about("Compile a parser to WASM")
+                .arg(Arg::with_name("path").index(1).multiple(true)),
+        )
         .get_matches();
 
     let home_dir = dirs::home_dir().expect("Failed to read home directory");
@@ -237,6 +242,9 @@ fn run() -> error::Result<()> {
                 )));
             }
         }
+    } else if let Some(matches) = matches.subcommand_matches("build-wasm") {
+        let grammar_path = current_dir.join(matches.value_of("path").unwrap_or(""));
+        wasm::compile_language_to_wasm(&grammar_path)?;
     }
 
     Ok(())
diff --git a/cli/src/wasm.rs b/cli/src/wasm.rs
new file mode 100644
index 00000000..1177391e
--- /dev/null
+++ b/cli/src/wasm.rs
@@ -0,0 +1,72 @@
+use super::error::{Error, Result};
+use super::generate::parse_grammar::GrammarJSON;
+use std::fs;
+use std::path::Path;
+use std::process::Command;
+
+pub fn compile_language_to_wasm(language_dir: &Path) -> Result<()> {
+    let src_dir = language_dir.join("src");
+    let grammar_json_path = src_dir.join("grammar.json");
+    let grammar_json = fs::read_to_string(&grammar_json_path).map_err(|e| {
+        format!(
+            "Failed to read grammar file {:?} - {}",
+            grammar_json_path, e
+        )
+    })?;
+    let grammar: GrammarJSON = serde_json::from_str(&grammar_json).map_err(|e| {
+        format!(
+            "Failed to parse grammar file {:?} - {}",
+            grammar_json_path, e
+        )
+    })?;
+
+    let mut command = Command::new("emcc");
+    command.args(&[
+        "-o",
+        &format!("tree-sitter-{}.wasm", grammar.name),
+        "-Os",
+        "-s",
+        "WASM=1",
+        "-s",
+        "SIDE_MODULE=1",
+        "-s",
+        &format!("EXPORTED_FUNCTIONS=[\"_tree_sitter_{}\"]", grammar.name),
+    ]);
+    command.arg("-I").arg(&src_dir);
+
+    // Find source files to compile
+    let entries = fs::read_dir(&src_dir)
+        .map_err(|e| format!("Failed to read source directory {:?} - {}", src_dir, e))?;
+
+    for entry in entries {
+        let entry = entry?;
+        let file_name = entry.file_name();
+
+        // Do not compile the node.js binding file.
+        if file_name
+            .to_str()
+            .map_or(false, |s| s.starts_with("binding"))
+        {
+            continue;
+        }
+
+        // Compile any .c, .cc, or .cpp files
+        if let Some(extension) = Path::new(&file_name).extension().and_then(|s| s.to_str()) {
+            if extension == "c" || extension == "cc" || extension == "cpp" {
+                command.arg(entry.path());
+            }
+        }
+    }
+
+    let output = command
+        .output()
+        .map_err(|e| format!("Failed to run emcc command - {}", e))?;
+    if output.status.success() {
+        Ok(())
+    } else {
+        Err(Error::from(format!(
+            "emcc command failed - {}",
+            String::from_utf8_lossy(&output.stderr)
+        )))
+    }
+}
diff --git a/lib/web/binding.c b/lib/web/binding.c
new file mode 100644
index 00000000..79fbd04d
--- /dev/null
+++ b/lib/web/binding.c
@@ -0,0 +1,221 @@
+#include <emscripten.h>
+#include <tree_sitter/api.h>
+#include <stdio.h>
+
+/*****************************/
+/* Section - Data marshaling */
+/*****************************/
+
+static const uint32_t INPUT_BUFFER_SIZE = 10 * 1024;
+
+const void *TRANSFER_BUFFER[12] = {
+  NULL, NULL, NULL, NULL,
+  NULL, NULL, NULL, NULL,
+  NULL, NULL, NULL, NULL,
+};
+
+void *ts_init() {
+  return TRANSFER_BUFFER;
+}
+
+static uint32_t code_unit_to_byte(uint32_t unit) {
+  return unit << 1;
+}
+
+static uint32_t byte_to_code_unit(uint32_t byte) {
+  return byte >> 1;
+}
+
+static void marshal_node(TSNode node) {
+  TRANSFER_BUFFER[0] = (const void *)node.id;
+  TRANSFER_BUFFER[1] = (const void *)node.context[0];
+  TRANSFER_BUFFER[2] = (const void *)node.context[1];
+  TRANSFER_BUFFER[3] = (const void *)node.context[2];
+  TRANSFER_BUFFER[4] = (const void *)node.context[3];
+}
+
+static TSNode unmarshal_node(const TSTree *tree) {
+  TSNode node;
+  node.id = TRANSFER_BUFFER[0];
+  node.context[0] = (uint32_t)TRANSFER_BUFFER[1];
+  node.context[1] = (uint32_t)TRANSFER_BUFFER[2];
+  node.context[2] = (uint32_t)TRANSFER_BUFFER[3];
+  node.context[3] = (uint32_t)TRANSFER_BUFFER[4];
+  node.tree = tree;
+  return node;
+}
+
+static void marshal_point(TSPoint point) {
+  TRANSFER_BUFFER[0] = (const void *)point.row;
+  TRANSFER_BUFFER[1] = (const void *)byte_to_code_unit(point.column);
+}
+
+static TSPoint unmarshal_point(const void **address) {
+  TSPoint point;
+  point.row = (uint32_t)address[0];
+  point.column = code_unit_to_byte((uint32_t)address[1]);
+  return point;
+}
+
+static TSInputEdit unmarshal_edit() {
+  TSInputEdit edit;
+  const void **address = TRANSFER_BUFFER;
+  edit.start_point = unmarshal_point(address); address += 2;
+  edit.old_end_point = unmarshal_point(address); address += 2;
+  edit.new_end_point = unmarshal_point(address); address += 2;
+  edit.start_byte = code_unit_to_byte((uint32_t)*address); address += 1;
+  edit.old_end_byte = code_unit_to_byte((uint32_t)*address); address += 1;
+  edit.new_end_byte = code_unit_to_byte((uint32_t)*address); address += 1;
+  return edit;
+}
+
+/********************/
+/* Section - Parser */
+/********************/
+
+extern void tree_sitter_parse_callback(
+  char *input_buffer,
+  uint32_t index,
+  uint32_t row,
+  uint32_t column,
+  uint32_t *length_read
+);
+
+extern void tree_sitter_log_callback(
+  void *payload,
+  TSLogType log_type,
+  const char *message
+);
+
+void ts_parser_new_wasm() {
+  TSParser *parser = ts_parser_new();
+  char *input_buffer = calloc(INPUT_BUFFER_SIZE, sizeof(char));
+  TRANSFER_BUFFER[0] = parser;
+  TRANSFER_BUFFER[1] = input_buffer;
+}
+
+static const char *call_parse_callback(
+  void *payload,
+  uint32_t byte,
+  TSPoint position,
+  uint32_t *bytes_read
+) {
+  char *buffer = (char *)payload;
+  tree_sitter_parse_callback(
+    buffer,
+    byte_to_code_unit(byte),
+    position.row,
+    byte_to_code_unit(position.column),
+    bytes_read
+  );
+  *bytes_read = code_unit_to_byte(*bytes_read);
+  if (*bytes_read > INPUT_BUFFER_SIZE) *bytes_read = INPUT_BUFFER_SIZE;
+  if (*bytes_read > 0) *bytes_read -= 2; // Remove null character
+  return buffer;
+}
+
+void ts_parser_enable_logger_wasm(TSParser *self, bool should_log) {
+  TSLogger logger = {self, should_log ? tree_sitter_log_callback : NULL};
+  ts_parser_set_logger(self, logger);
+}
+
+TSTree *ts_parser_parse_wasm(
+  TSParser *self,
+  char *input_buffer,
+  const TSTree *old_tree
+) {
+  TSInput input = {
+    input_buffer,
+    call_parse_callback,
+    TSInputEncodingUTF16
+  };
+  return ts_parser_parse(self, old_tree, input);
+}
+
+/******************/
+/* Section - Tree */
+/******************/
+
+void ts_tree_root_node_wasm(const TSTree *tree) {
+  marshal_node(ts_tree_root_node(tree));
+}
+
+void ts_tree_edit_wasm(TSTree *tree) {
+  TSInputEdit edit = unmarshal_edit();
+  ts_tree_edit(tree, &edit);
+}
+
+/******************/
+/* Section - Node */
+/******************/
+
+uint16_t ts_node_symbol_wasm(const TSTree *tree) {
+  TSNode node = unmarshal_node(tree);
+  return ts_node_symbol(node);
+}
+
+uint32_t ts_node_child_count_wasm(const TSTree *tree) {
+  TSNode node = unmarshal_node(tree);
+  return ts_node_child_count(node);
+}
+
+uint32_t ts_node_named_child_count_wasm(const TSTree *tree) {
+  TSNode node = unmarshal_node(tree);
+  return ts_node_named_child_count(node);
+}
+
+void ts_node_child_wasm(const TSTree *tree, uint32_t index) {
+  TSNode node = unmarshal_node(tree);
+  marshal_node(ts_node_child(node, index));
+}
+
+void ts_node_named_child_wasm(const TSTree *tree, uint32_t index) {
+  TSNode node = unmarshal_node(tree);
+  marshal_node(ts_node_named_child(node, index));
+}
+
+void ts_node_parent_wasm(const TSTree *tree) {
+  TSNode node = unmarshal_node(tree);
+  marshal_node(ts_node_parent(node));
+}
+
+void ts_node_descendant_for_position_wasm(const TSTree *tree) {
+  TSNode node = unmarshal_node(tree);
+  const void **address = TRANSFER_BUFFER + 5;
+  TSPoint start = unmarshal_point(address); address += 2;
+  TSPoint end = unmarshal_point(address);
+  marshal_node(ts_node_descendant_for_point_range(node, start, end));
+}
+
+void ts_node_named_descendant_for_position_wasm(const TSTree *tree) {
+  TSNode node = unmarshal_node(tree);
+  const void **address = TRANSFER_BUFFER + 5;
+  TSPoint start = unmarshal_point(address); address += 2;
+  TSPoint end = unmarshal_point(address);
+  marshal_node(ts_node_named_descendant_for_point_range(node, start, end));
+}
+
+void ts_node_start_point_wasm(const TSTree *tree) {
+  TSNode node = unmarshal_node(tree);
+  marshal_point(ts_node_start_point(node));
+}
+
+void ts_node_end_point_wasm(const TSTree *tree) {
+  TSNode node = unmarshal_node(tree);
+  marshal_point(ts_node_end_point(node));
+}
+
+uint32_t ts_node_start_index_wasm(const TSTree *tree) {
+  TSNode node = unmarshal_node(tree);
+  return byte_to_code_unit(ts_node_start_byte(node));
+}
+
+uint32_t ts_node_end_index_wasm(const TSTree *tree) {
+  TSNode node = unmarshal_node(tree);
+  return byte_to_code_unit(ts_node_end_byte(node));
+}
+
+char *ts_node_to_string_wasm(const TSTree *tree) {
+  TSNode node = unmarshal_node(tree);
+  return ts_node_string(node);
+}
diff --git a/lib/web/binding.js b/lib/web/binding.js
new file mode 100644
index 00000000..96d54407
--- /dev/null
+++ b/lib/web/binding.js
@@ -0,0 +1,367 @@
+const C = Module;
+const INTERNAL = {};
+const SIZE_OF_INT = 4;
+const SIZE_OF_NODE = 5 * SIZE_OF_INT;
+const SIZE_OF_POINT = 2 * SIZE_OF_INT;
+const SIZE_OF_RANGE = 2 * SIZE_OF_INT + 2 * SIZE_OF_POINT;
+
+var TRANSFER_BUFFER;
+var currentParseCallback;
+var currentLogCallback;
+
+class Parser {
+  static init() {
+    return new Promise(resolve => {
+      Module.onRuntimeInitialized = resolve
+    }).then(() => {
+      TRANSFER_BUFFER = C._ts_init();
+    });
+  }
+
+  constructor() {
+    C._ts_parser_new_wasm();
+    this[0] = getValue(TRANSFER_BUFFER, 'i32');
+    this[1] = getValue(TRANSFER_BUFFER + SIZE_OF_INT, 'i32');
+  }
+
+  delete() {
+    C._ts_parser_delete(this[0]);
+    C._free(this[1]);
+  }
+
+  setLanguage(language) {
+    this.language = language;
+    if (language.constructor !== Language) {
+      throw new Error('Argument must be a Language');
+    }
+    C._ts_parser_set_language(this[0], language[0]);
+    if (C._ts_parser_language(this[0]) !== language[0]) {
+      throw new Error('Incompatible language');
+    }
+  }
+
+  getLanguage() {
+    return this.language
+  }
+
+  setIncludedRanges(ranges) {
+    const buffer = C._calloc(ranges.length, SIZE_OF_RANGE);
+    let address = buffer;
+    for (let i = 0, n = ranges.length; i < n; i++) {
+      marshalRange(address, ranges[i]);
+      address += SIZE_OF_RANGE;
+    }
+    C._ts_parser_set_included_ranges(self[0], buffer, ranges.length);
+    C._free(buffer);
+  }
+
+  getIncludedRanges() {
+    const buffer = C._ts_parser_included_ranges(self[0], TRANSFER_BUFFER);
+    const length = getValue(TRANSFER_BUFFER, 'i32');
+    const result = new Array(length);
+    let address = buffer;
+    for (let i = 0; i < length; i++) {
+      result[i] = unmarshalRange(address);
+      address += SIZE_OF_RANGE;
+    }
+    return result;
+  }
+
+  parse(oldTree, callback) {
+    if (typeof callback === 'string') {
+      return this.parse(oldTree, index => callback.slice(index))
+    }
+
+    if (this.logCallback) {
+      currentLogCallback = this.logCallback;
+      C._ts_parser_enable_logger_wasm(this[0], 1);
+    } else {
+      C._ts_parser_enable_logger_wasm(this[0], 0);
+    }
+
+    currentParseCallback = callback;
+    const treeAddress = C._ts_parser_parse_wasm(
+      this[0],
+      this[1],
+      oldTree ? oldTree[0] : 0
+    );
+
+    currentParseCallback = null;
+    currentLogCallback = null;
+
+    if (!treeAddress) {
+      throw new Error('Parsing failed');
+    }
+
+    return new Tree(INTERNAL, treeAddress, this.language, callback);
+  }
+
+  reset() {
+    C._ts_parser_parse_wasm(this[0]);
+  }
+
+  setTimeoutMicros(timeout) {
+    C._ts_parser_set_timeout_micros(this[0], timeout);
+  }
+
+  getTimeoutMicros(timeout) {
+    C._ts_parser_timeout_micros(this[0]);
+  }
+
+  setLogger(callback) {
+    this.logCallback = callback;
+  }
+
+  getLogger() {
+    return this.logCallback;
+  }
+}
+
+class Tree {
+  constructor(internal, address, language, textCallback) {
+    if (internal !== INTERNAL) {
+      throw new Error('Illegal constructor')
+    }
+    this[0] = address;
+    this.language = language;
+    this.textCallback = textCallback;
+  }
+
+  copy() {
+    const address = C._ts_tree_copy(this[0]);
+    return new Tree(INTERNAL, address, this.language, this.textCallback);
+  }
+
+  delete() {
+    C._ts_tree_delete(this[0]);
+  }
+
+  edit(edit) {
+    marshalEdit(edit);
+    C._ts_tree_edit_wasm(this[0]);
+  }
+
+  get rootNode() {
+    C._ts_tree_root_node_wasm(this[0]);
+    return unmarshalNode(this);
+  }
+
+  getLanguage() {
+    return this.language;
+  }
+}
+
+class Node {
+  constructor(internal, tree) {
+    if (internal !== INTERNAL) {
+      throw new Error('Illegal constructor')
+    }
+    this.tree = tree;
+  }
+
+  get typeId() {
+    marshalNode(this);
+    return C._ts_node_symbol_wasm(this.tree);
+  }
+
+  get type() {
+    return this.tree.language.types[this.typeId] || 'ERROR';
+  }
+
+  get startPosition() {
+    marshalNode(this);
+    C._ts_node_start_point_wasm(this.tree[0]);
+    return unmarshalPoint(TRANSFER_BUFFER);
+  }
+
+  get endPosition() {
+    marshalNode(this);
+    C._ts_node_end_point_wasm(this.tree[0]);
+    return unmarshalPoint(TRANSFER_BUFFER);
+  }
+
+  get startIndex() {
+    marshalNode(this);
+    return C._ts_node_start_index_wasm(this.tree[0]);
+  }
+
+  get endIndex() {
+    marshalNode(this);
+    return C._ts_node_end_index_wasm(this.tree[0]);
+  }
+
+  get text() {
+    const startIndex = this.startIndex;
+    const length = this.endIndex - startIndex;
+    let result = this.tree.textCallback(startIndex);
+    while (result.length < length) {
+      result += this.tree.textCallback(startIndex + result.length);
+    }
+    return result.slice(0, length);
+  }
+
+  equals(other) {
+    if (this === other) return true;
+    for (let i = 0; i < 5; i++) {
+      if (this[i] !== other[i]) return false;
+    }
+    return true;
+  }
+
+  get childCount() {
+    marshalNode(this);
+    return C._ts_node_child_count_wasm(this.tree[0]);
+  }
+
+  child(index) {
+    marshalNode(this);
+    C._ts_node_child_wasm(this.tree[0], index);
+    return unmarshalNode(this.tree);
+  }
+
+  get namedChildCount() {
+    marshalNode(this);
+    return C._ts_node_named_child_count_wasm(this.tree[0]);
+  }
+
+  namedChild(index) {
+    marshalNode(this);
+    C._ts_node_named_child_wasm(this.tree[0], index);
+    return unmarshalNode(this.tree);
+  }
+
+  get parent() {
+    marshalNode(this);
+    C._ts_node_parent_wasm(this.tree[0]);
+    return unmarshalNode(this.tree);
+  }
+
+  descendantForPosition(start, end = start) {
+    marshalNode(this);
+    let address = TRANSFER_BUFFER + SIZE_OF_NODE;
+    marshalPoint(address);
+    marshalPoint(address + SIZE_OF_POINT);
+    C._ts_node_descendant_for_position_wasm(this.tree[0]);
+    return unmarshalNode(this.tree);
+  }
+
+  namedDescendantForPosition(start, end = start) {
+    marshalNode(this);
+    let address = TRANSFER_BUFFER + SIZE_OF_NODE;
+    marshalPoint(address, start);
+    marshalPoint(address + SIZE_OF_POINT, end);
+    C._ts_node_named_descendant_for_position_wasm(this.tree[0]);
+    return unmarshalNode(this.tree);
+  }
+
+  toString() {
+    marshalNode(this);
+    const address = C._ts_node_to_string_wasm(this.tree[0]);
+    const result = AsciiToString(address);
+    C._free(address);
+    return result;
+  }
+}
+
+class Language {
+  constructor(internal, address) {
+    if (internal !== INTERNAL) {
+      throw new Error('Illegal constructor')
+    }
+    this[0] = address;
+    this.types = new Array(C._ts_language_symbol_count(this[0]));
+    for (let i = 0, n = this.types.length; i < n; i++) {
+      if (C._ts_language_symbol_type(this[0], i) < 2) {
+        this.types[i] = UTF8ToString(C._ts_language_symbol_name(this[0], i));
+      }
+    }
+  }
+
+  get version() {
+    return C._ts_language_version(this[0]);
+  }
+
+  static load(url) {
+    return fetch(url)
+      .then(response => response.arrayBuffer()
+        .then(buffer => {
+          if (response.ok) {
+            return loadWebAssemblyModule(new Uint8Array(buffer), {loadAsync: true});
+          } else {
+            const body = new TextDecoder('utf-8').decode(buffer);
+            throw new Error(`Language.load failed with status ${response.status}.\n\n${body}`)
+          }
+        }))
+      .then(exports => {
+        const functionName = Object.keys(exports).find(key => key.includes("tree_sitter_"));
+        const languageAddress = exports[functionName]();
+        return new Language(INTERNAL, languageAddress);
+      });
+  }
+}
+
+function marshalNode(node) {
+  let address = TRANSFER_BUFFER;
+  for (let i = 0; i < 5; i++) {
+    setValue(address, node[i], 'i32');
+    address += SIZE_OF_INT;
+  }
+}
+
+function unmarshalNode(tree) {
+  let address = TRANSFER_BUFFER;
+  const id = getValue(address, 'i32');
+  if (id === 0) return null;
+  const result = new Node(INTERNAL, tree);
+  result[0] = id;
+  address += SIZE_OF_INT;
+  for (let i = 1; i < 5; i++) {
+    result[i] = getValue(address, 'i32');
+    address += SIZE_OF_INT;
+  }
+  return result;
+}
+
+function marshalPoint(address, point) {
+  setValue(address, point.row, 'i32')
+  setValue(address + SIZE_OF_INT, point.column, 'i32')
+}
+
+function unmarshalPoint(address) {
+  return {
+    row: getValue(address, 'i32'),
+    column: getValue(address + SIZE_OF_INT, 'i32')
+  }
+}
+
+function marshalRange(address, range) {
+  setValue(address, range.startIndex, 'i32'); address += SIZE_OF_INT;
+  setValue(address, range.endIndex, 'i32'); address += SIZE_OF_INT;
+  marshalPoint(address, range.startPosition); address += SIZE_OF_POINT;
+  marshalPoint(address, range.endPosition); address += SIZE_OF_POINT;
+}
+
+function unmarshalRange(address) {
+  const result = {};
+  result.startIndex = getValue(address, 'i32'); address += SIZE_OF_INT;
+  result.endIndex = getValue(address, 'i32'); address += SIZE_OF_INT;
+  result.startPosition = unmarshalPoint(address); address += SIZE_OF_POINT;
+  result.endPosition = unmarshalPoint(address);
+  return result;
+}
+
+function marshalEdit(edit) {
+  let address = TRANSFER_BUFFER;
+  marshalPoint(address, edit.startPosition); address += SIZE_OF_POINT;
+  marshalPoint(address, edit.oldEndPosition); address += SIZE_OF_POINT;
+  marshalPoint(address, edit.newEndPosition); address += SIZE_OF_POINT;
+  setValue(address, edit.startIndex, 'i32'); address += SIZE_OF_INT;
+  setValue(address, edit.oldEndIndex, 'i32'); address += SIZE_OF_INT;
+  setValue(address, edit.newEndIndex, 'i32'); address += SIZE_OF_INT;
+}
+
+Parser.Language = Language;
+
+return Parser;
+
+}));
diff --git a/lib/web/imports.js b/lib/web/imports.js
new file mode 100644
index 00000000..b9bca74e
--- /dev/null
+++ b/lib/web/imports.js
@@ -0,0 +1,21 @@
+mergeInto(LibraryManager.library, {
+  tree_sitter_parse_callback: function(
+    inputBufferAddress,
+    index,
+    row,
+    column,
+    lengthAddress
+  ) {
+    var INPUT_BUFFER_SIZE = 10 * 1024;
+    var string = currentParseCallback(index, {row: row, column: column});
+    setValue(lengthAddress, string.length, 'i32');
+    stringToUTF16(string, inputBufferAddress, INPUT_BUFFER_SIZE);
+  },
+
+  tree_sitter_log_callback: function(_payload, isLexMessage, messageAddress) {
+    if (currentLogCallback) {
+      const message = UTF8ToString(messageAddress);
+      currentLogCallback(isLexMessage, message);
+    }
+  }
+});
diff --git a/lib/web/prefix.js b/lib/web/prefix.js
new file mode 100644
index 00000000..b380d814
--- /dev/null
+++ b/lib/web/prefix.js
@@ -0,0 +1,11 @@
+(function (root, factory) {
+  if (typeof define === 'function' && define.amd) {
+    define([], factory);
+  } else if (typeof exports === 'object') {
+    module.exports = factory();
+    module.exports.init();
+    delete module.exports.init;
+  } else {
+    window.TreeSitter = factory();
+  }
+}(this, function () {
diff --git a/script/build-wasm b/script/build-wasm
new file mode 100755
index 00000000..09860e5d
--- /dev/null
+++ b/script/build-wasm
@@ -0,0 +1,31 @@
+#!/usr/bin/env bash
+
+export EMCC_FORCE_STDLIBS=libc++
+
+args="-Os"
+target_dir="target/release"
+if [[ "$1" == "--debug" ]]; then
+  args="-s SAFE_HEAP=1 -O0"
+  target_dir="target/debug"
+fi
+
+mkdir -p $target_dir
+
+emcc                                \
+  -s WASM=1                         \
+  -s ALLOW_MEMORY_GROWTH            \
+  -s MAIN_MODULE=1                  \
+  -s ASSERTIONS=1                   \
+  -s EXPORT_ALL=1                   \
+  $args                             \
+  -std=c99                          \
+  -D 'fprintf(...)='                \
+  -I lib/src                        \
+  -I lib/include                    \
+  -I lib/utf8proc                   \
+  --js-library lib/web/imports.js   \
+  --pre-js lib/web/prefix.js        \
+  --post-js lib/web/binding.js      \
+  lib/src/lib.c                     \
+  lib/web/binding.c                 \
+  -o $target_dir/tree-sitter.js