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Introducing Sign In With Solana (SIWS)

Brian Friel
Sign In With Solana (SIWS) image on the Phantom blog

    Today, we’re excited to launch a new feature that lets apps securely authenticate their users with just a Solana address.

    The current state of authentication is broken

    If you connect your wallet to any major app today, chances are you’ll be met with a popup that looks something like this:

    Sign message popup image on the Phantom blog
    Sign message popup

    These kinds of signature requests can be jarring—they often pop up unexpectedly right after you connect your wallet. To make matters worse, it isn’t always clear what they’re asking you to sign. For new users, these requests can be scary. For returning users, they’re trained to sign messages that they don’t fully understand.

    Why are these sign message requests even needed? The reason is authentication. When you connect your wallet to an app today, most wallets simply share your address without verifying that you control the corresponding private key. For consumer-grade applications like Magic Eden, Tensor, and Drip though, this isn’t enough. In order for these apps to build personalized features like user profiles, private messaging, and loyalty programs, they need to verify that their users are who they say they are.

    By asking you to sign a message, apps can prove that you control the private key for the address you’re connecting with. But there’s a problem: there’s no standard way to go about asking for these signatures. Each app has to come up with its own authentication flow, which can result in opaque signature requests. This fragmentation, along with the added friction of triggering a second popup, results in a poor user experience.

    Traditional message signing flow in Phantom Wallet
    Traditional message signing flow in Phantom Wallet

    Enter Sign In With Solana

    Today, we’re launching a new feature that lets apps authenticate their users with just a Solana address. Sign In With Solana (SIWS) is a fast, easy, and secure solution to the problem of authenticating users with self-custody wallets. As part of our launch, we’re unveiling:

    • A new one-click signIn method
    • Support for the Wallet Standard’s SIWS feature
    Introducing Sign In With Solana (SIWS)

    One-click sign-in

    As of Phantom 23.11, Solana developers can make use of the new signIn method on all extension platforms, with mobile support coming soon. This new method prompts users to connect and sign a standardized authentication message in a single click, greatly improving the experience for both users and developers.

    Sign In With Solana (SIWS) tutorial featuring DRiP

    For developers, this new signIn method can be viewed as a drop-in replacement for the two-step connect and signMessage authentication flow. If a user is already connected to their app, developers can also use signIn as a more streamlined alternative to signMessage.

    signIn shifts the responsibility of message construction from apps to the wallet, providing developers with a consistent API for creating standardized authentication messages. If specified, Phantom can scrutinize message data such as a site’s domain or the time at which the message was issuedAt to ensure its legitimacy or raise red flags for suspicious activity.

    Sign-in request error message image on the Phantom blog

    Support for the Solana Wallet Standard

    As part of our launch, we worked with Solana Labs to create an open standard for the Solana ecosystem. We’re proud to announce that our signIn method comes with full support for the Solana Wallet Standard’s SIWS feature. Inspired by EIP-4361, this feature is custom-tailored to Solana and can be integrated by other wallets in the ecosystem.

    As a first-class feature of the Wallet Standard, SIWS also comes with full support in the Solana Wallet Adapter. Developers who rely on the Wallet Adapter can integrate signIn natively, without worrying about losing wallet compatibility.

    Integrate Sign In With Solana Today

    Sign In With Solana is now ready for integration. To get started, check out our developer integration guide and demo app. For questions and feedback, please reach out to us on our developer forums.

    Many thanks to Jordan Sexton for his review and feedback!