Set custom User IDs

To enable seamless, personalized communication across all platforms and devices, it is essential to assign a custom User ID to each user.

User ID is a unique identifier that is assigned to each user to maintain consistent user data across all their devices. This allows you to provide your audience with a seamless user experience across their devices.

For a detailed explanation of how User IDs work and how they relate to devices, see this guide.

By default, when your app is first launched, Pushwoosh creates a User ID equal to the device’s Hardware ID (HWID). This means each device is treated as a separate user. So if one person uses more than one device, like a phone and a tablet, Pushwoosh sees them as two separate users, and their data won’t be connected.

Setting a custom User ID lets you link all devices and contact methods under one profile. This provides several important benefits:

Pushwoosh charges based on the number of unique users in your database.

Learn more about Pushwoosh pricing

If you don’t set a custom User ID, each device counts as a separate user, even if they belong to the same person. For example, if one user uses both a mobile phone and a tablet, they may be counted as two users.

For a unified experience across push notifications, email, SMS, in-app, WhatsApp, and other channels, all user data must be linked under a single User ID.

By setting a custom User ID, you ensure that Pushwoosh recognizes all contact methods (devices, emails, phone numbers) as belonging to the same user, which is essential for consistent and personalized omnichannel campaigns.

Learn more about Omnichannel campaigns

A custom User ID allows Pushwoosh to maintain a complete, unified profile for each user. This profile includes:

• All devices and contact info linked to the same user
• Tags
• Event history and campaign participation
• Messages sent and opened

You can view and manage this data in User Explorer, helping you deliver more accurate targeting and better personalization.