diff --git a/README.md b/README.md
index 2d64ff1..84d2a53 100644
--- a/README.md
+++ b/README.md
@@ -99,6 +99,9 @@ where it enables scripting for IoT devices.
   <dd>Perform garbage collection. If `full` is `true`, reclaim RAM to OS.</dd>
 </dl>
 
+There are TypeScript-typings ([mjs.d.ts](./mjs.d.ts))
+with all these mJS builtins.
+
 # C/C++ interoperability
 
 mJS requires no glue code. The mJS's Foreign Function Interface (FFI)
diff --git a/jsconfig.json b/jsconfig.json
new file mode 100644
index 0000000..0b5a72f
--- /dev/null
+++ b/jsconfig.json
@@ -0,0 +1,6 @@
+{
+  "compilerOptions": {
+    "noLib": true,
+    "module": "None"
+  }
+}
\ No newline at end of file
diff --git a/mjs.d.ts b/mjs.d.ts
new file mode 100644
index 0000000..eb64f7d
--- /dev/null
+++ b/mjs.d.ts
@@ -0,0 +1,112 @@
+/**
+ * Print arguments to stdout, separated by space.
+ */
+declare function print(...args: any): void;
+
+/**
+ * Execute specified file.
+ * @param file a `.js` file path
+ * @param globalNamespace global namespace object. If not specified,
+ *  a current global namespace is passed to the script, which allows `file`
+ *  to modify the current namespace.
+ */
+declare function load(path: string, globalNamespace?: object): any;
+
+/**
+ * Exit interpreter with the given error message
+ */
+declare function die(errorMessage: string): never;
+
+/**
+ * Return numeric byte value at given string index.
+ * @param asciiCode must be in range `0-255` (inclusive)
+ * @returns 1-byte string (or `null` if asciiCode is incorrect)
+ * @example chr(0x61) === 'a';
+ */
+declare function chr(asciiCode: number): string | null;
+
+/**
+ * Create a string backed by a C memory chunk.
+ * A returned string starts at memory location `ptrValue`,
+ * and is `length` bytes long.
+ */
+declare function mkstr(ptrValue: unknown, length: number): string;
+
+/**
+ * Like `mkstr(ptrValue, length)`, but the returned string starts at
+ * memory location `ptrValue + offset`, and the caller can specify
+ * whether the string needs to be copied to the internal mjs buffer.
+ * By default it's not copied.
+ */
+declare function mkstr(ptrValue: unknown, offset: number, length: number, copy: boolean = false): string;
+
+/**
+ * Import native C function into mJS.
+ */
+declare function ffi(nativeSignature: string): (...args: any) => any;
+
+/**
+ * Perform garbage collection.
+ * @param full if `true`, reclaim RAM to OS.
+ */
+declare function gc(full: boolean): void;
+
+declare namespace JSON {
+  /**
+   * Parse JSON string and return parsed value.
+   */
+  export function parse(jsonString: string): any;
+
+  /**
+   * Get string representation of the mJS value.
+   */
+  export function stringify(jsValue: any): string;
+}
+
+declare namespace Object {
+  /**
+   * Create an object with the provided prototype.
+   * @example let proto = {foo: 1}; let o = Object.create(proto);
+   */
+  export function create(prototype: object): object;
+}
+
+interface String {
+  /**
+   * Return a substring between two indices.
+   * @example 'abcdef'.slice(1,3) === 'bc';
+   */
+  slice(start: number, end: number): string;
+
+  /**
+   * Return numeric byte value at given string index.
+   * @example 'abc'.at(0) === 0x61;
+   */
+  at(index: number): number;
+
+  /**
+   * Return index of first occurrence of substr within the string.
+   * @returns index or `-1` if not found.
+   * @example 'abc'.indexOf('bc') === 1;
+   */
+  indexOf(substring: string): number;
+}
+
+interface Array<T> {
+  /**
+   * Change the contents of an array by removing existing elements
+   * and/or adding new elements.
+   * @example let a = [1,2,3,4,5]; a.splice(1, 2, 100, 101, 102); a === [1,100,101,102,4,5];
+   */
+  splice(startIndex: number, deleteCount: number, ...insertElements?: any): T[];
+}
+
+/*
+Recommended VSCode settings (.vscode/settings.json):
+{
+  "typescript.suggest.autoImports": false,
+  "javascript.suggest.autoImports": false,
+  "typescript.suggest.includeAutomaticOptionalChainCompletions": false,
+  "javascript.suggest.includeAutomaticOptionalChainCompletions": false,
+}
+*/