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Capture user input in Minecraft through an anvil GUI in under 20 lines of code


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AnvilGUI is a library to capture user input in Minecraft through an anvil inventory. Anvil inventories within the realm of the Minecraft / Bukkit / Spigot / Paper API are extremely finnicky and ultimately don't support the ability to use them fully for the task of user input. As a result, the only way to achieve user input with an anvil inventory requires interaction with obfuscated, decompiled code. AnvilGUI provides a straightforward, versatile, and easy-to-use solution without having your project depend on version specific code.


Java 8 and Bukkit / Spigot. Most server versions in the Spigot Repository are supported.

My version isn't supported

If you are a developer, submit a pull request adding a wrapper module for your version. Otherwise, please create an issue on the issues tab.


As a dependency

AnvilGUI requires the usage of Maven or a Maven compatible build system.



It is best to be a good citizen and relocate the dependency to within your namespace in order to prevent conflicts with other plugins. Here is an example of how to relocate the dependency:

            <version>${shade.version}</version> <!-- The version must be at least 3.5.0 -->
                                <shadedPattern>[YOUR_PLUGIN_PACKAGE].anvilgui</shadedPattern> <!-- Replace [YOUR_PLUGIN_PACKAGE] with your namespace -->

Note: In order to solve <minimizeJar> removing AnvilGUI VerionWrappers from the final jar and making the library unusable, ensure that your <filters> section contains the example <filter> as seen above.

In your plugin

The AnvilGUI.Builder class is how you build an AnvilGUI. The following methods allow you to modify various parts of the displayed GUI. Javadocs are available here.


Takes a Consumer<StateSnapshot> argument that is called when a player closes the anvil gui.

builder.onClose(stateSnapshot -> {
    stateSnapshot.getPlayer().sendMessage("You closed the inventory.");

onClick(BiFunction<Integer, AnvilGUI.StateSnapshot, AnvilGUI.ResponseAction>)

Takes a BiFunction with the slot that was clicked and a snapshot of the current gui state. The function is called when a player clicks any slots in the inventory. You must return a List<AnvilGUI.ResponseAction>, which could include:

  • Closing the inventory (AnvilGUI.ResponseAction.close())
  • Replacing the input text (AnvilGUI.ResponseAction.replaceInputText(String))
  • Updating the title of the inventory (AnvilGUI.ResponseAction.updateTitle(String, boolean))
  • Opening another inventory (AnvilGUI.ResponseAction.openInventory(Inventory))
  • Running generic code (
  • Nothing! (Collections.emptyList())

The list of actions are ran in the order they are supplied.

builder.onClick((slot, stateSnapshot) -> {
    if (slot != AnvilGUI.Slot.OUTPUT) {
        return Collections.emptyList();

    if (stateSnapshot.getText().equalsIgnoreCase("you")) {
        stateSnapshot.getPlayer().sendMessage("You have magical powers!");
        return Arrays.asList(
   -> myCode(stateSnapshot.getPlayer()))
    } else {
        return Arrays.asList(AnvilGUI.ResponseAction.replaceInputText("Try again"));


Takes a ClickHandler, a shorthand for BiFunction<Integer, AnvilGui.StateSnapshot, CompletableFuture<AnvilGUI.ResponseAction>>, that behaves exactly like onClick() with the difference that it returns a CompletableFuture and therefore allows for asynchronous calculation of the ResponseActions.

builder.onClickAsync((slot, stateSnapshot) -> CompletedFuture.supplyAsync(() -> {
    // this code is now running async
    if (slot != AnvilGUI.Slot.OUTPUT) {
        return Collections.emptyList();

    if (database.isMagical(stateSnapshot.getText())) {
        // the `ResponseAction`s will run on the main server thread
        return Arrays.asList(
   -> myCode(stateSnapshot.getPlayer()))
    } else {
        return Arrays.asList(AnvilGUI.ResponseAction.replaceInputText("Try again"));


Tells the AnvilGUI to disable the mechanism that is put into place to prevent concurrent execution of the click handler set by onClickAsync(ClickHandler).


interactableSlots(int... slots)

This allows or denies users to take / input items in the anvil slots that are provided. This feature is useful when you try to make a inputting system using an anvil gui.

builder.interactableSlots(Slot.INPUT_LEFT, Slot.INPUT_RIGHT);


Tells the AnvilGUI to prevent the user from pressing escape to close the inventory. Useful for situations like password input to play.



This toggles compatibility with Geyser software, specifically being able to use AnvilGUI with 0 experience level on Bedrock. Enabled by default.



Takes a String that contains what the initial text in the renaming field should be set to. If itemLeft is provided, then the display name is set to the provided text. If no itemLeft is set, then a piece of paper will be used.

builder.text("What is the meaning of life?");


Takes a custom ItemStack to be placed in the left input slot.

ItemStack stack = new ItemStack(Material.IRON_SWORD);
ItemMeta meta = stack.getItemMeta();
meta.setLore(Arrays.asList("Sharp iron sword"));


Takes a custom ItemStack to be placed in the right input slot.

ItemStack stack = new ItemStack(Material.IRON_INGOT);
ItemMeta meta = stack.getItemMeta();
meta.setLore(Arrays.asList("A piece of metal"));


Takes a String that will be used literally as the inventory title. Only displayed in Minecraft 1.14 and above.

builder.title("Enter your answer");


Takes a String which contains rich text components serialized as JSON. Useful for settings titles with hex color codes or Adventure Component interop. Only displayed in Minecraft 1.14 and above.

builder.jsonTitle("{\"text\":\"Enter your answer\",\"color\":\"green\"}")


Takes the Plugin object that is making this anvil gui. It is needed to register listeners.



Takes an Executor that must execute on the main server thread. If the main server thread is not accessible via the Bukkit scheduler, like on Folia servers, it can be swapped for a Folia aware executor.



Takes a Player that the anvil gui should be opened for. This method can be called multiple times without needing to create a new AnvilGUI.Builder object.;

A Common Use Case Example

new AnvilGUI.Builder()
    .onClose(stateSnapshot -> {
        stateSnapshot.getPlayer().sendMessage("You closed the inventory.");
    .onClick((slot, stateSnapshot) -> { // Either use sync or async variant, not both
        if(slot != AnvilGUI.Slot.OUTPUT) {
            return Collections.emptyList();

        if(stateSnapshot.getText().equalsIgnoreCase("you")) {
            stateSnapshot.getPlayer().sendMessage("You have magical powers!");
            return Arrays.asList(AnvilGUI.ResponseAction.close());
        } else {
            return Arrays.asList(AnvilGUI.ResponseAction.replaceInputText("Try again"));
    .preventClose()                                                    //prevents the inventory from being closed
    .text("What is the meaning of life?")                              //sets the text the GUI should start with
    .title("Enter your answer.")                                       //set the title of the GUI (only works in 1.14+)
    .plugin(myPluginInstance)                                          //set the plugin instance
    .open(myPlayer);                                                   //opens the GUI for the player provided


We use Maven to handle our dependencies. Run mvn clean install using Java 21 to build the project.


The project utilizes the Spotless Maven Plugin to enforce style guidelines. You will not be able to build the project if your code does not meet the guidelines. To fix all code formatting issues, simply run mvn spotless:apply.


This project is licensed under the MIT License.