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This page describes how to send messages on the client side from an
add-on running in the
side-panel iframe to an
add-on running in the main
stage iframe. Frame-to-frame
messaging only occurs on the client side, so message delivery is near
instantaneous.
To send a message:
From the side panel to the main stage, use the
notifyMainStage()
method.
The payload
length must conform to its specified size limit.
To receive the message, the add-on must subscribe to
the
frameToFrameMessage
callback. The following code sample shows how to subscribe to a
frameToFrameMessage callback:
Frame-to-frame messages sent by a given participant are only visible by
that same participant. To send messages or state to other participants,
learn how to share add-on
state.
Message delivery is only attempted once. To receive messages, the receiving
panel must be open and the app must subscribe to the callback before the
message is sent.
[[["Easy to understand","easyToUnderstand","thumb-up"],["Solved my problem","solvedMyProblem","thumb-up"],["Other","otherUp","thumb-up"]],[["Missing the information I need","missingTheInformationINeed","thumb-down"],["Too complicated / too many steps","tooComplicatedTooManySteps","thumb-down"],["Out of date","outOfDate","thumb-down"],["Samples / code issue","samplesCodeIssue","thumb-down"],["Other","otherDown","thumb-down"]],["Last updated 2025-01-30 UTC."],[[["This page explains how Google Meet add-ons can send messages between the side panel and main stage iframes using client-side frame-to-frame messaging."],["Add-ons use `notifyMainStage()` and `notifySidePanel()` methods to send messages and subscribe to the `frameToFrameMessage` callback to receive them."],["Frame-to-frame messages are only visible to the sender and require the receiving panel to be open and subscribed to the callback for delivery."],["For sharing state with other participants, refer to the guide on add-on state collaboration."]]],["Add-ons in different iframes (side panel and main stage) can exchange messages client-side. The side panel sends messages to the main stage using `notifyMainStage()`, while the main stage uses `notifySidePanel()` to send messages to the side panel. To receive messages, add-ons must subscribe to the `frameToFrameMessage` callback. Messages are participant-specific and delivered once; the receiving panel must be open and subscribed. Payload size limitations apply. The Animation sample add-on demonstrates this functionality.\n"]]
