Customer.io Web Device Mode: SDK Version 2
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3 minute read
- Date: Sep 28, 2026
Customer.io web device mode now supports the Customer.io Data Pipelines JavaScript client through the Web SDK Version setting. Select v2 to send browser events through a Data Pipelines source and optionally deliver in-app messages to unidentified visitors.
Existing destinations continue to use v1, and new destinations currently default to v1. You choose when to migrate each web device mode connection.
Why this exists
The previous integration loaded only Customer.io’s legacy Journeys snippet. Anonymous in-app messages require the newer Data Pipelines JavaScript client, which uses a Data Pipelines write key and a different event-delivery path. The version selector lets you adopt that client without changing existing connections automatically.
Key features
- Per-source SDK selection: Choose v1 or v2 for each web source connected in device mode.
- Data Pipelines delivery: v2 loads the Customer.io Data Pipelines JavaScript client and authenticates it with the Data Pipelines source’s write key.
- Consistent anonymous identity: The v2 integration applies the RudderStack anonymous ID to the Customer.io client before sending events.
- Anonymous in-app messages: Load the Customer.io In-App Plugin for unidentified visitors when your Customer.io workspace and plan support the feature.
- Safe opt-in: Existing destinations remain on v1, so no connection changes until you select v2.
Get started
- Open your Customer.io destination in the RudderStack dashboard.
- Connect a JavaScript source and select Device mode.
- Set Web SDK Version to v2.
- In the connection settings, enter the Data Pipelines Write Key for your Customer.io Data Pipelines JavaScript source.
- Save the destination settings.
See the Customer.io Setup Guide for credential requirements, content security policy domains, and in-app message prerequisites.
How to migrate
Before switching an existing connection, create a Data Pipelines JavaScript source in Customer.io and connect it to your Journeys workspace. Then add its write key and select v2 in RudderStack. If you skip the Journeys connection, web events enter Data Pipelines but don’t reach Journeys.
Follow Migrate to v2 for the complete migration procedure. Keep the Site ID and API key when the destination also serves cloud mode or mobile device mode sources. Cloud and mobile delivery are unchanged by the web setting.
Impact on existing connections
| Connection | Behavior |
|---|---|
| Existing web device mode destinations | Stay on v1 until you explicitly select v2 |
| New web device mode destinations | Currently default to v1; select v2 to use Data Pipelines |
| Cloud mode and mobile device mode connections | Remain unchanged by the Web SDK Version setting |
Resources
- Customer.io Setup Guide — credentials, SDK settings, and anonymous in-app message prerequisites
- Customer.io Device Mode Integration — SDK behavior, event handling, and migration steps
- Data Pipelines write key — where to find the v2 browser credential
