Are there any user account platforms that support single sign-on and linked roaming access across charging networks?

Yes. In EV charging, the concept you’re describing is usually called roaming, and many platforms support both:

• Single sign-on / one account
• Cross-network access to chargers operated by multiple charging networks

Common examples include:

• Hubject — one of the best-known roaming platforms, connecting many CPOs and eMSPs across regions.
• Gireve — widely used in Europe for interoperability and roaming.
• e-clearing.net — another roaming/interoperability platform for charge point operators and mobility providers.
• OCPI-based platforms — many networks use the Open Charge Point Interface (OCPI) standard to enable cross-network authentication, pricing, and session management.

In practice, this usually works like:

• You create an account with one eMSP/app/provider
• That provider has roaming agreements with multiple charging networks
• You can then authenticate at partner chargers using:
  • an app,
  • RFID card,
  • or sometimes plug-and-charge, depending on support

If you want, I can also give you:

1. a list of consumer-facing apps/services that provide roaming access, or
2. a technical comparison of the main roaming platforms and standards.