Server-sent events

Method of continuously sending data from a server to the browser, rather than repeatedly requesting it (EventSource interface, used to fall under HTML5)

Spec	https://html.spec.whatwg.org/multipage/comms.html#server-sent-events
Status	WHATWG Living Standard

IE	Edge	Firefox	Chrome	Safari	Opera
			108
		107	107	TP
		106	106	16.1
11	105	105	105	16.0	91
10	104	104	104	15.6	90
9	103	103	103	15.5	89
8	102	102	102	15.4	88
Show all
7	101	101	101	15.2-15.3	87
6	100	100	100	15.1	86
5.5	99	99	99	15	85
	98	98	98	14.1	84
	97	97	97	14	83
	96	96	96	13.1	82
	95	95	95	13	81
	94	94	94	12.1	80
	93	93	93	12	79
	92	92	92	11.1	78
	91	91	91	11	77
	90	90	90	10.1	76
	89	89	89	10	75
	88	88	88	9.1	74
	87	87	87	9	73
	86	86	86	8	72
	85	85	85	7.1	71
	84	84	84	7	70
	83	83	83	6.1	69
	81	82	81	6	68
	80	81	80	5.1	67
	79	80	79	5	66
	18	79	78	4	65
	17	78	77	3.2	64
	16	77	76	3.1	63
	15	76	75		62
	14	75	74		60
	13	74	73		58
	12	73	72		57
		72	71		56
		71	70		55
		70	69		54
		69	68		53
		68	67		52
		67	66		51
		66	65		50
		65	64		49
		64	63		48
		63	62		47
		62	61		46
		61	60		45
		60	59		44
		59	58		43
		58	57		42
		57	56		41
		56	55		40
		55	54		39
		54	53		38
		53	52		37
		52	51		36
		51	50		35
		50	49		34
		49	48		33
		48	47		32
		47	46		31
		46	45		30
		45	44		29
		44	43		28
		43	42		27
		42	41		26
		41	40		25
		40	39		24
		39	38		23
		38	37		22
		37	36		21
		36	35		20
		35	34		19
		34	33		18
		33	32		17
		32	31		16
		31	30		15
		30	29		12.1
		29	28		12
		28	27		11.6
		27	26		11.5
		26	25		11.1
		25	24		11
		24	23		10.6
		23	22		10.5
		22	21		10.0-10.1
		21	20		9.5-9.6
		20	19		9
		19	18
		18	17
		17	16
		16	15
		15	14
		14	13
		13	12
		12	11
		11	10
		10	9
		9	8
		8	7
		7	6
		6	5
		5	4
		4
		3.6
		3.5
		3
		2

Safari on iOS	Opera Mini	Android Browser	Blackberry Browser	Opera Mobile	Android Chrome	Android Firefox	IE Mobile	Android UC Browser	Samsung Internet	QQ Browser	Baidu Browser	KaiOS Browser
16.1
16.0	all	105	10	64	105	104	11	13.4	18.0	13.1	13.18	2.5
15.6		4.4.3-4.4.4	7	12.1			10		17.0
15.5		4.4		12					16.0
15.4		4.2-4.3		11.5					15.0
Show all
15.2-15.3		4.1		11.1					14.0
15.0-15.1		4		11					13.0
14.5-14.8		3		10					12.0
14.0-14.4		2.3							11.1-11.2
13.4-13.7		2.2							10.1
13.3		2.1							9.2
13.2									8.2
13.0-13.1									7.2-7.4
12.2-12.5									6.2-6.4
12.0-12.1									5.0-5.4
11.3-11.4									4
11.0-11.2
10.3
10.0-10.2
9.3
9.0-9.2
8.1-8.4
8
7.0-7.1
6.0-6.1
5.0-5.1
4.2-4.3
4.0-4.1
3.2

Notes

Bugs

• Reportedly, CORS in EventSource is currently supported in Firefox 10+, Opera 12+, Chrome 26+, Safari 7.0+.

• In Firefox prior to version 36 server-sent events do not reconnect automatically in case of a connection interrupt (bug)

• Firefox currently does not support EventSource in service workers

• Firefox 52 and below do not support EventSource in web/shared workers

• Antivirus software may block the event streaming data chunks.

Resources

• HTML5 Rocks tutorial
• has.js test
• Polyfill