diff --git a/README.md b/README.md
index b801253ea..5a6a891f6 100644
--- a/README.md
+++ b/README.md
@@ -38,8 +38,8 @@ The following core Node.js modules (v8.7.0+) have been implemented:
 | [path](https://nodejs.org/api/path.html)                     | :heavy_check_mark: |
 | [process](https://nodejs.org/api/process.html)               | :heavy_check_mark: |
 | [querystring](https://nodejs.org/api/querystring.html)       | :heavy_check_mark: |
-| [readline](https://nodejs.org/api/readline.html)             |                    |
-| [repl](https://nodejs.org/api/repl.html)                     |                    |
+| [readline](https://nodejs.org/api/readline.html)             | :heavy_check_mark: |
+| [repl](https://nodejs.org/api/repl.html)                     | :heavy_check_mark: |
 | [stream](https://nodejs.org/api/stream.html)                 |                    |
 | [string-decoder](https://nodejs.org/api/string_decoder.html) | :heavy_check_mark: |
 | [timers](https://nodejs.org/api/timers.html)                 | :heavy_check_mark: |
diff --git a/app/current/src/main/scala/io/scalajs/nodejs/readline/Interface.scala b/app/current/src/main/scala/io/scalajs/nodejs/readline/Interface.scala
index 80a6e6e98..99b434604 100644
--- a/app/current/src/main/scala/io/scalajs/nodejs/readline/Interface.scala
+++ b/app/current/src/main/scala/io/scalajs/nodejs/readline/Interface.scala
@@ -51,7 +51,7 @@ trait Interface extends IEventEmitter {
     * If output is set to null or undefined when calling createInterface, nothing is displayed.
     * @example rl.question(query, callback)
     */
-  def question(query: String, callback: js.Function): Unit = js.native
+  def question(query: String, callback: js.Function1[String, Any]): Unit = js.native
 
   /**
     * Resumes the readline input stream.
@@ -71,7 +71,7 @@ trait Interface extends IEventEmitter {
     * This will also resume the input stream if it has been paused.
     * @example rl.write(data[, key])
     */
-  def write(data: String, key: js.Any): Unit = js.native
+  def write(data: String, key: Key): Unit = js.native
 
   /**
     * Writes data to output stream, unless output is set to null or undefined when calling createInterface.
@@ -81,8 +81,16 @@ trait Interface extends IEventEmitter {
     */
   def write(data: String): Unit = js.native
 
+  // TODO: [Symbol.asyncIterator]()
 }
 
+class Key(
+    var ctrl: js.UndefOr[Boolean] = js.undefined,
+    var meta: js.UndefOr[Boolean] = js.undefined,
+    var shift: js.UndefOr[Boolean] = js.undefined,
+    var name: js.UndefOr[String] = js.undefined
+) extends js.Object
+
 /**
   * Readline Interface Companion
   */
diff --git a/app/current/src/main/scala/io/scalajs/nodejs/readline/Readline.scala b/app/current/src/main/scala/io/scalajs/nodejs/readline/Readline.scala
index e0349e9a4..b6e857cd2 100644
--- a/app/current/src/main/scala/io/scalajs/nodejs/readline/Readline.scala
+++ b/app/current/src/main/scala/io/scalajs/nodejs/readline/Readline.scala
@@ -1,12 +1,13 @@
 package io.scalajs.nodejs.readline
 
 import io.scalajs.nodejs.events.IEventEmitter
+import io.scalajs.nodejs.stream.{Readable, Writable}
 
 import scala.scalajs.js
 import scala.scalajs.js.annotation.JSImport
 
-/**
-  * Readline allows reading of a stream (such as process.stdin) on a line-by-line basis.
+/**reading
+  * Readline allows  of a stream (such as process.stdin) on a line-by-line basis.
   * To use this module, do require('readline').
   * Note that once you've invoked this module, your Node.js program will not terminate until you've closed the interface.
   * @see https://nodejs.org/api/readline.html
@@ -23,13 +24,13 @@ trait Readline extends IEventEmitter {
     * </ul>
     * @example readline.clearLine(stream, dir)
     */
-  def clearLine(stream: js.Any, dir: Int): Unit = js.native
+  def clearLine(stream: Writable, dir: Int, callback: js.Function = js.native): Boolean = js.native
 
   /**
     * Clears the screen from the current position of the cursor down.
     * @example readline.clearScreenDown(stream)
     */
-  def clearScreenDown(stream: js.Any): Unit = js.native
+  def clearScreenDown(stream: Writable, callback: js.Function = js.native): Boolean = js.native
 
   /**
     * Creates a readline Interface instance.
@@ -41,13 +42,17 @@ trait Readline extends IEventEmitter {
     * Move cursor to the specified position in a given TTY stream.
     * @example readline.cursorTo(stream, x, y)
     */
-  def cursorTo(stream: js.Any, x: Int, y: Int): Unit = js.native
+  def cursorTo(stream: Writable, x: Int, y: Int, callback: js.Function = js.native): Unit = js.native
+  def cursorTo(stream: Writable, x: Int, callback: js.Function): Unit                     = js.native
+  def cursorTo(stream: Writable, x: Int): Unit                                            = js.native
+
+  def emitKeypressEvents(stream: Readable, interface: Interface = js.native): Unit = js.native
 
   /**
     * Move cursor relative to it's current position in a given TTY stream.
     * @example readline.moveCursor(stream, dx, dy)
     */
-  def moveCursor(stream: js.Any, dx: Int, dy: Int): Unit = js.native
+  def moveCursor(stream: Writable, dx: Int, dy: Int, callback: js.Function = js.native): Unit = js.native
 
 }
 
diff --git a/app/current/src/main/scala/io/scalajs/nodejs/readline/ReadlineOptions.scala b/app/current/src/main/scala/io/scalajs/nodejs/readline/ReadlineOptions.scala
index e1582ff97..59601cece 100644
--- a/app/current/src/main/scala/io/scalajs/nodejs/readline/ReadlineOptions.scala
+++ b/app/current/src/main/scala/io/scalajs/nodejs/readline/ReadlineOptions.scala
@@ -7,9 +7,14 @@ import scala.scalajs.js
 /**
   * Readline Options
   */
-class ReadlineOptions(var input: js.UndefOr[Readable] = js.undefined,
-                      var output: js.UndefOr[Writable] = js.undefined,
-                      var completer: js.UndefOr[js.Function] = js.undefined,
-                      var terminal: js.UndefOr[Boolean] = js.undefined,
-                      var historySize: js.UndefOr[Int] = js.undefined)
-    extends js.Object
+class ReadlineOptions(
+    var input: js.UndefOr[Readable] = js.undefined,
+    var output: js.UndefOr[Writable] = js.undefined,
+    var completer: js.UndefOr[js.Function] = js.undefined,
+    var terminal: js.UndefOr[Boolean] = js.undefined,
+    var historySize: js.UndefOr[Int] = js.undefined,
+    var prompt: js.UndefOr[String] = js.undefined,
+    var crlfDelay: js.UndefOr[Double] = js.undefined,
+    var removeHistoryDuplicates: js.UndefOr[Boolean] = js.undefined,
+    var escapeCodeTimeout: js.UndefOr[Double] = js.undefined
+) extends js.Object
diff --git a/app/current/src/main/scala/io/scalajs/nodejs/repl/REPL.scala b/app/current/src/main/scala/io/scalajs/nodejs/repl/REPL.scala
index 427d90973..8695e0782 100644
--- a/app/current/src/main/scala/io/scalajs/nodejs/repl/REPL.scala
+++ b/app/current/src/main/scala/io/scalajs/nodejs/repl/REPL.scala
@@ -1,7 +1,7 @@
 package io.scalajs.nodejs.repl
 
 import io.scalajs.nodejs.events.IEventEmitter
-import io.scalajs.nodejs.net.Socket
+import io.scalajs.nodejs.stream
 
 import scala.scalajs.js
 import scala.scalajs.js.annotation.JSImport
@@ -13,32 +13,31 @@ import scala.scalajs.js.annotation.JSImport
   */
 @js.native
 trait REPL extends IEventEmitter {
-  var REPL_MODE_SLOPPY: String = js.native
-  var REPL_MODE_STRICT: String = js.native
-  var REPL_MODE_MAGIC: String  = js.native
+  var REPL_MODE_SLOPPY: js.Symbol = js.native
+  var REPL_MODE_STRICT: js.Symbol = js.native
 
-  /**
-    * @example repl.start([options])
-    */
-  def start(options: REPLOptions): REPLServer = js.native
-
-  /**
-    * @example repl.start([options])
-    */
-  def start(prompt: String, socket: Socket): REPLServer = js.native
-
-  /**
-    * @example repl.start([options])
-    */
-  def start(prompt: String): REPLServer = js.native
-
-  /**
-    * @example repl.start([options])
-    */
-  def start(): REPLServer = js.native
+  @deprecated("Use REPL_MODE_SLOPPY instead", "Node.js v6.0.0")
+  var REPL_MODE_MAGIC: js.UndefOr[js.Symbol] = js.native
 
+  def start(options: StartOptions = js.native): REPLServer = js.native
+  def start(prompt: String): REPLServer                    = js.native
 }
 
+class StartOptions(
+    var prompt: js.UndefOr[String] = js.undefined,
+    var input: js.UndefOr[stream.Readable] = js.undefined,
+    var output: js.UndefOr[stream.Writable] = js.undefined,
+    var terminal: js.UndefOr[Boolean] = js.undefined,
+    var eval: js.UndefOr[js.Function4[String, js.Object, String, js.Function, Any]] = js.undefined,
+    var useColors: js.UndefOr[Boolean] = js.undefined,
+    var useGlobal: js.UndefOr[Boolean] = js.undefined,
+    var ignoreUndefined: js.UndefOr[Boolean] = js.undefined,
+    var writer: js.UndefOr[js.Function1[js.Any, Any]] = js.undefined,
+    var completer: js.UndefOr[js.Function] = js.undefined,
+    var replMode: js.UndefOr[js.Symbol] = js.undefined,
+    var breakEvalOnSigint: js.UndefOr[Boolean] = js.undefined
+) extends js.Object
+
 /**
   * REPL Singleton
   */
diff --git a/app/current/src/main/scala/io/scalajs/nodejs/repl/REPLServer.scala b/app/current/src/main/scala/io/scalajs/nodejs/repl/REPLServer.scala
index c5763e438..41c804b28 100644
--- a/app/current/src/main/scala/io/scalajs/nodejs/repl/REPLServer.scala
+++ b/app/current/src/main/scala/io/scalajs/nodejs/repl/REPLServer.scala
@@ -1,9 +1,11 @@
 package io.scalajs.nodejs.repl
 
+import com.thoughtworks.enableIf
 import io.scalajs.nodejs.events.IEventEmitter
 import io.scalajs.nodejs.readline.Interface
 
 import scala.scalajs.js
+import scala.scalajs.js.|
 
 /**
   * REPL Server
@@ -16,6 +18,9 @@ trait REPLServer extends IEventEmitter with Interface {
     */
   val context: REPLContext = js.native
 
+  @enableIf(io.scalajs.nodejs.CompilerSwitches.gteNodeJs10)
+  def clearBufferedCommand(): Unit = js.native
+
   /**
     * The replServer.defineCommand() method is used to add new .-prefixed commands to the REPL instance.
     * Such commands are invoked by typing a period (.) followed by the keyword. The cmd is either a Function
@@ -27,7 +32,7 @@ trait REPLServer extends IEventEmitter with Interface {
     * @param keyword The command keyword (without a leading . character).
     * @param cmd     The function to invoke when the command is processed.
     */
-  def defineCommand(keyword: String, cmd: js.Function0[Any]): Unit = js.native
+  def defineCommand(keyword: String, cmd: DefinedCommand | js.Function1[String, Any]): Unit = js.native
 
   /**
     * The replServer.displayPrompt() method readies the REPL instance for input from the user, printing the
@@ -52,8 +57,16 @@ trait REPLServer extends IEventEmitter with Interface {
     */
   def displayPrompt(): Unit = js.native
 
+  @enableIf(io.scalajs.nodejs.CompilerSwitches.gteNodeJs12)
+  def setupHistory(historyPath: String, callback: js.Function2[io.scalajs.nodejs.Error, REPLServer, Any]): Unit =
+    js.native
 }
 
+class DefinedCommand(
+    var action: js.Function1[String, Any],
+    var help: js.UndefOr[String] = js.undefined
+) extends js.Object
+
 /**
   * REPL Server Companion
   */
diff --git a/app/current/src/main/scala/io/scalajs/nodejs/repl/package.scala b/app/current/src/main/scala/io/scalajs/nodejs/repl/package.scala
index 081ddc5c3..823a519e6 100644
--- a/app/current/src/main/scala/io/scalajs/nodejs/repl/package.scala
+++ b/app/current/src/main/scala/io/scalajs/nodejs/repl/package.scala
@@ -25,7 +25,7 @@ package object repl {
       * @param listener The listener callback
       */
     @inline
-    def onExit(listener: () => Any): server.type = server.on("exit", listener)
+    def onExit(listener: () => Any): REPLServer = server.on("exit", listener)
 
     /**
       * The 'reset' event is emitted when the REPL's context is reset. This occurs whenever the .clear command
@@ -35,7 +35,7 @@ package object repl {
       * @param listener The listener callback
       */
     @inline
-    def onReset(listener: REPLContext => Any): server.type = server.on("reset", listener)
+    def onReset(listener: REPLContext => Any): REPLServer = server.on("reset", listener)
 
   }
 
@@ -47,7 +47,7 @@ package object repl {
     * <li>NODE_REPL_MODE</li>
     * </ul>
     */
-  final implicit class EnvironmentVariableOptions(val env: process.Environment) extends AnyVal {
+  final implicit class EnvironmentVariableOptions(private val env: process.Environment) extends AnyVal {
 
     /**
       * When a valid path is given, persistent REPL history will be saved to the specified file rather