Chat

Minecraft supports two-way chat communication via the Chat Message packet, which support a variety of formatting options. Note that this system isn't exclusive to the Chat Message packet - it's used in several other places (including written books, death messages, window titles, and the like).

Current system (JSON Chat)

Chat data is sent in JSON. For most situations, the JSON is strictly parsed, but lenient JSON parsing is used for the Disconnect packet and for written book text.

Inheritance

Each component can have multiple siblings. Each sibling component inherits properties from the style of its parent, using those styles if they are not defined in the sibling's own style.

For example, in this component:

{
    "text": "foo",
    "bold": "true",
    "extra": [
    {
        "text": "bar"
    },
    {
        "text": "baz",
        "bold": "false"
    },
    {
        "text": "qux",
        "bold": "true"
    }]
}

The text "foo", "bar", and "qux" are all rendered as bold while "baz" is not.

Schema

Each situation where a component can appear may be either a JSON object (the most common choice), an array, or a JSON primitive (which is converted to a String).

JSON primitives can be used for components, in which case they are implicitly converted into a String component. Note that it is invalid to have a JSON primitive as the root object, so it is not valid to merely send the text in quotes. This shorthand is useful for sibling lists, though.

It is also legal to put a JSON array where a component would go, so long as the array is not empty. The first component in the array is the parent of all of the following components. This can produce unusual behavior with style inheritance, but it is still useful shorthand.

The most common type of component is a JSON object; the format is as follows:

Shared between all components

All component types have certain fields that represent the style. All of these fields may be skipped, in which case the parent's style will be inherited.

bold

Boolean - if true, the component is emboldened.

italic

Boolean - if true, the component is italicized.

underlined

Boolean - if true, the component is underlined.

strikethrough

Boolean - if true, the component is struck out.

obfuscated

Boolean - if true, the component randomly switches between characters of the same width.

color

String - contains the color for the component. Should be one of the normal colors, but can also be a format code (however, the fields relating to styles should be used instead for that purpose). If not present (or set to reset), then the default color for the text will be used, which varies by the situation (in some cases, it is white; in others, it is black; in still others, it is a shade of gray that isn't normally used on text).

insertion

String - contains text to insert. Only used for messages in chat. When shift is held, clicking the component inserts the given text into the chat box at the cursor (potentially replacing selected text). Has no effect on other locations at this time.

clickEvent

JSON object - Defines an event that occurs when this component is clicked. Contains an action key and a value key. value is internally handled as a String, although it can be any type of JSON primitive.

open_url

Opens the given URL in the default web browser. Ignored if the player has opted to disable links in chat; may open a GUI prompting the user if the setting for that is enabled. The link's protocol must be set and must be http or https, for security reasons.

open_file

Cannot be used within JSON chat. Opens a link to any protocol, but cannot be used in JSON chat for security reasons. Only exists to internally implement links for screenshots.

run_command

Runs the given command. Not required to be a command - clicking this only causes the client to send the given content as a chat message, so if not prefixed with /, they will say the given text instead. If used in a book GUI, the GUI is closed after clicking.

twitch_user_info

No longer supported; cannot be used within JSON chat. Only usable in 1.8 and below; twitch support was removed in 1.9. Additionally, this is only used internally by the client. On click, opens a twitch user info GUI screen. Value should be the twitch user name.

suggest_command

Only usable for messages in chat. Replaces the content of the chat box with the given text - usually a command, but it is not required to be a command (commands should be prefixed with /).

change_page

Only usable within written books. Changes the page of the book to the given page, starting at 1. For instance, "value":1 switches the book to the first page. If the page is less than one or beyond the number of pages in the book, the event is ignored.

hoverEvent

JSON object - Defines an event that occurs when this component hovered over. Contains an action key and a value key; action is a String and value is a text component. However, since text components can be serialized as primitives as well as arrays and objects, this can directly be a String. A list of actions:

show_text

The text to display. Can either be a string directly ("value":"la") or a full component ("value":{"text":"la","color":"red"}).

show_item

The NBT of the item to display, in the JSON-NBT format (as would be used in /give). Note that this is a String and not a JSON object - it should either be set in a String directly ("value":"{id:35,Damage:5,Count:2,tag:{display:{Name:Testing}}}") or as text of a component ("value":{"text":"{id:35,Damage:5,Count:2,tag:{display:{Name:Testing}}}"}). If the item is invalid, "Invalid Item!" will be drawn in red instead.

show_entity

A JSON-NBT String describing the entity. Contains 3 values: id, the entity's UUID (with dashes); type (optional), which contains the resource location for the entity's type (eg minecraft:zombie); and name, which contains the entity's custom name (if present). Note that this is a String and not a JSON object. It should be set in a String directly ("value":"{id:7e4a61cc-83fa-4441-a299-bf69786e610a,type:minecraft:zombie,name:Zombie}") or as the content of a component. If the entity is invalid, "Invalid Entity!" will be displayed. Note that the client does not need to have the given entity loaded.

show_achievement

No longer supported. Since 1.12, this no longer exists; advancements instead simply use show_text. The ID of an achievement or statistic to display. Example: "value":"achievement.openInventory".

extra

An array of sibling components. If present, cannot be empty.

Beyond that, there are additional properties. Attempt to parse as each of the following in the order they are described:

String component

A String component contains only text. If the JSON contains a text key, then the component is a String component. The only content of this component is its text, with no additional processing.

Translation component

	The following information needs to be added to this page:
	Is using this with an invalid key intended or deprecated? Also, what exactly happens on invalid formats?

Translates text into the current language. If the JSON contains a translate key, then the component is a translation component.

Translation supports %s and %% format tokens. %% is just an escaped percent symbol. %s marks text to replace using content from the optional with tag. with is an array of components.

As a special case, if the translation key is chat.type.text, it will be changed to chat.type.text.narrate when passed to narrator (although it will remain as chat.type.text in chat).

Keybind component

Displays the client's current keybind for the specified key. If the component contains a keybind key, then it is a keybind component. The value is named after the keys in options.txt (for instance, for key_key.forward in options.txt, key.forward would be used in the component and W would be displayed). For keys that are not known, the value provided should be displayed instead (for instance key.invalid would remain as key.invalid).

Score component

Displays a score. If the JSON contains a score key, then the component is a score component.

The score JSON object contains data about the objective.

When being sent to the client, it must contain name, objective, and value keys. name is a player username or entity UUID (if it is a player, it is a username); objective is the name of the objective; value is the resolved value of that objective.

When being sent to the server, value is not used. name can be an entity selector (that selects one entity), or alternatively * which matches the sending player.

Selector component

Displays the results of an entity selector. Should not be sent to clients; only intended for commands and client-to-server actions. If the component contains a selector key, then it is a selector component.

The server resolves the list selector into a list of entities, each with an appropriate hover event, and joined with commas and "and" (but it lacks a serial comma.

Examples

Here are some examples from the Notchain server for how chat formatting can be used.

TODO - additional examples

Standard chat message

The normal chat message uses a translation component along with some styling.

{"translate":"chat.type.text","with":[{"text":"Herobrine","clickEvent":{"action":"suggest_command","value":"/msg Herobrine "},"hoverEvent":{"action":"show_entity","value":"{id:f84c6a79-0a4e-45e0-879b-cd49ebd4c4e2,name:Herobrine}"},"insertion":"Herobrine"},{"text":"I don't exist"}]}

The chat.type.text translation key becomes <%s> %s, which is then filled in with the player's name and the actual message. Note that the player's name has a click event (which inserts text to message the player), a hover event (which shows the entity ID; also note that type is missing), and an insertion (for the player's name).

Old system

Control Sequences

The client treats certain two-character sequences specially. The first character must be:

• § (U+00A7) for minecraft
• & for minecraft classic

The following character indicates a certain color or formatting to apply to the proceeding text.

The Notchian classic client expects that an escape code in a chat message will be followed by at least one character, and will otherwise crash with a StringIndexOutOfBoundsException. The workaround for servers is to never end a message with a color control character. This is not an issue for the modern Notchian client.

Colors

These correspond very roughly to the colors available in ANSI terminals.

e.g.: This is white, but §4this is dark red

Hex digit to color mapping

1. REDIRECT Text formatting/ColorSample

Sample	Code	Common Name	Name	Foreground Color				Background Color
				R	G	B	Hex	R	G	B	Hex
0	Black	black	0	0	0	#000000	0	0	0	#000000
	1	Dark blue	dark_blue	0	0	170	#0000aa	0	0	42	#00002a
	2	Dark green	dark_green	0	170	0	#00aa00	0	42	0	#002a00
	3	Dark cyan	dark_aqua	0	170	170	#00aaaa	0	42	42	#002a2a
	4	Dark red	dark_red	170	0	0	#aa0000	42	0	0	#2a0000
	5	Purple	dark_purple	170	0	170	#aa00aa	42	0	42	#2a002a
	6	Gold	gold	255	170	0	#ffaa00	42	42	0	#2a2a00
	7	Gray	gray	170	170	170	#aaaaaa	42	42	42	#2a2a2a
	8	Dark gray	dark_gray	85	85	85	#555555	21	21	21	#151515
	9	Blue	blue	85	85	255	#5555ff	21	21	63	#15153f
	a	Bright green	green	85	255	85	#55ff55	21	63	21	#153f15
	b	Cyan	aqua	85	255	255	#55ffff	21	63	63	#153f3f
	c	Red	red	255	85	85	#ff5555	63	21	21	#3f1515
	d	Pink	light_purple	255	85	255	#ff55ff	63	21	63	#3f153f
	e	Yellow	yellow	255	255	85	#ffff55	63	63	21	#3f3f15
	f	White	white	255	255	255	#ffffff	63	63	63	#3f3f3f

Styles

Like the color codes above, style escape codes are created by combining § (U+00A7) with one of the following characters. Style codes can be combined (except for "r") to enable multiple effects at once. Using any color codes will reset the current style back to plain (unknown if this is a bug or intended behavior). The "r" plain style code will also reset the current chat color back to white (may also be a bug). The "k" random style code is used for the "§kFUNKY LOL" message in /title/splashes.txt inside minecraft.jar.

Sample	Code	Style	Name
	k	Random	obfuscated
	l	Bold	bold
	m	Strikethrough	strikethrough
	n	Underlined	underline
	o	Italic	italic
	r	Plain White	reset

Processing chat

Actually handling chat between the client and server is slightly more complicated than simply forwarding chat messages to other players. There's a somewhat complicated interaction regarding the chat settings of each player and whether it is a command or not, which is used to handle the various options in chat settings (specifically, Chat: Shown/Commands Only/Hidden, and the equivalent for narrator).

This is made more complicated by the two different enums, one which represents client settings and the other which represents chat positions.

The client setting (as used in the Client Settings packet) is what the player chose to have displayed, and affects what types of chat messages the server should send:

ID	Name	Meaning
0	Full	The client is willing to accept all chat messages.
1	System	The client is willing to accept messages from commands, but does not want general chat from other players.
2	None	The client does not want any chat at all. (However, it is still fine with above-hotbar game notices)

The message type (as used in the Chat Message packet) indicates the type of chat message:

ID	Name	Meaning
0	Chat	A player-initiated chat message. Note that the Notchian server does not include message-related commands here (/me and /tell); those go in System.
1	System	Feedback from running a command, such as "Your game mode has been updated to creative."
2	Game info	Game state information that is displayed above the hot bar, such as "You may not rest now, the bed is too far away".

Note that it is the server's responsibility to not send packets if the client has the given type disabled. However, it is the client's responsibility to not send incorrect chat packets.

Here's a matrix comparing what packets the server should send to the client by settings:

	Message type
Client setting		Chat	System	Game info
	Full	✔	✔	✔
	System	✘	✔	✔
	Hidden	✘	✘	✔

Here's a matrix comparing what the client may send based off of its chat setting:

	Inbound message
Client setting		Chat message	Command starting with /
	Full	✔	✔
	System	✘	✔
	Hidden	✘	✘

If the client attempts to send a chat message and the server rejects it, the Notchian server will send that client a red chat.cannotSend translation component (which becomes "Cannot send chat message"). Else, if it starts with a /, then the message is processed as a command. Otherwise, it will broadcast a translate component with chat.type.text (which becomes <%s> %s), with the player's name (and the appropriate hover events) as the first format parameter and the message as the second parameter.

Font

Minecraft has two fonts types that can be encountered normally: Ascii (ascii.png) and Unicode (unicode_page_XX.png). The ascii font will fall back upon unicode characters if they are not provided (see below). However, use of the Unicode font can be forced for all characters in the language menu.

There is no glyph for the space character. However, the space character has a width of 4.

Additionally, Minecraft has a Standard Galactic Alphabet font (ascii_sga.png). This cannot be used in chat, but works much the same as the normal Ascii font in terms of width. The SGA font only supports lowercase and uppercase letters (the rest of the glyphs are blank), and has the same indexing as the normal ascii font.

The Minecraft client calculates the widths of the default font when the texture is loaded, whilst the sizes of the unicode type are provided in glyph_sizes.bin. Each byte in glyph_sizes.bin contains the start and end position of each character, the top nibble (0xF0) is the start position and the bottom nibble (0x0F) is the end position (relative to the character's position in the font sheet). Example: https://gist.github.com/TkTech/dff9bbe54c9a074612e1

The Ascii font supports these characters, with the given indexes in ascii.png:

Codepoint	Char	index	x	y	width
\u00c0	À	0	0	0	6
\u00c1	Á	1	1	0	6
\u00c2	Â	2	2	0	6
\u00c8	È	3	3	0	6
\u00ca	Ê	4	4	0	6
\u00cb	Ë	5	5	0	6
\u00cd	Í	6	6	0	4
\u00d3	Ó	7	7	0	6
\u00d4	Ô	8	8	0	6
\u00d5	Õ	9	9	0	6
\u00da	Ú	10	10	0	6
\u00df	ß	11	11	0	6
\u00e3	ã	12	12	0	6
\u00f5	õ	13	13	0	6
\u011f	ğ	14	14	0	6
\u0130	İ	15	15	0	4
\u0131	ı	16	0	1	4
\u0152	Œ	17	1	1	6
\u0153	œ	18	2	1	7
\u015e	Ş	19	3	1	6
\u015f	ş	20	4	1	6
\u0174	Ŵ	21	5	1	6
\u0175	ŵ	22	6	1	6
\u017e	ž	23	7	1	6
\u0207	ȇ	24	8	1	6
\u0000		25	9	1	-
\u0000		26	10	1	-
\u0000		27	11	1	-
\u0000		28	12	1	-
\u0000		29	13	1	-
\u0000		30	14	1	-
\u0000		31	15	1	-
\u0020		32	0	2	4
\u0021	!	33	1	2	2
\u0022	"	34	2	2	5
\u0023	#	35	3	2	6
\u0024	$	36	4	2	6
\u0025	%	37	5	2	6
\u0026	&	38	6	2	6
\u0027	'	39	7	2	3
\u0028	(	40	8	2	5
\u0029	)	41	9	2	5
\u002a	*	42	10	2	5
\u002b	+	43	11	2	6
\u002c	,	44	12	2	2
\u002d	-	45	13	2	6
\u002e	.	46	14	2	2
\u002f	/	47	15	2	6
\u0030	0	48	0	3	6
\u0031	1	49	1	3	6
\u0032	2	50	2	3	6
\u0033	3	51	3	3	6
\u0034	4	52	4	3	6
\u0035	5	53	5	3	6
\u0036	6	54	6	3	6
\u0037	7	55	7	3	6
\u0038	8	56	8	3	6
\u0039	9	57	9	3	6
\u003a	:	58	10	3	2
\u003b	;	59	11	3	2
\u003c	<	60	12	3	5
\u003d	=	61	13	3	6
\u003e	>	62	14	3	5
\u003f	?	63	15	3	6
\u0040	@	64	0	4	7
\u0041	A	65	1	4	6
\u0042	B	66	2	4	6
\u0043	C	67	3	4	6
\u0044	D	68	4	4	6
\u0045	E	69	5	4	6
\u0046	F	70	6	4	6
\u0047	G	71	7	4	6
\u0048	H	72	8	4	6
\u0049	I	73	9	4	4
\u004a	J	74	10	4	6
\u004b	K	75	11	4	6
\u004c	L	76	12	4	6
\u004d	M	77	13	4	6
\u004e	N	78	14	4	6
\u004f	O	79	15	4	6
\u0050	P	80	0	5	6
\u0051	Q	81	1	5	6
\u0052	R	82	2	5	6
\u0053	S	83	3	5	6
\u0054	T	84	4	5	6
\u0055	U	85	5	5	6
\u0056	V	86	6	5	6
\u0057	W	87	7	5	6
\u0058	X	88	8	5	6
\u0059	Y	89	9	5	6
\u005a	Z	90	10	5	6
\u005b	[	91	11	5	4
\u005c	\	92	12	5	6
\u005d	]	93	13	5	4
\u005e	^	94	14	5	6
\u005f	_	95	15	5	6
\u0060	`	96	0	6	3
\u0061	a	97	1	6	6
\u0062	b	98	2	6	6
\u0063	c	99	3	6	6
\u0064	d	100	4	6	6
\u0065	e	101	5	6	6
\u0066	f	102	6	6	5
\u0067	g	103	7	6	6
\u0068	h	104	8	6	6
\u0069	i	105	9	6	2
\u006a	j	106	10	6	6
\u006b	k	107	11	6	5
\u006c	l	108	12	6	3
\u006d	m	109	13	6	6
\u006e	n	110	14	6	6
\u006f	o	111	15	6	6
\u0070	p	112	0	7	6
\u0071	q	113	1	7	6
\u0072	r	114	2	7	6
\u0073	s	115	3	7	6
\u0074	t	116	4	7	4
\u0075	u	117	5	7	6
\u0076	v	118	6	7	6
\u0077	w	119	7	7	6
\u0078	x	120	8	7	6
\u0079	y	121	9	7	6
\u007a	z	122	10	7	6
\u007b	{	123	11	7	5
\u007c		124	12	7	2
\u007d	}	125	13	7	5
\u007e	~	126	14	7	7
\u0000		127	15	7	-
\u00c7	Ç	128	0	8	6
\u00fc	ü	129	1	8	6
\u00e9	é	130	2	8	6
\u00e2	â	131	3	8	6
\u00e4	ä	132	4	8	6
\u00e0	à	133	5	8	6
\u00e5	å	134	6	8	6
\u00e7	ç	135	7	8	6
\u00ea	ê	136	8	8	6
\u00eb	ë	137	9	8	6
\u00e8	è	138	10	8	6
\u00ef	ï	139	11	8	4
\u00ee	î	140	12	8	6
\u00ec	ì	141	13	8	3
\u00c4	Ä	142	14	8	6
\u00c5	Å	143	15	8	6
\u00c9	É	144	0	9	6
\u00e6	æ	145	1	9	6
\u00c6	Æ	146	2	9	6
\u00f4	ô	147	3	9	6
\u00f6	ö	148	4	9	6
\u00f2	ò	149	5	9	6
\u00fb	û	150	6	9	6
\u00f9	ù	151	7	9	6
\u00ff	ÿ	152	8	9	6
\u00d6	Ö	153	9	9	6
\u00dc	Ü	154	10	9	6
\u00f8	ø	155	11	9	6
\u00a3	£	156	12	9	6
\u00d8	Ø	157	13	9	6
\u00d7	×	158	14	9	4
\u0192	ƒ	159	15	9	6
\u00e1	á	160	0	10	6
\u00ed	í	161	1	10	3
\u00f3	ó	162	2	10	6
\u00fa	ú	163	3	10	6
\u00f1	ñ	164	4	10	6
\u00d1	Ñ	165	5	10	6
\u00aa	ª	166	6	10	6
\u00ba	º	167	7	10	6
\u00bf	¿	168	8	10	6
\u00ae	®	169	9	10	7
\u00ac	¬	170	10	10	6
\u00bd	½	171	11	10	6
\u00bc	¼	172	12	10	6
\u00a1	¡	173	13	10	2
\u00ab	«	174	14	10	6
\u00bb	»	175	15	10	6
\u2591	░	176	0	11	8
\u2592	▒	177	1	11	9
\u2593	▓	178	2	11	9
\u2502	│	179	3	11	6
\u2524	┤	180	4	11	6
\u2561	╡	181	5	11	6
\u2562	╢	182	6	11	8
\u2556	╖	183	7	11	8
\u2555	╕	184	8	11	6
\u2563	╣	185	9	11	8
\u2551	║	186	10	11	8
\u2557	╗	187	11	11	8
\u255d	╝	188	12	11	8
\u255c	╜	189	13	11	8
\u255b	╛	190	14	11	6
\u2510	┐	191	15	11	6
\u2514	└	192	0	12	9
\u2534	┴	193	1	12	9
\u252c	┬	194	2	12	9
\u251c	├	195	3	12	9
\u2500	─	196	4	12	9
\u253c	┼	197	5	12	9
\u255e	╞	198	6	12	9
\u255f	╟	199	7	12	9
\u255a	╚	200	8	12	9
\u2554	╔	201	9	12	9
\u2569	╩	202	10	12	9
\u2566	╦	203	11	12	9
\u2560	╠	204	12	12	9
\u2550	═	205	13	12	9
\u256c	╬	206	14	12	9
\u2567	╧	207	15	12	9
\u2568	╨	208	0	13	9
\u2564	╤	209	1	13	9
\u2565	╥	210	2	13	9
\u2559	╙	211	3	13	9
\u2558	╘	212	4	13	9
\u2552	╒	213	5	13	9
\u2553	╓	214	6	13	9
\u256b	╫	215	7	13	9
\u256a	╪	216	8	13	9
\u2518	┘	217	9	13	6
\u250c	┌	218	10	13	9
\u2588	█	219	11	13	9
\u2584	▄	220	12	13	9
\u258c	▌	221	13	13	5
\u2590	▐	222	14	13	9
\u2580	▀	223	15	13	9
\u03b1	α	224	0	14	8
\u03b2	β	225	1	14	7
\u0393	Γ	226	2	14	7
\u03c0	π	227	3	14	8
\u03a3	Σ	228	4	14	7
\u03c3	σ	229	5	14	8
\u03bc	μ	230	6	14	8
\u03c4	τ	231	7	14	8
\u03a6	Φ	232	8	14	7
\u0398	Θ	233	9	14	8
\u03a9	Ω	234	10	14	8
\u03b4	δ	235	11	14	7
\u221e	∞	236	12	14	9
\u2205	∅	237	13	14	9
\u2208	∈	238	14	14	6
\u2229	∩	239	15	14	7
\u2261	≡	240	0	15	7
\u00b1	±	241	1	15	7
\u2265	≥	242	2	15	7
\u2264	≤	243	3	15	7
\u2320	⌠	244	4	15	9
\u2321	⌡	245	5	15	6
\u00f7	÷	246	6	15	7
\u2248	≈	247	7	15	8
\u00b0	°	248	8	15	7
\u2219	∙	249	9	15	6
\u00b7	·	250	10	15	6
\u221a	√	251	11	15	9
\u207f	ⁿ	252	12	15	7
\u00b2	²	253	13	15	6
\u25a0	■	254	14	15	7
\u0000		255	15	15	-

	The following information needs to be added to this page:
	Clearer documentation on how rendering works (for instance, shadows)