Protocol Reference

Property	Value
Transport	TCP
Port	`55443`
Encoding	UTF-8 plain text, no encryption
Message delimiter	`\r\n`
Discovery	SSDP over UDP multicast
Rate limit	~10 commands/sec (TCP mode)

LAN control must be explicitly enabled in the Yeelight mobile app: Device → Settings → LAN Control

Official PDF spec (incomplete): Yeelight Inter-Operation Spec (PDF)

Device Discovery (SSDP)

Devices are discovered via SSDP (UPnP-style multicast).

M-SEARCH request — send as UDP to 239.255.255.250:1982:


M-SEARCH * HTTP/1.1\r\n
HOST: 239.255.255.250:1982\r\n
MAN: "ssdp:discover"\r\n
ST: wifi_bulb\r\n
\r\n

Response — HTTP/1.1 headers:

Header	Example	Description
`Location`	`yeelight://192.168.1.5:55443`	IP and port for TCP connection
`id`	`0x000000000484af7d`	Unique device identifier (hex)
`model`	`lamp15`	Logical model name (not hardware SKU)
`name`	`My Light Bar`	User-assigned name
`power`	`on`	Current power state
`bright`	`100`	Current brightness (1–100)
`ct`	`4000`	Current color temperature (Kelvin)
`rgb`	`16711680`	Current RGB as integer
`support`	`get_prop set_power ...`	Space-separated list of supported methods

The support field is the authoritative source for what commands a device accepts.

Command Format

Request


{ "id": 1, "method": "set_bright", "params": [50, "smooth", 500] }

Response (success)


{ "id": 1, "result": ["ok"] }

Response (error)


{ "id": 3, "error": { "code": -1, "message": "unsupported method" } }

Push notifications (unsolicited)


{ "method": "props", "params": { "power": "on", "bright": "75" } }

Sent by the device whenever state changes from any source (physical button, another app, etc.).

Capability System

Capability detection is based on which methods appear in the support SSDP field. The model field identifies the logical device type — see Devices for the full compatibility matrix.

Group	Methods	Capability
Color	`set_rgb`, `set_hsv`	Main channel supports RGB
Color temp	`set_ct_abx`	Main channel supports CT
Flow	`start_cf`, `stop_cf`	Main channel supports animations
Background	`bg_set_power`, `bg_set_rgb`…	Device has a background channel
Music mode	`set_music`	TCP music mode supported
Segment	`set_segment_rgb`	Per-side control (lamp15-specific)
UDP/Chroma	`udp_sess_new`, `udp_chroma_sess_new`	Razer Chroma integration

Flow Animations


start_cf(count, action, flow_expression)
bg_start_cf(count, action, flow_expression)

Parameter	Values
`count`	`0` = infinite, `N` = repeat N times
`action`	`0` = restore, `1` = stay on last frame, `2` = turn off
frame	`duration_ms, mode, value, brightness` (mode: 1=RGB, 2=CT, 7=sleep)

Example — rainbow loop on background channel:


{
  "method": "bg_start_cf",
  "params": [0, 0, "2000,1,16711680,100,2000,1,65280,100,2000,1,255,100"]
}

Music Mode

Music mode inverts the TCP connection direction: the lamp connects to a server the app opens. This removes the rate limit entirely.


{ "method": "set_music", "params": [1, "192.168.1.100", 54321] }

Gated by set_music in the support field. lamp15 does not support music mode.

In music mode: the lamp does not respond to get_prop — state must be tracked locally.

UDP / Chroma Mode

For high-frequency reactive effects, the device has an undocumented UDP session mode used by Razer Synapse internally.

Method	Description
`udp_sess_new`	Open a UDP session
`udp_sess_keep_alive`	Keepalive
`udp_chroma_sess_new`	Razer Chroma variant

Protocol not publicly documented.

LAN Control Availability

Xiaomi forced Yeelight to remove LAN control from some devices post-sale:

Device	Firmware	Status
bslamp2	2.0.6_0041+	Removed. Toggle disappeared from Yeelight app.

“lan control feature is from yeelight, xiaomi company takes it as a risk, so we have to disable it.” — Yeelight staff, forum.yeelight.com Feb 2021

Always use SSDP discovery as the source of truth — if a device doesn’t respond to M-SEARCH, LAN is either disabled or removed.

For the full command method reference see Commands Reference.