Builtins overview

Builtins are functions and events the runtime provides. They're the bridge between your script and the world it runs in — game memory, the framebuffer, the network, the gamepad.

How to read a signature

Signatures on these pages use Munos type annotations:

draw_image(img: image, pal: u32[], x: i32, y: i32, flip_x: bool = false)

• A trailing = value is a default; the argument may be omitted.
• A trailing : type after the parameter list is the return type; its absence means the builtin returns nothing.
• Each builtin notes its role — client, server, or either. Calling one in the wrong role is a compile error.

The groups

Group	What's in it
Memory	read_u8 … read_i32, write_u8 … write_i32
Images & drawing	image_literal, image_from_bytes, image_from_bitmap_bytes, image_from_png_bytes, palette_from_png_bytes, draw_image
Networking & packing	send, event receive, pack, unpack, base64_decode, string_from_bytes
Input	event input, input_held, input_pressed, consume_input
ROM control	pause_rom, resume_rom, local_rom_hash, disconnect
Server & slots	slot, max_clients, tick_rate, set_tick_rate, hop, redirect, connection events
Instances	spawn, find_instance, list_instances, player_count, tell, my_url, instance_url, uuid, list_scripts, shard_config, list_shards
Persistence	db_get, db_set, db_del, db_list, event db_error
Fetch	fetch, event fetch_error
Misc	print, len, size, copy, push, pop, casts

Special forms

A few call-shaped features aren't ordinary builtins — they're compiler forms:

• Casts — i8(x) … u32(x). See Types.
• print — variadic; accepts any number of printable arguments.
• len / size / copy / push / pop — operate on arrays (and len on strings). See Arrays.

These are covered on the Misc page.