The digital identity landscape is evolving rapidly, and one of the most promising advancements in recent years is Sign-In with Ethereum (SIWE)—a secure, decentralized authentication method now seamlessly integrated into Auth0 via a powerful marketplace partnership with Spruce. This innovation marks a pivotal step toward bridging Web2 and Web3 identity systems, enabling developers to offer users a familiar login experience while leveraging the security and ownership benefits of blockchain technology.
With SIWE, users can authenticate using their Ethereum wallets—such as MetaMask, Coinbase Wallet, or WalletConnect—without relying on traditional usernames and passwords. Instead, they sign a message with their private key, proving ownership of their wallet in a privacy-preserving way. This integration brings decentralized identity into mainstream application development, making it easier than ever to onboard the growing Web3 user base.
👉 Discover how decentralized login can transform your app’s user experience
The Rise of Web3 Identity and Authentication
Web3 isn't just about cryptocurrencies and NFTs—it's about redefining digital ownership and identity. As more users adopt blockchain wallets to manage assets, there's a growing demand for those same wallets to serve as universal login tools across platforms.
According to recent estimates, over 300 million people now own some form of cryptocurrency. Among them, 71 million wallets hold Ethereum, forming the backbone of a vibrant ecosystem where self-sovereign identity is becoming a reality. These users already have the tools: private keys stored in non-custodial wallets like MetaMask, Portis, or Torus, which allow full control without third-party interference.
Even custodial solutions like Coinbase, which serves over 89 million verified users, are adapting by offering wallet functionality that supports both transactions and authentication. Meanwhile, Fortmatic (now Magic) enables email-and-password-like access to private keys—making Web3 logins more approachable for mainstream audiences.
A key enabler of this shift is WalletConnect, an open protocol that allows apps to securely connect with any Web3 wallet. With over 160 integrated applications, WalletConnect has become the go-to bridge between dApps and user wallets—further accelerating adoption.
Additionally, tools like the Ethereum Name Service (ENS) simplify interactions by replacing complex wallet addresses with human-readable names (e.g., alice.eth). With over 300,000 active users, ENS is making blockchain access more intuitive and less error-prone.
This widespread adoption sets the stage for SIWE—a standardized, secure way to use Ethereum wallets as identity providers.
What Is Sign-In with Ethereum (SIWE)?
Sign-In with Ethereum (SIWE) is an open standard (EIP-4361) developed by Spruce in collaboration with the Ethereum Foundation and ENS. It allows users to authenticate to websites and applications using their Ethereum wallet by signing a cryptographic message.
Behind the scenes, SIWE works similarly to OAuth providers like Google or Facebook Login—but instead of trusting a centralized entity, authentication relies on blockchain-verified signatures. When a user logs in, they sign a challenge message with their private key. The server verifies this signature against their public wallet address, confirming identity without exposing sensitive data.
This approach enables:
- Passwordless authentication: No need to remember credentials.
- User sovereignty: Users fully control their identity.
- Phishing resistance: Signatures are domain-specific and non-replayable.
- Interoperability: Works across any app supporting Ethereum-based wallets.
The Auth0 Lab team recognized early on that smart contracts could store verifiable credentials, JWT claims, and other authorization data—enabling richer, more secure identity models. Their December 2021 demo of SIWE integration with Auth0 quickly gained traction within the Web3 community, drawing attention from projects like MetaMask and fueling engagement in the Auth0 Lab Discord.
Today, thanks to Spruce’s official SIWE integration on the Auth0 Marketplace, any developer can enable Ethereum-based login in minutes.
How to Add SIWE to Your Auth0 Tenant
Integrating Sign-In with Ethereum into your Auth0 application is straightforward and takes only a few minutes.
Step 1: Install the Integration
Visit the Auth0 Marketplace SIWE page and click “Add Integration.” Select your target tenant, and the setup begins automatically.
Step 2: Generate Client Credentials
Use a simple curl command to register your app and retrieve a Client ID and Secret:
curl -X POST https://oidc.login.xyz/register \
-d '{"redirect_uris":["https://YOUR_AUTH0_DOMAIN/login/callback"]}'Replace YOUR_AUTH0_DOMAIN with your actual Auth0 domain.
Step 3: Create a Social Connection
Log into your Auth0 dashboard and navigate to Connections > Social. You’ll see “Sign-In with Ethereum” listed among available providers.
Step 4: Configure the Connection
Click on the SIWE connection and input the Client ID obtained earlier. If your app is a Confidential Application, also add the Client Secret for enhanced security.
Step 5: Enable for Your Application
Go to your application settings in Auth0, find the newly created SIWE connection, and toggle it ON.
That’s it! Your app now supports decentralized login via Ethereum wallets.
👉 See how easy it is to integrate blockchain-based authentication
Frequently Asked Questions (FAQ)
Q: Which wallets are supported by SIWE in Auth0?
A: The integration supports MetaMask, WalletConnect, Coinbase Wallet, Fortmatic (Magic), Torus, and any other wallet compatible with EIP-1193 standards.
Q: Is SIWE secure?
A: Yes. SIWE uses cryptographic signatures verified on the client and server side. Each login request includes a unique challenge tied to your domain, preventing replay attacks and phishing.
Q: Does SIWE require gas fees for login?
A: No. Signing a login message does not involve a blockchain transaction—so there are no gas costs for users.
Q: Can I combine SIWE with traditional login methods?
A: Absolutely. Auth0 allows you to enable multiple identity providers side by side, including social logins, email/password, and now SIWE.
Q: Is user data stored on the blockchain?
A: No. Only the signature is verified; personal data remains off-chain unless explicitly stored by your application.
Q: Is SIWE open source?
A: Yes. The specification (EIP-4361) is public, and Spruce maintains open-source libraries and an OpenID Connect-compliant Identity Provider server on GitHub.
The Future of Decentralized Identity
SIWE is more than just a login mechanism—it's a foundation for a new kind of digital identity. As part of the broader movement toward self-sovereign identity, it empowers users to own and control their online personas without dependence on centralized platforms.
Spruce continues to advance the ecosystem with open-source SDKs, libraries for direct integration, and ongoing improvements to their OIDC-compliant identity provider. The standard was built transparently in public forums with input from security experts and Web3 innovators—ensuring robustness and trust.
Meanwhile, the Auth0 Lab team remains committed to exploring Web3 identity use cases. From NFT-gated communities to verifiable credentials and DAO membership proofs, they’re building demos that showcase how Web2 applications can benefit from decentralized identity.
Developers are encouraged to follow Auth0 Lab on Twitter or join their Discord community to collaborate, share ideas, and stay updated on new experiments.
Final Thoughts
The launch of Sign-In with Ethereum on Auth0 represents a major milestone in the convergence of Web2 usability and Web3 security. By simplifying integration through the Auth0 Marketplace, developers can now tap into a global network of 300 million crypto users—with minimal friction and maximum trust.
Whether you're building a decentralized application or enhancing a traditional web platform, incorporating SIWE opens doors to innovative user experiences grounded in ownership, transparency, and user empowerment.