Refoss Open API Wi-Fi Dual Channel Relay Switch, R21 (R21): Refoss R21, the main image of Refoss's own store listing "Refoss Open API Wi-Fi Dual Channel Relay Switch, R21", which sells this one model (SKU R21-EU). The dual-channel relay module beside a phone showing the Refoss app; Refoss shows no plain product photo of it.

1 photo · Image from refoss.net

Photo sources

Manufacturer and seller images. Configuration examples may include additional equipment.

Image source: Refoss R21, the main image of Refoss's own store listing "Refoss Open API Wi-Fi Dual Channel Relay Switch, R21", which sells this one model (SKU R21-EU). The dual-channel relay module beside a phone showing the Refoss app; Refoss shows no plain product photo of it.

Refoss Open API Wi-Fi Dual Channel Relay Switch, R21 (R21)

Name: Refoss Open API Wi-Fi Dual Channel Relay Switch, R21 (R21)
Brand: Refoss
SKU: R21

By RefossSKU R21

Energy monitors

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Device typeIn-wall switch Max switched load (A)Not statedMax switched load (W)Not statedMeasurement channelsDual Channel Control: Manage two devices independently with a single unit, perfect for controlling multiple home appliances or lighting circuits.Current sensorsNot stated Current ratingNot stated

Key specs

Units

SKU: R21
Official product page
Sources
Printed as "Refoss Open API Wi-Fi Dual Channel Relay Switch, R21".
Official product page: Refoss product page: Refoss Open API Wi-Fi Dual Channel Relay Switch, R21 (captured October 12, 2026) Checked Oct 12, 2026 · Earlier document
Location: product title
Documented
Device type: In-wall switch
Official product page
Sources
Printed as "Refoss Open API Wi-Fi Dual Channel Relay Switch, R21"; "Energy Monitor: Track energy consumption for connected devices in real-time, providing valuable insights into power usage and enabling smarter energy management".
Official product page: Refoss product page: Refoss Open API Wi-Fi Dual Channel Relay Switch, R21 (captured October 12, 2026) Checked Oct 12, 2026 · Earlier document
Location: product title ("Relay Switch"; behind-the-wall placement not stated in words on the R21 page)
Documented
Communications: Fully Open API Access: Supports JSON-RPC 2.0 via HTTP, webhook, and MQTT for advanced custom integrations.
Official product page
Sources
Printed as "Fully Open API Access: Supports JSON-RPC 2.0 via HTTP, webhook, and MQTT for advanced custom integrations.".
Official product page: Refoss product page: Refoss Open API Wi-Fi Dual Channel Relay Switch, R21 (captured October 12, 2026) Checked Oct 12, 2026 · Earlier document
Location: Product page and documents as quoted
Documented
Measurement channels: Dual Channel Control: Manage two devices independently with a single unit, perfect for controlling multiple home appliances or lighting circuits.
Official product page
Sources
Printed as "Dual Channel Control: Manage two devices independently with a single unit, perfect for controlling multiple home appliances or lighting circuits.".
Official product page: Refoss product page: Refoss Open API Wi-Fi Dual Channel Relay Switch, R21 (captured October 12, 2026) Checked Oct 12, 2026 · Earlier document
Location: Product page and documents as quoted
Documented

All specs3

Device type: In-wall switch
Official product page
Sources
Printed as "Refoss Open API Wi-Fi Dual Channel Relay Switch, R21"; "Energy Monitor: Track energy consumption for connected devices in real-time, providing valuable insights into power usage and enabling smarter energy management".
Official product page: Refoss product page: Refoss Open API Wi-Fi Dual Channel Relay Switch, R21 (captured October 12, 2026) Checked Oct 12, 2026 · Earlier document
Location: product title ("Relay Switch"; behind-the-wall placement not stated in words on the R21 page)
Documented
Communications: Fully Open API Access: Supports JSON-RPC 2.0 via HTTP, webhook, and MQTT for advanced custom integrations.
Official product page
Sources
Printed as "Fully Open API Access: Supports JSON-RPC 2.0 via HTTP, webhook, and MQTT for advanced custom integrations.".
Official product page: Refoss product page: Refoss Open API Wi-Fi Dual Channel Relay Switch, R21 (captured October 12, 2026) Checked Oct 12, 2026 · Earlier document
Location: Product page and documents as quoted
Documented
Measurement channels: Dual Channel Control: Manage two devices independently with a single unit, perfect for controlling multiple home appliances or lighting circuits.
Official product page
Sources
Printed as "Dual Channel Control: Manage two devices independently with a single unit, perfect for controlling multiple home appliances or lighting circuits.".
Official product page: Refoss product page: Refoss Open API Wi-Fi Dual Channel Relay Switch, R21 (captured October 12, 2026) Checked Oct 12, 2026 · Earlier document
Location: Product page and documents as quoted
Documented

Published claims and calculations, not independent test results.

Documents

1 on file

WEB
Refoss product page: Refoss Open API Wi-Fi Dual Channel Relay Switch, R21 (captured October 12, 2026)OfficialRefossOfficial product page
Source details
Revision
Not stated
Revision date
Not stated
Archived copy captured on 2026-10-12.
Location: Product page
Retrieved Oct 12, 2026
Refoss's own product page, captured October 12, 2026 with the paced research fetcher. Manufacturer statements, not independent tests.
Open